Turquoise Energy Ltd. News #45
Victoria BC
Copyright 2011 Craig Carmichael - November 5th 2011


http://www.TurquoiseEnergy.com = http://www.ElectricHubcap.com = http://www.ElectricWeel.com

Feature: Battery Technology Breakthrough!
'Grafpoxy' coated metal grills enable new salt electrolyte battery chemistries.

Month In Brief
(Summaries - and - gosh, editorial comment)
* Governments, Oil Companies, to ban electric cars?
* 7 Billion for Halloween & the coming Population Drop

Electric Hubcap System
* Motor contoller finally fixed, tested - works great.
* Motor over-revs at 42 volts and fails violently - analysis of failure, weak points.

Electric Weel Motor - no report

Mechanical Torque Converter Project
* Gear Reduction in Constantinesco's car - it doubtless had gear reduction at the rear axle to lighten the job of the mechanical torque converter.
* A better "centifugal clutch" mechanism
* Sprint is hard to move by hand at 4:1 (chain/sprockets) reduction - converter still has a big job

Sprint Car Conversion Project
* Drivetrain pieces come together day by day
* Fit into car and moved car by hand by turning torque converter drum
* Had main box rewelded, painted it all up with ersatz 'powder coating' (see TENews #42)

NiMH Battery Project
* Simple constant voltage charger for 12 V Battery Sticks: 15.0 volt power adapter + 2 diodes drop = 13.8 volts. Small resistor prevents overloading power adapter.
* Got 5A chargers for 3.99 $

LED Lighting Project
* LED Lighting: Good for your Eyes?
* BC Hydro subsidies for LED lighting?!?
* "Standard" LED Globe Light Fixtures For Sale (No wiring necessary. See: http://www.TurquoiseEnergy.com/TEcatalog/ => LED Lighting Products.)
* Also have a limited selection of 12 volt/car LED bulbs for local consumption.
* Simple 12VDC Lighting "Grid Tie" part -- 12VDC power adapter for AC side power supply.

Turquoise Battery Project
* Vanadium-Zinc cell
* Low conductivity: Aha, the culprits!
* Idea: epoxy-graphite coated copper grill current collector & terminal (turf graphite sheets and carbon rods!)
* Zinc electrodes in salt solution may be much better than in acid or alkali
* A working battery cell made! - no deterioration with cycling seen
* Grafpoxy grills work! Breakthrough unlocks the door to new salty battery chemistries!
* Carbon nanotubes with methylbenzene (toluene) solvent?
* Remaining issues for practical battery cell products



Newsletters Index/Highlights: http://www.TurquoiseEnergy.com/news/index.html

Construction Manuals and information:
Electric Hubcap Motor - Turquoise Motor Controller
- 36 Volt Electric Fan-Heater
- Nanocrystalline glass to enhance Solar Cell performance - Ersatz 'powder coating' home process for protecting/painting metal

Products Catalog:
 - Electric Hubcap Motor Kit
 - Sodium Sulfate battery longevity/renewal
 - NiMH Handy Battery Sticks
, Dry Cells
 - LED Lighting Products
Motor Building Workshops


...all at:  http://www.TurquoiseEnergy.com/
(orders: e-mail [email protected])



October in Brief

   I thought October would be much like September. For another week I plugged away day by day at the Sprint conversion, completing the drivetrain part by part and finally mounting the whole unit in the car to check the fit.
   And I figured out a better "centrifugal clutch" wedge system for the torque converter. Moving the car by turning the torque converter output drum pointed out what a big job the converter has to do if the Sprint is going to run well, even with the 4 to 1 chain drive reduction following it.

   The car work didn't stop me from doing the odd battery experiment... and I figured out where the high resistances inside my own batteries were coming from: the positive electrodes were swelling and losing conductivity - internally too, but even more they were becoming isolated from their graphite backing sheet and the carbon terminal post. Then I thought of a "grafpoxy coated grill" system for making electrodes. Turf the graphite sheet and the carbon rod - compact the electrode around a protected metal grill - the ideal construction! Grafpoxy coatings could do for rechargeable salt electrolyte batteries in 2011 what nickel coatings did for alkaline electrolyte batteries in 1899 - make them practical.
   I meant to leave it at that and get back to the Sprint and the torque converter, but I just couldn't leave such a promising development on the back burner! I made a test cell (NiMn-Zn). The negatrode was simply a sheet of zinc from a dry cell.
5 ohm resistance readings on the positrode from any point to the terminal looked promising indeed, and it did in fact work, apparently with gradual improvement and without deterioration over a number of cycles over a week.

Adding toluene to (hopefully) create carbon nanotubes seemed to up the current capacity a bit. Here was my first actual, usable battery. Open circuit voltage was around 1-3/4 volts, and it would drive over an amp (1 ohm @ >1 volt) for about 30 seconds and put out over 1.5 volts at 150 mA for 10 minutes, or 60mA for around 20 minutes, holding over a volt (>40mA) for another hour and more. A proper zinc electrode should greatly improve the running times, like maybe 20-30x.
   I also discovered there's a zinc peroxide (ZnO2) which might - possibly - make a good positrode. It's the first indication I've seen that such a thing might be possible. A ZnZn salt battery would certainly be very economical, and it should achieve over 100 WH/Kg energy density if the voltage is reasonable.







   I also made a few more LED lights, and I found out that BC Hydro is giving rebates to customers who buy approved LED lighting products. So I tried to get info in order that my LED light fixtures - which are much brighter than the 'LED lightbulbs' available in the stores - might become more affordable.
   The thought of possible sales - income! - brought LED lights to the forefront of effort. I bought more parts and focussed on defining "production models" such as a 6" globe (image), updated the Turquoise Energy Products Catalog to include them (and Handy Battery Sticks), and I attended a couple of small events trying to promote them. If ASHRAE engineers specify them for new commercial construction or renos, savings in HVAC equipment might actually pay for the LED light fixtures right in the capital cost.
   The day of the 17th and some time on the 18th was devoted to looking through LEDs at DealExtreme.com and putting together a big order - almost 400 $ worth. I hope I can sell a few LED light fixtures or lamps to recoup some of that, as money is already getting low and tax credits are at least six months away. In the process, I finished converting the Tercel to LED lights, except the headlights (haven't found any yet), and better determined which are the best ones to use. In the order are some more to do the Sprint.




   Later on the 18th I finally tested the motor controller. It worked great, but the motor over-revved at 42 volts and came apart violently. I neglected to consider that the higher top RPM from the higher voltage would be well above the design intent - maybe 3000 RPM instead of 2000, 9/4ths the centrifugal force. For a couple of days I had been mulling over the possibility of doing the electric outboard before my trailer insurance expired on the 26th. (I only used it once for the Electric Hubcap Outboard trials last November 6th. 50$ for one trip is very high priced insurance!) It didn't seem like a big job to get it running (tho these things tend to take much more effort and time than expected), but the busted motor broke the camel's back.
   Too bad - I might have actually sold a motor kit or two with an actual application for it that was demonstrated to work. Who knows for sure how long the Sprint conversion may drag on for with the untested torque converter plan and all the other things I'm doing? On the other hand, I now realize the rotor compartment needs a little more beefing up before the motors hit the market, and I'll be trying to improve the magnet gluing system a bit.
   AFAIK the controller was still working. On November 1st I finally ordered some IR2133 V2 motor controller boards, designed in mid August. On a list someone mentioned iteadstudio.com, and I ordered 10 boards there for half the price of two from APC - wow! High priced parts are what makes my stuff cost a lot, and this is a good find.

   One more motor detail that's been wanting is a better formulation of ilmenite for the coil coatings, one that won't flake off. I didn't have time to try out the zinc oxide additive. Until the coil coatings are improved the Weel motor isn't going to get done.

Governments, Oil Companies, to Ban Electric Cars?

   I've just heard a rumour that our (Canadian) government is planning to ban conversions of gas cars to electric. This sounds crazy, but it follows a secret provincial ban on registering converted cars last year in Ontario, evidently since repealed. Since it's virtually impossible to buy an electric car from a car maker, that would virtually mean a ban on electric cars. If true such a move, clearly at odds with the public interest and the whole planet's, can have only one real purpose: to prevent the public from making the switch from gasoline to electricity even with their own hands. This slow switch which has been happening on a small but growing scale with improving electric and electronic technology, and in the clear absence of any intent by car makers to produce practical electric cars -- besides a handful of overpriced units to bandy around and say "See, we're making them!" They sell one at inflated price where ten thousand are needed.
   Car companies can make a gas car to sell for around 10,000$. Canadian Electric Vehicles (just one example) can convert your gas car to electric for around 10,000$ Doing it yourself is cheaper. That's 20,000$ for a brand new electric car, partly made by hand with Canadian labour in small shops, and with a discarded gas engine system left over. From scratch, an electric car is obviously simpler and easier to build than a gas car. Maybe a basic one should cost 6000-8000$. Yet a Chevy Volt, essentially publicly funded by the billion dollar bailout to GM, costs over 40,000$ -- if they would actually sell you one. They claim they can't do it for less. Tesla motors, the one seeming bright spot since Zenn ceased production, is going public, but they're also ceasing production of their 100,000$ roadster. They plan to make a 50,000$ electric car next year, but there'll be a gap in production. As a privately owned and funded company it was hard to sabotage, but if patterns repeat, now that the miscreants are free to buy up the shares the new model will never be built, and Tesla will cease to supply electric cars, tho it's so well known now it may be kept "open" to prevent public outrage at its closure.
   Another disturbing rumour I heard this month (from what seems like a good source) is that the oil companies have bought up virtually all the battery making companies in China, and forced them all to sign agreements that their battery sales need to be approved by them. Obviously, a ban on sales of batteries for electric transport is the objective.
   Oil reserves, CO2 emissions and global warming would be dead issues were it not for the few actively, deliberately and cleverly blocking change. In fact, they might never have been issues. How can the 1% responsible for this or complicit in it look their neighbors in the face?

