Craig Carmichael - January 2nd 2009
December in Brief (overview... summary... the short version!)
* or, this TOC is the Super Short version...
* December was a slow month for the energy projects.
Electric Hubcap Car Drive Project, Longwinded Detailed Report
* Cold weather, flu delays production model prototype tests.
Turquoise Battery Project, Longwinded Detailed Report
* To get much lower resistance, more current: compress powders.
(nothing established battery makers didn't already know!)
Electric Hubcap Motor Making Course/Workshop: Hybridize your car (or other relevant motor project)!
* Workshops are on hold pending motor road tests - (Hopefully coming this spring)
The changes about
to sweep the whole face of transportation were delayed a bit longer this
month -- just that little bit longer before the day the Electric Hubcaps
and Turquoise Batteries can come "on sale" in a Canadian Tire
flyer to be whisked off by those still driving on gas.
There were no failures, burnouts or design problems to rework. Indeed, the "production prototype" motor was completed and tested on the bench. But after a year of concentrated R & D efforts, December's pace was definitely reduced.
I salvaged some supermagnets
off a couple of rotors to make a new 10.25", 18 magnet rotor. That took
a couple of weeks waiting for vinegar (and then Draino) to soften
long hardened epoxy glue.
While that was happening seemed to be a good time to get to some other things that were being neglected. There seemed to be lots of time to get the car running sometime during the month. I fixed my electric sawmill motor which had been busted since September and milled some logs that should have been cut by fall. Then cold weather set in... and stayed... and stayed. Perhaps it set some records for Victoria. I began to think I had somehow moved to the prairies. Then I got the flu.
With an unheated workshop and the thought of working on the car outside in the snow being unappealing (even before the flu), the cold weather seemed to be a good time to concentrate on the batteries. I did some research, and found an excellent nickel-zinc alkaline battery writeup where dozens of experimental variations had been tried (a patent from Sanyo, 1999). A customer that bought some Pacific Dogwood sent me his masters thesis, on making thin film lithium batteries. (Gosh, the last guy who ordered dogwood was a retired biochemist who had also once experimented with battery making!)
Most importantly I figured out why my batteries have such poor current drive: regardless of chemicals, the powders are too loose and so the granules are making poor connection with each other. More strongly compressing them, as in using some sort of press and mold, should provide perhaps an order of magnitude better current capacity. A first attempt shows promise. Best wishes to all for the new year!
The Electric HubcapTM
Vehicle Drive Motor
December Gory Details
Production Prototype Electric Hubcap Motor
Left: Magnet Rotor Disk - spins, bolts to car wheel's stud bolts
Middle: Outer Housing, a plastic culvert pipe
from which "Turquoise Energy Ltd." derives its name.
Right: Stator Disk (blue), trailer hub & axle
Bottom: the 3 heavy power wires, optical commutator cable.
Some Physical Dimensions and Specs:Diameter: 13" (about 11" plus wiring, case.)Length: 7" (shortest trailer axle is 6")Weight: 46 #.Volts: 36 (nominal battery voltage)Amps: 100 (this and below are very tentative estimates)Watts: 3600 (in)Efficiency: 95%HP: 4.6 (out)RPM: 0 to 1500
Theoretically, the motor could be 11" diameter by under 3" long with custom rotors, hub and axle and no need to fit it to a car wheel. Actually the length as shown is about 8" -- the magnet rotor is sticking out an extra inch for the photo. The plastic housing will be all but touching the car wheel to keep dirt out. (Stator mounting arms aren't installed yet in this photo.)
When I found a
disk brake rotor (a Honda car rotor) that fit perfectly on the trailer
hub, that solved one side of the motor perfectly. The trouble was, that
same type of rotor didn't quite fit my car wheel. The original rotor fit
the wheel but was a smaller outside diameter. Obviously, every car is going
to be an individual fit.
My first thought was to machine a bit off the corner of the central hub when I get the metal lathe. But, hey, as there seem to be an almost endless variety of brake rotor sizes and shapes, why not search around until I find the "perfect" one for Toyota Tercels?
On the 27th I phoned a brake place to make sure they were open Saturdays. They were, so set off with steel toed boots, gloves and a ruler to search the bins. Well, that place was open Saturday. They didn't have one the right size, and most of the others were closed. That's what I get for trying to shop on a Saturday!