   And it would just one more little item in the gradual but ongoing curtailment of freedoms of we who were a much freer society within the memory of many. The gangsters that control the world's economy are now pressing us to the wall. Winston S. Churchill's "broad, sunlit uplands" for humanity that followed World War Two are being rapidly fenced off with "Private Property Keep Out" signs around them.
   The 99% are beginning to realize that the psychopathic greed and avarice of the 1% is destroying civilization, and are now demonstrating in numbers in cities all over. "They continue to block alternative forms of energy to keep us dependent on oil." is just one of a long, sickening list of indictments in the Occupy Wall Street Statement of Solidarity. If nominally democratic "bought" governments don't start doing the things people want and need done, when enough people have had enough, there may be a revolution. But what then? Military dictatorships might restore order, and maybe even summarily get rid of the gangsters who are lording it over us now. But it would likely be no freer. Is that what we want?
   It's easy to feel the situation is hopeless. But rumours from a confluence of individually suspect sources going back over 25 years say "Be not dismayed!" - that the troubled times we're entering are the beginnings of a grand correction, of gradually pulling this planet back into the main evolutionary sequence.
"Communism" showed its bankruptcy 20 years ago and has largely vanished. Now psychopathic "corporatism" is likely about do the same. Angels and other spirits await freewill human decisions, and when we try to do better, to learn, to educate, to contribute to real human health or planetary welfare, the results may be better and more far-reaching than we expect. All things work together for progress.

   Seemingly small electoral system changes would lay foundations for a proper democratic system. I suggested some of them in my 2003 booklet Fundamental Principles of Democratic Government . They should result in real leaders becoming electable, transfer the real decision making power from political partisan ("party") factions to the individuals in the legislatures where it belongs, and enfranchise citizens to instigate changes and actions instead of just to ineffectively protest someone else's imposed decisions and programs. The Choice Ranking vote, titled "BC-STV", was chosen as the best voting system by most of the BC Citizens' Committee on Electoral Reform in the same year, and Australia already uses it. In Canada (and Australia), it needs to be enacted along with direct popular election of the prime minister and provincial premiers. With the fair voting system where one puts who they really like best first regardless of preceptions of their electability, and without the schizophrenic election of two offices with one vote (MP and PM), the real ability of the public to elect numerous popular non-party figures who haven't worked their way up through a corrupt political hierarchy, would make the whole system much less open to corruption.
   Simply creating the Department of Progress (mentioned in various issues of TE News from #21 on) would provide an ability to foster both development and adoption of valuable technologies and new systems and institutions of governance, where they're needed, and rein in vested economic interests that attempt to entrench old and inferior technologies and systems with unfair tactics against the public interest. Such a department might itself carefully study and make recommendations for vital political structural reforms, for discussion and probable enactment by parliament.
   And as another example of things such a department might accomplish, surely it could come up with a well conceived national pension system, perhaps formed as a trust, that would unlock career changes for the many experienced citizens trapped a decade or more too long in one job by pension considerations, and set companies free to hire workers of any age.

   To attain to such improved systems we must recognize that we are one human family on one planet in a stupendous cosmos, spiritual sons and daughters of an infinite First Source and Center who encompasses all, and start to act accordingly. Perhaps John F. Kennedy had the essence when he said, "We all drink the same water; we all breathe the same air." We can't bring peace on Earth and goodwill among men unless our solutions are fair to everyone, everywhere.

   If those who are creating the problems turn and face themselves, as they must do on the next world if not on this one, they must recognize inwardly that they're one of a handful of rotten apples spoiling the whole barrel. They would do not only humanity but their own souls and psyches a great service by defecting from this evil - by opening their hearts to the people they're oppressing and helping to get long needed changes and advances implemented. They might well find themselves living in a better world, and discover a couple of things more precious than immense wealth and power - peace of mind and a true sense of self worth.

7 Billion for Halloween and the Coming Population Drop

   Officially our family hit 7,000,000,000 earthlings on October 31st 2011, "Halloween" in North America. Most of my life I've heard about the "population explosion", the "exponential growth" of Earth's population and how it just can't take much more. It had everybody scared like "global warming" does today. In fact, I think we were supposed to be over 12 billion by now and all starving.

   But birthrates in most of the world (with a few notable exceptions) now are such as to utterly falsify this picture. A couple of years ago I saw it predicted that the population would peak in 2055 and then start to decline. That was a big surprise to me. Now I'm even seeing 2035 instead. Halloween evening the 7 billion produced only two costumed kids to come to the door for candy, where 30 years ago, there were usually around 40. This doubtless indicates changing customs and I was late putting the porch light on, but there certainly are fewer children around.
   We now have an aging population, full of people like me who lived much of their younger life with the real possibility of nuclear holocaust, and who bought into "the population explosion" and thought it might be a service to humanity not to have kids. When we die off, there are few in the next younger age groups to replace us.
   I remember working for the Victoria school district in the late 1980s when numbers of portable classrooms were being placed on school grounds. Everyone was asking "Why don't you build additions and bigger schools instead of this makeshift fix?" But the far-seeing facilities manager said "Look at the birth statistics. In five years these portables will be being hauled away, and if the trend continues, whole schools will be closing." Thoroughly indoctrinated as I was to the "population explosion", that didn't make sense to me at the time - How could more and more people have less kids? But these things have happened. One high school that had 2200 students at its peak now has 800. Today, economic times are such that many in their 20s and even 30s are still living with their parents. By the time they are affluent enough to have a family - if they ever are - they'll be too old.

   While everyone was crying "Blizzard! blizzard!" the population explosion "snow" simply melted into the ground. It seems almost inevitable there will be substantially fewer people alive in a century than there are today, without any mass starvations, pandemic epidemics, or global catastrophe having intervened.

   But will they be affluent people free to live the lives they choose in a sustainable, boldly advancing civilization, or will 99% be regimented, poverty stricken serfs of 1%, living in a sick, polluted world and overburdened with 1,000,001 petty regulations against every deviation from arbitrary social, political and economic "norms" of the day to keep them in line?



A Battery Technology Breakthrough

Background

   There was something that wasn't explained in any battery reference book: why are standard dry cell positive terminals a carbon rod, when every other type of battery uses metal?
   It took me a couple of years of battery R & D to figure it out for myself the hard way: every metal I used within the positive electrode in a salty electrolyte battery oxidized away, including nickel, which protects the other metals in alkaline cells. The cells were soon left with a terminal post connected to nothing because the wire had disintegrated.
   The actual electrochemistry is of only secondary importance beside having cells that don't fall apart.

   Why was this nowhere explained? I suffered two years of failures because of this missing bit of info. Maybe it was so much assumed to be "common knowledge" by those writing the books that it didn't occur to them to mention it? Maybe the secret died with salty battery research in the 1880s? Whatever the reason, I explained it on Wikipedia in the "carbon-zinc battery" article so others might avoid this pitfall.

Evolution

   Once I understood it, I started using sheets of "expanded graphite", and carbon terminals salvaged from dry cells. Others have used graphite impregnated plastic sheets. But there were problems with this approach. Butting an electrode up against a carbonized sheet doesn't connect them together very well. My failures now took a different form: of initially poor conductivity within the battery, that - worse - deteriorated further over a few days.
   Browsing at (IIRC) GraphiteStore.com for ideas, I noted that they had "electrically conductive epoxies" with various metal powders in them, eg, silver, copper or nickel. That obviously wasn't going to solve the problem: if the metal particles connected with each other and to the outside, as they must to conduct, they would all corrode away just like solid metals did.
   But if one could do that with epoxy and seemingly with 'any old metal powder', what about with graphite powder, which wouldn't corrode? I tried it out (TE News #40) and got good results.
   Encouraged, I "glued" the offending parts together with the 'grafpoxy', as I called it, and made a battery. However, the initially fair conductivity gradually deteriorated, about like in previous cells.
   At this point, I pretty much set the battery research aside for a while and worked on other projects.

Invention

   In October I disassembled a couple of cells and measured the conductance of electrodes to the terminal posts. They were good when I'd made the cells, but now the resistances were very high - unusable. This was when I finally realized where the performance had gone.

   But having given the issue a rest for a while, a fresh thought crept in. Alkaline cell metals are coated with nickel to prevent corrosion. Why not go back to using metal parts, but coat them with impervious grafpoxy to protect them? Then salty batteries could be constructed much the same way as alkalines, but with grafpoxy coatings instead of nickel. The problem graphite sheets and carbon terminal posts could be discarded entirely.
   I made up several copper grills with copper wire terminal leeds or brass bolts soldered to them... why not solder and brass? After all, it's protected. Then I realized the 90º posts would be hard to work with. Doing them that way was perhaps a hangover from carbon rod thinking. I did some more - and re-did some of the first ones - with the leeds in the same plane as the mesh so they'd fit into the electrode compactor.

   Then of course, I made an electrode (NiMn) briquette around one grill. The resistance from anywhere to the terminal was only a few ohms, eg 5 - even better than I'd hoped. I put it in a battery case and used a piece of zinc from a dry cell for the other side.




First grafpoxied electrode cell, and my first really working battery.
   It worked! It was a real battery, and roughly equivalent to a standard dry cell in current performance per electrode area. Better yet, it continued to work through several charge and discharge cycles with actual (though minor) improvement with each cycle.



Further Development


   That was the initial success and, it would seem, proof of concept. But the mixture and application procedure needed improvement. A sheet of zinc was a crappy rechargeable electrode. An ill-fated second battery hardly lasted a day before the positrode structure crumbled and the leed wire came loose. Evidently there was a gap in the coating by the wire (tiny gaps were visible on some of the grills) - or compacting the electrode scraped some epoxy loose and left a gap.


Cell #2. I put it edge up fearing it might leak at the terminals.
I think I'll make them all this way up, and liquid filled.

   For best adhesion and coverage it may prove necessary to thoroughly clean the metal with several complementary treatments, similarly to if it was to be electroplated.
   If good results aren't forthcoming with that, I'll try two coats, hoping the second one will bring stiffer protection and fill any small gaps. If all other techniques should fail, I'll make molded grafpoxy grills with no metal in them at all except a terminal post cast inside a thick housing and - again only if necessary - pretty much outside the cell. But I'm pretty sure the epoxy is impervious and by good technique the grill can be made tough enough that extremes won't be necessary. The metal grill provides better current capacity, in a much thinner grill that leaves mainly active electrode substance for high energy density.

   For a third try, I used copper foil and riveted it to the grill, since the solder seemed to be a weak spot.












Copper grills with riveted terminals

I put up to four applications
of grafpoxy on to try and
eliminate tiny bare spots.















The structural parts for battery #3


A thick positrode, compacted around one of the grills.
The painted calcium hydroxide coating picked up some purple from the potassium permanganate.


Finished cell. The top was just set in place, not sealed.

   This cell also had some problems, but the positrode appeared to remain solid over a week or so. Then the cell was disassembled.

   The essence is there - it can be done. The door is opened to batteries of various new chemistries in salty electrolyte that were previously inaccessible owing to there being no really good and practical way to construct a salty electrolyte rechargeable battery. Some of these chemistries are exciting in that they hold promise for probably higher energy density than lithium ion and long or indefinite cycle life, and all for the price of cheap dry cells, or of lead-acid -- without its hazards and environmental problems.

   If and when economical electric cars and trucks have a day's highway driving range, gas vehicles will lose their monopoly. And when weeks of electricity from solar collectors or windplants can be saved up on-site in batteries, perhaps too the electric grid will no longer be such an indispensable part of modern living for everyone.



Electric Hubcap Motor System

Motor Controller

   After making the fuses bar clamp at the end of September, I wasn't happy with it and made another the next day, that supports the bar with a couple of plexiglass pieces when the fuses are being inserted, and holds the copper bars apart (thin strip glued on beside bar after photo) so the fuses can't accidentally be bypassed. Still lots of room for improvement - next unit!


Fuses Bar: Clamp (arrow, right); Support (arrows, left)

   It wasn't 'till the 18th I finally got around to testing the controller to make sure it actually worked. I started at 12 volts and gradually added batteries until I got to 42 volts. At that voltage the heavy rotor would go from 0 to max RPM in under a second, maybe even 1/2 a second. In fact, accelerating with over 80 amps (...pretty impressive current for a single string of D cells!) it went well over max and suddenly the motor broke apart violently, the rotor side ignoring the C-clamp that held it and ending up on the floor.


Busted Motor. One magnet punched a hole through the particle board table it was clamped to.

   I hadn't considered that going from 36 volts to 42 would up the maximum RPM the motor would attain, and I wasn't measuring it. The motors had already been going up to 2200-2400 RPM instead of the intended 2000, and 42 volts might take it as high as 2600-3000 RPM, with double the centrifugal force I had intended it to withstand.

   I'm thankful I wasn't in the line of fire. Thinking of the guy doing the flywheels to store energy in the late 1960's, whose ideas for powering even buses from flywheels were featured in several Popular Science and Popular Mechanics magazines until he was killed by a big flywheel that flew apart spinning 50000 RPM in his lab, of jet engine failures, and of my own previous magnet glue failures, I've gotten into the habit wherever feasible of mounting motors vertically and being face on to it rather than edge on. (The researcher's death was the end of the idea of using flywheels to store energy until very recently - over 40 years later.) One magnet made a 1" x 2" rectangular hole (and the exit was much larger) right through the table the motor was clamped to. (It was a cheap particle board end table... but still!...) I collected the five loose magnets from around the room. Three of them were badly chipped on one end, but I didn't see any holes or gouges in the walls or ceiling. They're probably what bent all the bolts inside, ripping them out of the PP-epoxy center plate.

Analysis of the failure

   The first thing that was virtually a given was that a magnet must have come loose from the rotor. This would have become an obstruction in the rotor compartment, hitting other spinning magnets. It appeared that the five magnets that came off had separated from the epoxy, rather than the epoxy from the powder coating paint, or the paint from the undercoat or from the metal.
   They also separated from their polypropylene strapping, or (with two of them) the strapping separated from its epoxy on the rotor and stayed with the magnet. The strapping was mostly but not entirely intact, unripped. Examination of the rotor disclosed areas where not much strapping area was well embedded in the epoxy, especially near the inner ends -- with one such weak spot on each side of the same magnet. This could cause the magnet under stress to pull strongly away from the rotor on the inside. Once it broke free of the rotor behind, it would have swung out, ripping the rest of the strapping from the epoxy, and become a projectile.
   Better workmanship might have prevented the failure... or just delayed it until reaching a bit higher RPM. Improving the strapping configuration might be helpful if I can think of a simple way to do it. It's easier in theory than when you've got a bunch of gooey epoxied strapping that doesn't want to stay put. If I'd tried inserting a screwdriver under the strapping at various points, it might have disclosed the weak spots. But screwdrivers and supermagnets don't mix very well either. Maybe something plastic.

   The rotor compartment's outer cover, made of four winds of PP strapping, was ripped in one place. It looked like a magnet probably flew out from there. The point was near the top of the motor, so it wasn't the magnet that made the hole in the table underneath. It may have been the two magnets I found across the room stuck together. The strength of the PP strapping is impressive, but not unlimited. A thicker outer wall appears to be required. But then the outer wall will be so close to the rotor it may hinder ventilation. I also note that the outer strapping wind was delaminated from the others. Making the outer shell by casting it should also be stronger.

   The bolts holding the rotor compartment to the stator side of the motor were all bent, having been hit by the loose magnets. (This is probably where the magnets got chipped.) These bolts pass through the rotor compartment just inside the outer cover. If the cover shell were thickened so that the bolts passed through holes within it, the damage to the bolts would probably have been avoided and the case might not have failed. To enclose the bolts is a second reason to thicken the outer wall, and to cast it. But there's not much room between the bolts and the rotor since I minimized the diameter of the motor. I'd really rather not redo all the molds and everything unless there was no other way!

   The center ring/plate between the rotor and stator compartments protected the coils and stator side from damage, except pieces of the ring itself ripped/broke apart at the bolt holes, allowing the motor to come apart. This was the first ring made with the new mold casting technique, and I knew it had some dry spots without epoxy. These weakened it.
   Furthermore, I hadn't expected any real trouble, and only six of the nine bolts were installed. All nine might just have made the difference. But it may be that the magnets ripped the bolts out one by one, and there would simply have been nine rips instead of six.

Corrective Actions:

1. Make a careful inspection of every rotor after magnet & strapping installation. Try to insert something flat under the epoxied strapping and otherwise hunt for weak points. And maybe paint on an extra layer of epoxy after it's otherwise finished.
2. Try to figure out a better configuration for the strapping that's inherently stronger. I think casting it should stiffen it.
3. Recess the magnets in a bit from the edge of the rotor - maybe .1".
4. It might pay to rough up the bottoms of the magnets a bit with sandpaper or scotchbrite before applying the epoxy. On the underside, the magnets separated smoothly from the epoxy.
5. Thicken the outside wall of the rotor compartment, and drill holes through it for the bolts. Or maybe just the area in line with the magnets? (better for ventilation?) On second thought, I think I'll mold the outer wall.
6. Always install all nine bolts to hold the rotor compartment together and to the stator compartment.
7. Snip the tines short on the T nuts so they don't cut into the plastic center plate so much. Or bend them over. (In some places, the center plate ripped at the tines.)
8. Use the new shaped center plates with thicker outside edges to hold the nuts/bolts. Ensure no dry areas after molding.
9. Make a motor controller with a microcontroller that monitors (among other things) motor RPM and reduces power if it hits max.
10. Going back to 36 volts instead of 42 would pretty much eliminate the potential of serious over-revving. That would make battery charging details easier too -- three 12 volt chargers, three 12 volt solar collectors on the car roof (800$ option), and no single 6 volt units that have to match the 12s in current.



Mechanical Torque Converter Project

   Someone gave me a washing machine clutch mechanism to examine. With my last designs, the motor would have to get up enough torque to overcome the springs holding the wedges in the slots before it could start moving. I was only hoping that the maximum pressure for starting the motor was also at least sufficient pressure to develop good force to the output. But this is backwards. Ideally the stopped motor should be free, unloaded, and force developed should be proportional to motor speed.
   I've decided to modify the design, and use centrifugal force to push the wedges into the slots. This implies that the wedge arms must be given a certain amount of mass to push them out with some 'optimum' amount of force as the motor spins. Instead of having the springs push the wedges into the slots, they'll hold them away from the slots, retracted, until the motor gets up some speed, somewhere in the upper 100's of RPM.
   Thus the unit will act as a centrifugal clutch that will cut in when the motor is going fast enough to develop some force - the sort of force that might start to move a car on level pavement. The mass of the arms and the strength of the springs can be varied to see what works best. It'll be unlike a centrifugal clutch in that it will neither solidly 'engage' nor 'slip', but the greased wedge will freely slide across the flat areas, bumping against the edge of each slot as it comes to it.
   The force of each hit will largely be proportional to the square of the motor speed. The frequency of the hits will depend on the relative speed between the motor and the output rotor, which depends on the amount of torque required. The torque will I think be the motor torque times the total distance between slots, over the distance for which the drum is driven at each slot - around 18 to 1.
   Since I haven't made the wedges/arms/springs part of the mechanism yet, design changes - so far - don't require any reworking of things already done.

   Looking at the washing machine clutch, I note that the arms could be on the outside of the output drum. In this case they would pivot in the middle, with the weight on one side and the wedge, facing inwards, on the other. However, I'm not sure if this would have any particular advantage, and there isn't room to fit it without redoing important parts of the frame, since I hadn't planned on anything larger.
   Seems to me that if the diameter is to go up, it should probably be the output drum that's made larger and the arms and wedges should be kept inside it. It also occurs to me that the drum and slots could be made wider - if not an inch, then two or three or four inches - to distribute the force of the hits and so prevent damage from relatively powerful forces.

Constantinesco's car & converter: gear advantage

   Although Constantinesco eliminated the entire transmission of his cars with the torque converter (which was built into a two cylinder engine in his production model), there was a gear at the back axle for forward-neutral-reverse. It belatedly occurs to me that this gear probably was also a reducing gear. Given the higher RPMs of a two cylinder gas engine and the fact that 40 MPH was probably a good top speed in the 1920s, it wouldn't surprise me if it was as much as around 10 to 1 reduction. This means that his torque converter had a much easier job to do than I what was thinking. That might explain why his oscillating  masses converter was successful but no one since has managed to duplicate his success.
   Doubtless the chain drive I've put in the Sprint, or a planetary gear reduction following the torque converter before a vehicle wheel, reduces the converter's job.

Test Setup?

   I thought of making a test setup using the sprint car drivetrain C-clamped to the workbench. Instead of hooking the input rotor to the motor, I could hook it to a hand crank. I could mount a fish scale at a 6" radius from the output drum and measure the output torque. I'd have to estimate input RPM and torque. I had another cut down trailer axle for bearings for the same 1" shaft as the motor, so the input rotor could be moved from the crank to the motor without modifications (except maybe stronger springs so it'll engage at a higher RPM).
   A few days later it occurred to me that all I had to do was put a longer axle on a motor, so that it stuck out the back end. The handle could then go right on the motor shaft and nothing extra except the handle need be constructed.

   I hope in this way to get more of a feel for how it's working and what gives it more or less effect and how much effect. On the other hand, I can't duplicate motor RPMs by hand.
   What's needed now is time to get to the job!



Sprint Car Conversion Project

Fittings

   On the 2nd, I fitted a plastic plate on the hole in the floor where the gearshift lever was, a plastic plate on the console, the console back into position (with a couple of new brackets to mount it), and the key "Park" release cable and the forward-neutral-reverse switch into the plate. Around the switch I put an aluminum shroud to make it simple to shift to where you mean to shift and prevent accidental shifting. I've had this shroud safety idea in mind for well over two years, and now it's finally taken form, albeit with some rough edges. I'm leaving the cable in as another safety feature: to switch into or outof "Park" (which now only allows the key to be removed and locks the steering), you have to pull the cable. Takes two hands. I'll probably fancy it up with a lever to pull the cable at some point.
   A means for having to press on the brake to go from neutral into "Drive" (forward or reverse) would be tricky, but I don't think it's necessary since the car won't start to move until you press on the electron pedal.
   Of course, the parking brake becomes vital, since there's no other way to lock the wheels.

   On the 3rd, I fitted the speedometer gear to mesh with its gear on the differential, using a short bit of angle iron as a mount. I don't want to do an electric car and not know how fast it's going or how far it's gone! I wonder if it should have an oil drip too, seeing the gear teeth and the bushing are no longer running in an oil bath. It does turn slowly - perhaps grease would do.

   On the 4th I fit an axle mounting for the small sprocket and the torque converter drum -- a cut-down trailer wheel bearing hub from an early motor. This required making another large hole in the mounting plate, which I tackled with the same technique as the differential bearing holes. On seeing how it all fit, I saw I'd have to cut new slots for adjusting that side, do a new axle to fit... and move the speedometer gear.

   The next day I found a slightly better bearing hub and fit it, and cleaned up some details, including cutting an axle rod, extending the slots and moving the speedometer gear. All this stuff takes a lot of time when things aren't ready made for you. It's one thing after another, one little job at a time (inevitably taking much longer than anticipated), all adding up.
   On the 6th I got chain and fitted it in. It turned out that the bulk chain was the long-lasting sealed chain. Cranking the unit around by hand showed that all those little rubber seals on the links really do give it a lot of resistance to turning. I suspect it'll reduce efficiency enough to show up clearly in reduced performance and mileage. I'll definitely try out some other chain as well once things are working, to compare and see if that's the case.
   I took the unit in to see how long the chain needed to be, and the merchant at Victoria Motorcycles offered to redo my amateur welding free. His good TIG welder could do a much better job, just to help out. True, I would hate to have the welding fail on the road, but I didn't think it would, and this being the main unit that everything else fitted onto, I couldn't give it to him without stopping work myself.

   In the next couple of days I made some brackets and bits and fit the unit onto the original engine and transmission mounts, and I cut a keyway into the shaft. I'd been told I could do this properly with an end mill using the drill in my CNC machine. But someone else said the mills should only be used in a collet chuck, not a drill chuck, and anyway Western Equipment was out of 1/4" end mills. Instead I bought a '1/4" lathe tool', which was the square shaft key I wanted... but made of tool steel with sharp beveled edges on the ends. I roughed out the keyway slot with the angle grinder, then used a hammer and the 'lathe tool' to finish gouging out the inside corners of the slot. This, plus the close fit in the sprocket gear and in the torque converter drum hub, gave the desirable close machined fit, albeit with some rounded outer corners on the shaft. On the 9th, I tried out the assembly in the car. It was a bit too far to port - the inner CV boot end fitting slipped off its place on the starbord CV shaft when I put it in. Later I moved one bolt hole that positioned the rear end 1/2" over and the shafts seemed to fit okay.
   I tried moving the car by turning the torque converter output drum. It was easy enough on level lawn, but slight hills were much harder, and I couldn't get it to go forward (uphill) from its little depression at all. The torque converter is definitely going to have to perform in order to drive the car readily across the lawn! 4x motor torque out (for a total reduction of 16x) may be minimal.
   There was nothing to attach the torque wrench to so I couldn't get actual figures of the forces needed. It would be nice to rig something up.






    On the 16th and 17th, after having done little on the car conversion for over a week, I galvanized and painted the drivetrain unit using the "ersatz powder coating" technique I developed (TE News #41). Looking at the main piece before zinc spraying it, I finally decided I should take Jim up on his offer to re-weld it before I did it. Jim was only marginally happy with his welding, but it looked great to me. It was 1000% better than mine. I had interesting conversation with Jim and his next door neighbor, who had been involved with the original development of gas concentrating solar collector tubes for hot water. He was doing lovely rockwork landscaping in his large back yard. Jim was also very creative with machinery, and together they had made a big wire tumbler for sifting soil. The soil came out underneath, and it dumped the rocks and roots out the far end.
   The next day I tested the repaired motor controller (it worked great) and promptly damaged the motor by over-revving it. The car won't go anywhere until the motor is repaired or a new one made.
   Not wanting to tackle it the next day, I just did a bit of wiring in the car. I wired the forward-neutral-reverse switch, ran the cable from the console out to under the hood for the controller, and one from the "electron pedal" to the console. I used rubber 3-pin trailer light plugs for the pedal and the switch, since they're reliable and automotive. I decided none of the controls would be soldered onto the main cable to the motor controller - it would all be plug-in.

4runner Truck Conversion Thought

    It occurs to me that keeping the original differential was the right thing to do on the Sprint, and it will probably also be the right way to do the truck with the big Weel motor. That'll make the truck a front wheel drive with both wheels driven, and all that heavy 4 wheel drive transmission stuff can be eliminated except of course the rear axle.
   (The Weel motor should have 9x the torque of the Hubcap motor, but it won't fit under the Sprint's hood.)



Nickel - Metal hydride Battery Project

12 volt, 10 amp-hour, D cell Handy Battery Sticks (~26" long, 1900g): $105
12 volt, 10 amp-hour, D cell Quintos Battery Sticks (~7" long, 2200g): $120
6 volt, 10 amp-hour, D cell Battery Sticks (~14" long, 1045g): $55

12 volt, 2/6 amp NiMH charger (adjusted for NiMH): $60

What's with Prices?

   Canadian Tire had a NiMH cordless drill on sale for 35$. It was 18 volts, 3 amp-hours, which is 54 watt-hours. It works out to only about 25% more than I'm paying per watt-hour for D cells. I guess they're throwing the drill in for free! Furthermore, I found a retail price on line for that drill's battery alone: 78.46 $. Go figure!

Simple NiMH Constant Voltage Battery Chargers!

   I've written (plenty) about how 1.38 volts per cell or 13.8 volts for a 12 volt battery is an ideal constant voltage to charge NiMH batteries at. It's not the fastest way to finish the charging to 100%, but if there's no big hurry it doubtless puts the least stress on the cells, maximizing their cycle life. It seems ideal for the car, scooters, solar, and any batteries that are normally left on charge for long periods. But the thought of producing such a charger for sale with the batteries seemed rather daunting.
   In Quealle Electronics on the 11th, Fred pointed out as I considered LED power sources that the newer switching power adapters are an exact voltage (±5%), unlike the older very approximate ones (a fact that had only gradually been working its way into my brain while doing LED lighting), and that quite high current models were available (and in stock!) at 12.0 and 15.0 volts.
   Lets see now... a 5 amp adapter at 15 volts, with a 1.2 volt drop from two diodes or a darlington transistor, is a 5 amp, 13.8 constant volts charger! There's my 'ideal' NiMH charger, and doubtless cheaper than most any lead-acid charger!
   And the 12 volt models... there was an off the shelf component for the line side of the "LED lighting grid tie"! (Per my plan in TE News #43)

   After thinking about it, I went to Quealles and bought a 15 volt adapter, 1.3 amps. To charge the car I'd want three 15 volters (and one 7.5 if using 42 volts) in as high a current rating as was available... I thought they'd still be much cheaper than chargers intended for lead-acid, but the price did go up with amps.
   I used a diode bridge for the two diodes. It seemed to drop about 1.5 volts instead of 1.2, but the power adapter was about .2 volts high anyway. I tried to charge a 12 battery stick that was quite low - down to 11 volts. (I drained it for several hours on an LED light.) The battery wanted more current than 1.3 amps, and the power adapter pulsed on and off, not doing a lot of charging. I put a one ohm resistor in series to limit the current. That did the trick! The battery charged up overnight. It seems like a good arrangement. As the battery voltage rises, the current drops and the resistor drops less and less voltage until it is trivial. It does slow charging somewhat, especially when currents are high... but then that's what it's for.
   Higher current supplies would handle lower value resistors, perhaps 1/4 ohm for a 5 amp adapter. All assuming the batteries aren't even flatter than the one I tried - to handle really dead ones they might possibly need higher values. But I'll go with this for now. The one I've got will charge the odd battery stick if the sun isn't shining on the solar collector (which does over 3 amps). It seems I've found a simple way to constant-voltage charge my electric car batteries and any scooter/e-bike batteries I sell.

   Later someone sent me a foto of some 12 volt, 5 amp power adapters at XS Cargo for 3.99$! (Taken with his phone/GPS/...) I went down and bought ten. It turned out they had a cigarette lighter socket for an output. No matter - that can be changed! (Maybe APP 30 amp connectors from Queale Electronics.) They open, and I have little doubt I'll find a 12 volt reference part inside that I can change to 13.8. Then three could charge the three banks of 12v batteries for the electric Sprint - or even two or three trios in parallel. That's sure a cheap setup to charge 36 volt batteries at 5, 10 or 15 amps!



LED Lighting Project


"Standard" 6 inch globe fixture

LED Lighting Fixtures are now For Sale - from $80 ($62 without wall power adapter)

   I've put several LED ceiling/wall light fixtures in the Turquoise Energy Products Catalog, with options for brightness and form from parts I have or have on order. At up to 1800 lumens they're about the brightest LED lighting around, and the 90 lumens per watt ones must be the most efficient lighting available, far surpassing minimum "Energy Star" requirements. (I also have a limited selection of automotive LED lights for local consumption.)

www.TurquoiseEnergy.com/TEcatalog/  =>  6. LED Lighting Products

   It seems the cooler the LED runs, the brighter it is, and the longer it will take to dull. As well as using lower currents and external power adapters (with their heat outside the fixture), I'm maximizing the efficacy of the heatsinks in these fixtures, using the roofing flashing fanned fins construction I developed for the motor controllers. It seems the ambient air temperature also plays a big part, so good ventilation is also a feature. In what I've measured so far, air temperature has been below 50ºc and the heatsinks at the LED below 70ºc. Under those conditions, projected life before dulling to 70% of the original brightness is around 100000 hours - over 11 years of running time; 80 years if run 3 hours a day.
(source: Cree LED manufacturer graphs)
   The external power adapter plugs into the original light socket via a screw-in receptacle.

Reasons to use LED lighting

1. White LED lighting isn't sunlight, but it's the whitest artificial light available with a broader, more even spectrum than any other type. With similar light levels, you'll help your eyes, and potentially save your kids from needing glasses.

2. Save money. LED lighting is costly up front, but it pays for itself in electricity savings within a few years - at best within a year. The electricity saved helps the environment.

Reasons to use Turquoise Energy LED lighting

1. It's the brightest LED lighting around. Most of what's available isn't really bright enough to replace common lightbulbs.

2. It's diffused into a white, even glow. Too many LED lights have intense pinpoints of light that leave spots in front of the eyes. This may in fact be a long term visual health hazard, and some LED emitters are bright enough in the blue spectrum to cause retinal damage if viewed directly from close range.

3. It's the most efficient - more light for less watts gives the biggest electricity savings. At 10¢/KWH, a 100 watt, 1600 lumen bulb uses 88$ of electricity if left on for one year. The 15 watt, 1400 lumen LEDF5 fixture or lamp uses 12$. And it looks brighter - visually, the 11 watt (9$/yr), 1050 lumen LEDF3 is a closer match for the 100 watt bulb than the LEDF5. A 26 watt compact fluorescent (which seems dimmer than either) is 22$/yr, and other typical LED lights are perhaps around 15-20$.

4. It doesn't flicker. Many bulbs don't have room internally for a proper filter capacitor and go on and off at 60 Hz. TE fixtures use regulated switching plug-in power adapters or internal filter capacitors to smooth out the DC power.


600 lumen, 9.5 watt Lights of America bulb (left) versus
Turquoise Energy 1050 lumen, 11 watt LEDL3 lamp with plastic jar diffuser,
with identical lamp shades on both.


800 Lumen, 12.5 watt Phillips bulb (left) versus the LEDL3 lamp.
The LEDL3 is brighter on the left because its light is somewhat aimed,
and it's pointing to the left, away from the wall (and in this case, mirror).

   A friend had bought two of the best screw-in 120V LED bulbs presently available. I took the 3-emitter LED lamp and (in his only dark room, the bathroom) we compared it with his bulbs, with the same lampshades.
It seems these commercial bulbs don't flicker like some do. (The other bulbs seem brighter compared to mine in the fotos than they did in life... or was I just prejudiced?) I prefer the "cool white" to the orangey "warm white". I think we're just so used to orangey incandescent lights - and perhaps instinctively know we're bothered by whiter fluorescent lights - that a "friendly" whiter light seems strange at first.

How much electricity is going to be saved?

   According to an LED lighting web site, 3.7 terrawatt hours of electricity (presumably worldwide) was saved in 2010 by LED lighting. That's getting up towards the whole output of BC's planned Site C Dam. And LED lighting hadn't replaced very much other lighting yet - it's just the beginning.

BC Hydro Rebates on LED Lights! - Nope. - Maybe.

   One day I remarked to a friend that if BC wanted to get serious about saving electricity, it would encourage LED lighting manufacture with the "Innovative" Clean Energy fund, or have BC Hydro subsidize LED lighting products or production. The very next day he showed me a flier he was looking at, in which very substantial BC Hydro rebates were available on LED light bulbs.

   I thought "Hmm, I'm making much better LED lighting products than those, but they're expensive. Surely they would qualify for the program." So, after some difficulties trying to navigate the BC Hydro web site or contact anyone who knew anything, I wrote (twice) to ask if there was an application form.
   The information was utterly discouraging. I found that having better, more efficient products than anyone else evidently wasn't good enough. They wanted references from five previous corporate customers, I had to offer a full range of lighting, not just LED, and a 2,000,000 $ liability insurance policy with BC Hydro as a beneficiary would be required. If I could miraculously meet or get around the first two requirements, It seemed likely to me that if any insurance company would even touch something like this, it would be at a premium I'd never recover in sales. I put BC Hydro approval out of consideration.

   Then I got another e-mail from another person, answering my previously unanswered first e-mail of the previous week that I'd given up on, saying if the lights got "Energy Star" approval, they'd be listed on the BC Hydro website. The first person to reply hadn't mentioned that vital detail. After some confusion about the requirements I found out that "Energy Star" wasn't part of BC Hydro and they sent me a link to it.
   They should easily surpass Energy Star requirements and I'll be making submissions. Thus prospects seem good of at least getting them listed at BC Hydro. Whether or not that means the customer can get the rebates I'm not sure at this point... Probably. It would sure help!

"Standard" Ceiling Fixture

   I decided I'd better make exactly what I wanted to sell and have it on hand. Lamps are great, but I also wanted installed light fixtures. I thought I'd put together a couple of 6" globe ceiling lights before breakfast on
Thanksgiving day - and not install at least one, to have as a portable sample. By 4 o'clock I had one done, after various small problems, breakfast, lunch, etc, and the other was ready to wire.
   What goes inside the light is somewhat flexible. This light was 7 watts (~.8 amps at 9.0 volts), but the AC amp probe said .11 amps going in at 120 volts, which is 13 watts. Not very efficient for a switching type power adapter - and it does indeed run warm. The emitters themselves weren't much better - the lamp runs much warmer than those with the Cree emitters. I drilled some extra ventilation holes. These were the same LEDs as I used in the first light in the upstairs hall (ceiling now filled and painted), and I've never opened that globe up to check the temperature. It stands to reason, however, that if one LED converts 75% of the energy to photons, and another converts only 50%, the second one will generate twice as much heat as the first. I got seven of these warmer-running emitters, but I probably won't get any more.

   I'm almost out of emitters, but the friend with the bulbs spotted a 12 volt emitter that seems a good deal amongst the high brightness ones at DealExtreme.com , and I ordered some. Three of them should make a good 1600+ lumen light. Lumens per watt is an important measure of efficiency -- lumens per dollar is an important measure of economy.

   I made a couple of drill templates (so far: for 6" globes and 7" low profile mushrooms) for the heatsinks. Those'll do for occasional orders. If I actually get quantity orders I should set the CNC machine to drill the holes. Hopefully I should be able to get the rebates, and the time and the parts cost down, so it all becomes worthwhile to make them and sufficiently economical for customers.
   I also have a plan for a CNC machine addition to hold and rotate the plastic fixture caps so their holes can be automatically drilled. Evenly spaced vent holes would look better even for single unit orders.

LED Car Lights

   I finally got around to doing the lights on the front half of the Tercel - the car is now LEDs except the headlights. You'd think a 5" x 7" standard halogen headlight would be about the easiest thing to find of all, but I haven't seen one yet (except for a horrendous price), and I have yet to see a plastic 5" x 7" one I could cut the center out of. And I sold the 450 lumen, 12 volt bulbs I was going to try with that idea, to someone living off-grid with 12 volt power. I've ordered more. The Sprint should be easier as the bulbs are separate from the fixture.

   The one hitch in the proceedings was the front turn signal lights. The LED 'bulbs' had a PC board projecting outwards, right above the socket, and the sockets had a restriction there. They wouldn't quite go in. So I tried the ones I'd put in the rear, and they fit. I put the ones from the rear in the front, and the new ones in the rear, where they did fit without trouble. Now I know which type to reorder of two quite similar bulbs.
   I also found which model of small bulb spreads the light which way. One is better one place, the other seems better in the other. Both are quite passable, and cheap.

What's White in Light?

   Looking at a spectrum of a "cool white" LED emitter, I had the thought to check it against other spectra rather than just to assume the the ideal was a straight horizontal line. Ordinary sunlight is perhaps the ideal -
kids who get out in the sun an extra hour a day or more are less likely to end up wearing glasses (and are less prone to getting cancer because they're getting more vitamin D). But sunlight isn't entirely a straight line spectrum even in the visible range.




   All the lights look different than sunlight. The violet and blue end of the spectrum is missing in the incandescent. Evidently all fluorescents have a nasty big blue spike right at 440 nM (mercury vapour) and some other spikes. (Cool white fluorescent has been banned in some jurisdictions, especially in school classrooms.) Then the main range tends towards reddishness.
   LED lighting is of course quite new. It doesn't have fluorescent's spikes. Ultra-violet and violet are missing, then the blue of the actual emitter is prominent. But then it's weaker in the cyan from around 475 to over 500 nM. Above that, the phosphor gives a broad band, then the far red end is very weak.
   But I tried looking at some reddish objects under an incandescent and an LED light. One in particular, a tab of the colour from a magenta toner cartridge box, looked rather brownish under LED and brighter red under the tungsten. Aha? However, the next day I found it looked brownish in daylight - even here the LED was the truer colour.

   I ordered a few coloured emitters (red, green, blue) to experiment with, to try and fill in weaker bands and see how I like the light. However, those seem to be colors already well covered by the white. An indigo (far red) emitter (eg, 675 to 725 nM) might make it extra pleasing, and perhaps with a cyan at 500 nM the spectrum would be very even through the visible range except in the far violet. I see a cyan emitter listed at Cree in the XLamp7090XR series, but not indigo. I also didn't see the cyan at DealExtreme.com, so I'd have to track them down.



Some coloured and white LED emitter spectra

   But I must say that it appears any improvements would be minor. White LEDs through a white diffuser are the most even, whitest artificial light available. An incandescent light now seems a touch drab and orangey to me beside a good LED one, even if it does activate my solar powered calculator from about the same distance.



Turquoise Battery Project

   I gave up on the first permanganate/nickel - zinc cell. The case was all cracked up, and it wasn't performing or improving. I decided to re-use a previous case, which was in good condition, and dug out the electrodes. On something of a whim, I decided to try out the vanadium electrode from that case (which I extracted mostly intact) with the zinc.

The culprits in poor conductivity

   Trying to measure the resistance of the used vanadium electrode, if it didn't read as being open or negative resistance, it was many kilohms. When I made it it measured around 50 ohms. Here may be a good clue as to the poor conductivities: perhaps either with wetting or with charging, or both, the positrode (or both electrodes) swells and the conductivity drops drasticly. Perhaps I need to put more graphite powder in these electrodes to account for this, perhaps compaction is insufficient, or perhaps there needs to be nowhere in the cell for it to expand to once wetted. With dry cells there's nowhere for the compacted powder to expand to, whereas I just have some sponge rubber pushing the electrodes together. One or both can "fluff up" if they want to, inevitably losing their good conductivity. This would indicate that I should modify my construction.

   Measurement of the nickel/permanganate electrode disclosed that it was megohms from the surface of the electrode to the terminal post. That must be the reason for the poor cell performance. Measurements from one spot on the electrode to another varied wildly (as usual), from ones of kilohms to megohms. The nickel negative, however, still had very low resistance, tens of ohms. (As it was removed from the cell, measurement to the separated post wasn't useful.)
   Evidently the positrode is the problem, but in this case much worse owing to poor connection to the post rather than just swelling. This was the electrode where I'd coated the surface of the plexiglass with grafpoxy, then pressed the post in from the outside and the graphite sheet onto it on the inside, expecting great conductivity, which it had when made. If I pressed on the electrode where the post was, resistance would drop to about 1K ohm. Evidently something has delaminated - so this aspect of the construction also needs to be modified.
   Later I did more checks on the vanadium. I pounded it with a hammer to try to "un-fluff" it. It didn't seem very fluffy. I found that the new meter was giving pretty weird results, and the conductivity within the electrode probably wasn't as high as it seemed. Then I found that like the other one, the resistance to the terminal post was high, tho not as bad.

V-Zn cell (~~2.3 volts)

   Notwithstanding the high readings on the vanadium, the cell performed far better than the previous one, and on a par with previous best results. 25x better? Another 50x again and it would be a real battery.
    Open circuit V-Zn cell voltage was around 2.3 volts. It's hard to be exact as it still had high self discharge and dropped from 2.4 to 2.25 over a few minutes while I watched. Less Sunlight dishsoap in the positive next time, and none in the negative!

Grafpoxy 'plating' of metal electrode structures

    Another idea struck me as to electrode construction: if a copper or other metal grille were simply coated with graphite-epoxy, would it not be immune to the electrolyte? The part of the terminal inside the case would also be coated, and of course the opening sealed. This might provide a better electrode collector and terminal post, of simpler construction. It could be to a salt electrolyte cell what nickel plating is to alkaline cells. This construction would count on the 'grafpoxy' being completely impervious to the electrolyte, and on obtaining 100% coverage that didn't get scratched or abraded away at any point. Epoxy is very sticky and tough, so for the moment, I'll assume these conditions can be met and try it out. I've become convinced this is the way to do it if it works.

Some Conclusions

   By October 3rd, I figured I had a pretty good idea of where the main problems lay. After running a discharge test that day for seven hours, I remembered how running off to record the latest battery every little while reading disrupted the process of working on anything else. (An automated data logging system would be most helpful!) So I decided to drop the battery experiments for a while and work on other things.
   I need some way of making cells that can hold the positive electrodes compacted as well as hold pressure and not leak. Doubtless better initial compaction is required. Probably metal structures coated with grafpoxy can serve as electrode elements, which will simplify things and - I trust - provide good conductivity.
   I might end up with something like cylindrical cells with wrapped up electrodes after all, as is done for NiCd and NiMH dry cells. I'll pause and consider all this, and perhaps some inspiration(s) will strike as to improved ways of achieving the several goals. Or I can see making cylinder cells with coated grills and the ingredients simply forced [pounded?] in like cheap dry cells. A 5" long piece of the PVC irrigation pipe I've been using for NiMH battery sticks might make (without detailed calculations) a 30 to 60 amp-hour cell.
   When I have cells that actually work, then it should be time to try out some of the chemical refinements that I've been trying all this time with poor results, owing to trying them in cells with very high internal resistances.

Zinc: Best Negatrode in Salt Solution?

   Zinc is in some ways a great battery negatrode. The reaction voltage is about as high as will work readily in water, and the oxide or hydroxide is a relatively conductive semiconductor, so it doesn't tend to become passivated.
   I knew zinc oxide or hydroxide dissolves in common acids, and I had read plenty about how it temporarily forms soluble zincate ions in alkali. The soluble forms migrate, degrading the electrode and causing poor cycle life - the bugaboo of attempts to make 1.6 volt nickel-zinc rechargeable alkaline batteries, as well as acidic ones. (My nickel-zinc in oxalic acid experiment seemed to work - none of the charge and discharge products are supposed to be soluble in oxalic acid. But that was just a short term test, and the 1.45 volts potential was lower than expected.)
   The 'known' solubility problems of zinc steered me away from it, and led to my unsuccessful attempts to make a manganese electrode with egg albumin to raise the hydrogen generation voltage - which would be a fabulous negatrode if it can ever be made to work.
   But now I read on Wikipedia that zinc oxide and hydroxide are both "virtually insoluble" in plain water at ordinary pH. This leads to the thought that ordinary cheap old zinc might after all - possibly - make a long-life battery electrode rather than one that degrades with cycling, if the electrolyte is a salt solution. This would imply that it must form the oxide or hydroxide rather than zinc chloride (as it does in ammonium chloride) as it discharges, and that the zincate ion doesn't form at neutral pH.
   I think it's worth making and trying out cells with zinc negatrodes. If it works I'll have solved a problem that many battery researchers have struggled with. Perhaps rechargeable NiMn-Zn can make the cheapest long life batteries ever, at about 1.9 to 2 volts potential. Or V-Zn for that 2.2 volts!


We can guess that zinc in salt solution will react at about -1 volt,
and that the final discharge compound formed will be ZnO or Zn(OH)2.
But will that nasty Zn(OH)4-- ion form?

A Zinc Positrode?

   There's another surprise: On going to WebElements.com to get the above chart, I note on the page that evidently zinc can form zinc peroxide, ZnO2, a substance I hadn't heard of. One way to form it is by reaction of zinc oxide with hydrogen peroxide -- which implies that it doesn't immediately discharge back to ZnO in water. But info is limited. Wikipedia has little to say, and the electrochemical charts don't show that such a compound exists - because they don't consider salt electrolytes. The three most important questions are: Is it soluble, is it an electrical insulator, and what is the reaction voltage?
   If the answer to the first two questions is "no", and if it has a useful reaction voltage, zinc might make a good positrode in salt solution as well as a negatrode. I've never heard of this before, which suggests it probably won't work or is impractical, but hey you never know - it's worth checking out.
   The obvious way to try it out is to make a cell with two electrodes of zinc oxide... the oxide is the discharged state for both electrodes.

Neg: ZnO + H2O + 2e- <=> Zn + 2 OH- @ -1 volt
Pos: ZnO + 2 OH- <=> ZnO2 + H2O + 2e- @ +? volt

   The zinc valence in the peroxide is still 2, so it must have single bonds between each of the three atoms. Interestingly, it looks like the water should be in balance charging and discharging.

More Experiments (from Oct 9th)

   Finding that the main conductivity problem seemed to be between the electrodes and the terminals, and having distanced myself from the problems for two or three months, I realized that if I could make a grafpoxy coated metal grill as an electrode substrate, I could also have coated leed wires soldered to it, eliminating the carbon rods and the graphite sheets entirely.
   Such a promising improvement was just too tempting to put on the back burner for some other time. I made too much grafpoxy (hard to control epoxy flow in x1 grams quantities), so I made several coated copper grills with various terminal wires or brass bolts. One I put into the good case (after dumping out the vanadium electrode) and sealed the hole where the wire came out, with more grafpoxy. I put the vanadium and the zinc back in, but it didn't work well. I decided it was time for a completely new cell.

   Then I wasn't looking forward to trying to put the grills with the copper wire sticking out the middle at right angles, into the compactor. But if I tried to attach them to the electrodes afterwards, they'd probably turn out like the vanadium. Then I realized making them with the wire sticking out sideways offered advantages: the compactor would take them, and the cells would sit flat with no wire coming out the bottom.
   So I made some new ones. Then I thought to simply clip the wire off some I'd already done, scrape an area of the screen in a corner, solder on a new wire, and recoat the bare areas. After that I had 8 grills ready.

New Cell

   I found an acrylic case with thinner walls that I'd made earlier, and I decided to go with that and lots of 'stuffing' to keep the electrodes from fluffing up. So then it came down to filling it. It might burst or leak under pressure. First I had to get far enough that that would matter.

   Cell Internal Components

Positive:

* Graphite Sheet

* Briquette:
10g monel mix (instead of just Ni(OH)2)
  3 g KMnO4
10g graphite powder
  .25g Sunlight dishsoap
  .2 g Sb4O6
2.75g Diesel Kleen (slightly too wet)

* Mixed. (Tamped down, resistances read around 10-15 ohms)
* Calcium oxide layer sprinkled on grill
* Compacted (with grill)
* Painted on calcium hydroxide layer


It made a 3.5mm thick electrode with no left overs.

However many hundreds of ohms the grill by itself read, the finished electrode read under 10 ohms - mostly about 5 - from random points on the surface to the terminal wire. This bode well indeed for the finished product! In fact, it would seem I could use a little less graphite, maybe about 1 to 1 by weight with epoxy, and the mix would flow better and make a thinner, more uniform coating.

   I put the trode into the case and grafpoxied around the leed hole. Later I realized I had forgotten to bake the electrode in the oven 80' at 110ºc and then torch it. Oops! Too late now.

Separator:

Microporous cellophane painted with acetaldehyde with osmium dopant
Arches watercolor paper painted with zircon

Negative:

Zinc sheet from a standard dry cell, copper foil soldered to an edge that sticks up above the electrolyte.

Figuring out the amp-hours is simple: it weighed about 5 grams, and zinc is .820 amp-hours per gram - 4.1 amp-hours. Attaining this figure, however, would mean turning the entire zinc sheet into oxide. Ideally one might use zinc and zinc oxide powders mixed with graphite etc, with an enclosed grafpoxy screen. The zinc sheet with a soldered on leed is just plain simple for experimenting.

Electrolyte:

H2O with KCl and borax



   The next day (13th), I made the usual flat cell, per above. It was very thin with only a 3.5mm electrode having an internal collector, the separator, and a thin sheet of zinc. I think the space would have held four such cells!
   The 'prismatic' cell idea comes to mind - alternate layers of "+" and "-" all tied to the same terminals. Instead of maybe 25 mA holding good voltage (as it turned out) it could put out 100 for quite a while. Put enough crappy batteries together and you've got a good one. If it wasn't for the difficulties of connecting the electrodes together in a case with electrolyte that attacks metals, I might try it. But perhaps I could solder up the connections and then coat them with grafpoxy, or even just epoxy.
   Back to the plot, I put in two pieces of 5mm ABS plastic above the top electrode to take up space. Thus there's more solid and less elastic layer, but the positrode could still swell up if it pushes very hard. I'm counting here on the problem having been more the contact between electrode and collector, which I trust should be greatly improved.
   The open circuit voltage, initially about 1.3 volts, seemed to be about 1.8 volts after some charging, maybe .4 volts lower than V-Zn.

   It seemed I could put considerably more charging current into it without the voltage getting pulled too high. After a few hours of charging, it could momentarily put out an amp of current into one ohm (at one volt, obviously). That's just 35 mA per sq.cm interface area, but on a par with my best. But my previous best cells would put out less and less over a few days. (I should have taken them apart, dried them out, and re-checked electrode conductivities then - I'd have found the problem sooner!) Would this one deteriorate as well, or stay the same? In a load test the same evening, voltage still dropped pretty rapidly with a 25 ohm load. It was below a volt after 25 minutes. But it hadn't really had a lot of time to charge yet. Again, the zinc side must have been pretty much charged to metal when I put it together, but the NiMn side didn't seem to be charged. I used KMnO4, but the nickel would have been in a discharged state and probably would have discharged the Mn to MnO2, so it might take some charging, or some cycling, to (hopefully) balance them out.
   I then opened the case. To try and increase the surface area of the zinc, I sprinkled a little zinc powder on the separator sheet, and then put the zinc sheet back on top of that. And I added a bit of water with dilute potassium chromate chloride - might improve electrolyte ion conductivity?
   I didn't see any immediate notable changes from these experiments - perhaps a slight rise in conductivity.

   The next morning, the cell started a 25Ω load test at 1.74 V open circuit, and dropped only to 1.64 after 30 seconds under load. It held above 1.5 volts for 7 minutes. Just as it appeared to be a real battery, it started dropping rapidly and by 12 minutes it was down to 1.20. Then the drop virtually ceased and it held over 1 volt to the 35 minute mark, 10 minutes longer than the first night. I attributed the rapid drop to the various charge states of the mixed manganese and nickel, thinking that perhaps overnight it had charged up a small amount of MnO4- or NiO2, and that when that was exhausted the voltage dropped to the MnO2 level.
   A longer - or faster - charge before another test might tell more. I put it on at 53mA instead of 33. But before that, I opened the case again and added some more (KCl) electrolyte and a few tiny drops of methylene chloride - this time an organo-chloride.

   I found the cell leaked - from where I'd heard a "crack!" sound as I did up one of the case lid screws. I turned it up on end. I also read that zinc gradually forms an insulating zinc carbonate layer when exposed to air, which tends to passivate it. I thought it was just oxide, the discharged state. Evidently I should have buffed it off before I put it into the cell, and the zinc powder, having been sitting in the air, would be of little use, at least initially. This could be part of the reason for performance being initially poor but improving over time.

   Whether from the charging, the additions, or both, by early afternoon the time the cell would source an amp or more into a one ohm load rose from "a moment" to about ten seconds. I'm pretty sure that makes it my best cell yet. A third load test in the evening after a long slow charge was about the same as the morning except that all the times were about 2-1/2 times longer.
   The 15th was a little better, but I added some more electrolyte and the case cracked in a couple more places. An evening test marginally surpassed all previous, but green puss - I mean saturated nickel and copper oxides - was oozing out the leaks.

   Looking in at some of the greenish substance through the clear walls disclosed the random lamilar structures formed with the black graphite when compacted with "Diesel Kleen" solvent (which seems to dissolve graphite) to provide random conductive paths through the electrode, which really helped conductivity within it - tho evidently not to the previous graphite sheets and terminal post. These are pretty much invisible when the electrodes are first made and all is black. I tentatively atribute the effect to the 1,2,4trimethylbenzene in the Diesel Kleen, but other of its chemicals may well also be involved. I'm really no chemist and especially not an organic chemist, and this is but a conjecture.



Random dark lamilae - "ribbon" layers -
of graphite within greenish oxides at 10x magnification.
(Electrode was compacted left-right in this view.)
Some areas showed more random "squiggly" black lines.
(eg, the out of focus area on the right side of the left image.)

   The maximum current into a 1 ohm load didn't go much higher, perhaps 1.3 volts momentary dropping to 1 volt after 12 seconds. A standard D cell I tried gave about 2 amps driving over a volt (.5 ohm load), and lasted somewhat longer. The zinc sheet in my cell is about 1/2 the surface area of the D cell's, and I infer that the limiting factor is the limited surface reaction area of the zinc sheet. The next thing to try (probably after making a new case) will be to use compacted zinc oxide powder in a porous electrode similar to my others. If the theory is correct, current drive may be substantially higher.
   Another thing to try will be to vary the proportions of KMnO4 and NiO2 (or monel) to see what gives the higher voltages longest before they drop to a lower level.
   And as always, to try and improve the quality of the construction. It's not much use if it leaks, the separator sheet shorts, the current collector corrodes away, etc.

   I couldn't resist doing a bit more with this cell before I got around to making another. The fifth discharge test ran out a little sooner. I figured this was because it was running short of water with the leaks, so I opened it and added some, and also a just couple of drops of toluene. (Nevertheless the wall of the case cracked in several places over several minutes next to where I'd dripped in the toluene.) Since it didn't happen immediately, I guess the toluene must soak into the acrylic and cause it to swell. It's still a pretty hard and brittle plastic, so the expanded area cracks against the unexpanded.
   Whether because of more water or the toluene, the current drive increased. Into a 10.7 ohm load, it stayed over 1.5 volts for 10 minutes. A 1 ohm load held over 1.0 volts for 30 seconds instead of 12.

Remaining Issues

   The self discharge, while now spread over hours rather than minutes as in my earlier attempts, is still too high for a practical product. It needs to be slowed to days if not weeks. Months would be better.
   Current density could be better, tho it's already not bad. The electrode surface interface area in my test cell is about 25 sq.cm. - half that of a simple D cell. The max current of 1.2 amps into a one ohm load gives: 1.2A/25 sq.cm = 47 mA/sq.cm. To maintain good voltage however, the current density is at best around 20-25 mA/sq.cm. of separator. That's in the right ballpark - around that of a standard dry cell.
   Calculating this out surprised me - I thought an amp max was pretty poor, but it's mainly because the cell is small. The case is after all mostly filler and the battery is a thin layer on the bottom.
   However, attaining the 40-50 or more achieved by alkaline cells - or better - would be nice. (A zinc-air cell has the best figure I've seen: 200 mA/sq.cm.)

   I have yet to determine the theoretical energy density. I have little doubt it's higher than lithium ion, but nothing like that is being achieved at the moment. In this cell, the zinc sheet needs to be replaced with a proper powder electrode, as only its surface layer gets used, giving a whopping .1 AH or less at ever decreasing voltage. (Other batteries I've made have given near an amp hour, but at very low voltages. In the standard dry cell, the surface of the zinc is continually eaten away by becoming soluble zinc chloride, so much of the zinc sheet is gradually used. That's why it doesn't recharge well. Here we form insoluble zinc oxide at the surface, and the thickness of the sheet behind it is unused.)

   The grafpoxy grills work! They are the great enabler for salty battery chemistries. I think a new cell with two proper electrodes and (sigh!) no leaks is the next step.

Real Zinc Negatrode

   On the 20th I decided to make a "real" zinc electrode and stick it into the same leaky battery cell.

20g calcined zinc oxide (13 amp-hours worth)
5g graphite powder
.25g Sb4O6
.25g Veegum (bentonite clay mix - binder)
4g diesel kleen

   Tamped down in the mortar this was around 50 ohms. It was something of a pliable putty consistency, but there was a bit much diesel kleen and over 5 grams oozed out of the compactor. That left something like 11 amp-hours potential. That would depend on very thorough utilization, being able to get the electrodes into balance with charging and discharging, and that the other electrode has at least the same capacity.

   Then I looked at the leaky, cracked battery case and decided to make a new one and to try to pull the positrode out intact and reuse it. I broke off the sides, but when I pulled at the positrode, it fell apart near the terminal wire. The rest of it seemed hard as a rock - an excellent electrode briquette. I had noticed, on close inspection, small bare areas of copper or solder showing on all of the grafpoxied grills. Many of them were in fact next to the terminal wires. (Perhaps remnant solder flux kept the epoxy from adhering.) It doesn't take much of a bare spot - corrosion will rapidly spread until the cell quits working.
   Grafpoxied grills are doubtless still the key, but it might well pay to use less graphite to get better flow and smoother coverage, even tho the conductivity would be reduced. It might also be necessary to do two coats. Rinsing and brushing the grill after soldering might also be valuable - or even some exhaustive cleaning process such as those used before electroplating.

   So I made another positrode as well, out of about 25 grams of Ni(OH)2 and KMnO4 mixed last January. I didn't do much measuring. I added too much diesel kleen as usual. This time I forgot to add anything as a binder - I had meant to put in a bit of Veegum. Instead I remembered both to put on calcium oxide and to torch it this time for the 'limestone' toughness. Sigh - seems I just can't remember everything. Trouble is I make electrodes so seldom amongst all the other projects, and it's often not obvious if something's missing or a step has been skipped... okay, I've written up that checklist I've been meaning to make and taped it up inside a cupboard door.
   The zinc electrode, puttylike before compaction, proved unexpectedly crumbly and had lost some of its substance by the time it was seated in the cell.
   The cell didn't finish charging - it hardly lasted a day. The copper grill dissolved into blue powder and the electrode fell off. The grill from the first cell, however, seemed largely solid except near the terminal wire. There was a blueish tint to the briquette right next to the grill wires, but that may have been the electrode's nickel/monel substance charged to oxide or hydroxide rather than copper oxidizing from the grill. (It would be helpful if copper and nickel oxides weren't virtually the same color!)

    On the 25th I made some new grills, clamping flat pieces of copper foil (garden shop?) over the copper grill (Opus Framing - artists' supply, where I also get the graphite powder and the Arches watercolour paper) with small rivets (Tandy Leatherworld).
   I used 1 to 1 mix of graphite to epoxy. After setting the epoxy in the oven at 65ºc for an hour, while preserving the remaining epoxy in the freezer, there were some small spots of bare copper visible, and I went over them with a second layer. Close inspection with the angles and light right the next day revealed there were still some tiny bare spots.
   Much as I wanted to get going and put a battery together, they would still dissolve, so I mixed some more grafpoxy and went over the spots with a paintbrush. With leftover grafpoxy I went over copper spots on a few of the previous grills as well. In the end it was four applications. Then there was too much grafpoxy on some of the terminal strips and they didn't fit in the compactor. I carefully filed some off, but struck copper both times and had to do yet more grafpoxy. Then, with the terminal strips and all the grafpoxy added, only one of the grills fit in the compacter.

   I'm wondering if something else might substitute for the epoxy. "Grafwax" might work well: melt the wax, mix in the graphite, and then just dip in the grills. But wax is pretty soft and surely wouldn't withstand compacting the electrode around it. Maybe some plastic that one could melt and dip the grills into? But that doesn't seem to exist.
   A dip of ABS dissolved in methylene chloride and mixed with graphite? Ugh! Hmm. It might work. At least it's harder than wax... and more flexible than cured epoxy.

   And just for variety, I have a little of the #60 stainless steel grill left, and some aluminum window screen. As long as it's protected and clamped to the terminal with rivets, it shouldn't matter very much what type of metal the grill is. The fine stainless mesh should give the most contact points with the electrode substance, which might perhaps provide higher current capacity per unit area, especially with a thin electrode - unless the grafpoxy plugs the tiny holes.

   I took the remaining Monel-MnO2 powder made in April (27g, TE News #39) from the back of the counter and added 8g of KMnO4 and 5g of graphite, total 40g. Then I added 5g of diesel kleen and compacted it. It made a fat 6mm briquette, and the resistance was 15-20 ohms from any surface point to the terminal. (Pretty amazing when the layer of grafpoxy left over on the plastic sheet measures 20000-100000 ohms!) If the grill doesn't dissolve, it'll be a great electrode - good current and surely over 10 amp-hours capacity.

Carbon Nanotubes

   Evidently carbon nanotubes help a lot with increasing conductive surface area at the nano scale, increasing the efficacy of the active elements. Reading in Wikipedia/Toluene (methyl benzene): "[Toluene] is used as a solvent to create a solution of carbon nanotubes." Perhaps if one simply added toluene to an electrode with all that graphite in it, carbon nanotubes might be formed as it evaporated? So this time, rather than adding it to the electrolyte, I dripped a few drops of toluene onto the electrodes before putting them into the battery, and left it to evaporate. Of course, I don't know if that will actually work... but it probably can't hurt anything.

   The battery didn't perform very well and gradually got worse. I took it apart at the end of the month, and this time it was the zinc negatrode grill that seemed to have degraded. This I had salvaged from cell #2, and there were doubtless gaps in the grafpoxy. I also think if I make and use some zinc powder (and keep it sealed this time so it doesnt form zinc carbonate) it'll work better than just using zinc oxide.
    The electrodes slid out more easily through the open side and could then be separated easily. This is definitely a better case style. I'll be putting it back together with a new zinc side in November. But I went to get more 1/2" acrylic plastic and some 5/8" and 3/4", but they only had 3/8".

   I'll also be trying out some more electrolytes in November.







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