Monday I tried Wade's auto wrecking. Unfortunately, there simply didn't seem to be a better fit after all. There were a lot more variations of sizes for five lug bolt rotors than there were for four. But that would mean trying to drill exact new holes that overlap the original holes in order to match the four bolt pattern.
I guess I'll be grinding or machining to fit after all!
Advantages of the Electric Hubcap Design
Someone sent me a link to Michelin Tire's Electric Wheel. It's always interesting to see what others are doing. I don't spend much time looking for myself, so it's nice to be pointed to some of the most interesting stuff.
After viewing it, I realized that with trivial changes, the Electric Hubcap (already made of automotive and trailer wheel/axle parts) could itself be a Motorized Wheel, ready to install on a new vehicle, somewhat like Michelin's product except using external suspension. Brake pads would be situated on opposite sides of the (unused) outer face of the magnet/brake rotor. It would need 14+" wheels for the rim to clear the motor coils. It's not a market I'm considering attempting to tap any time soon. However, custom electric vehicles is a potential use of the Electric Hubcap. One EH should power any sort of lighter vehicle on pavement.
Michelin's product is a big wheel (18"?) with a very high power motor. It's being used in some novel sports cars. The mounting position indicates that the motor drives a big ring gear on the rim of the wheel. Makers often call this "direct drive", but like other drives it's well geared down to multiply the torque so the motor with its lesser torque can turn the car wheel and move the car, which takes a lot of torque. Figures given indicate about a 7 to 1 gear ratio. I can't tell from the picture or from the descriptions I saw whether it's a typical induction motor or a PMSM.
Michelin Tire's Electric Wheel. Their complex offering includes "active suspension" built in as well as the geared drive motor on the right. It looks impressive and has some impressive looking specs - but is it best? The connections seen would be for power, brake hoses, mechanical attachment, and liquid cooling hoses for the motor.
I took the opportunity
to sort out and write down what the EH has over other electric vehicle
drive motors, including this one - some of which I only gradually came
to realize myself once I was working on it.
Once we humans get used to seeing something and doing it a certain way, that becomes familiar and other designs and techniques seem "alien". Any attempt to change it beyond expected "normal design parameters" will meet with objections from "experts", who will tell why it will fail -- why it is impractical if not impossible. They understand in fine detail the familiar design but don't quickly see that changing that design changes the fundamental rules on which their objections are based. Yet, often the "familiar" isn't the best - it's usually just the first way that gave decent results somewhere back in history when the idea was first being developed. (All the electric motor books I've found date from the 1930's or earlier.)
The Electric Hubcap motor was made possible by abandoning the familiar radial flux motor layout - and also much familiar "normal design" which is actually peculiar to that layout - for axial flux, and facing the untried and unfamiliar challenges of designing and constructing such a motor. Unforseen advantages and a surprising robust simplicity gradually emerged from the trials and errors of trying and doing. (Considerably more gradually than I'd expected!) First, the axial flux layout gives it the short "wheel hub" or "hubcap" shape to sit within or on the outside of a wheel. A radial motor would stick out a foot or so beyond the fender - it would be impractical.
PMSM has much more low-speed
torque than a similar size induction motor, and the Electric Hubcap has
much more torque again with the axial flux layout giving a much larger
diameter and making room for bigger (and better cooled) coils having no
wasted copper and more useful iron.
One might almost say it runs an order of magnitude slower than "typical" electric motors, and has an order of magnitude more torque. These are the torque and speeds other motors are geared down to achieve.
The individual motor efficiency increases over "typical" electric car drives are small but but they are several and cumulative:
It's said it takes 10 HP to keep a car cruising along a level highway. If the EH takes 40% less, that's 6 HP. That's on the edge for one wheel, but two of them should be sufficient. The high torque should give it more acceleration at lower speeds than similar power rated gas engines, so it should handle hills in town okay. What speed it can maintain going up the Malahat with two is reserved for the trials. For a lighter vehicle not weighted down by a combustion engine, surely one motor would be plenty for normal driving.
The Electric Hubcap is a compact, dead simple, practical, 50 pound motor. The figures, even as rough estimates, are compelling. The more it's considered, the more apparent it is that this is the future of vehicle propulsion.
The big, heavy combustion engine connected to a clunky, inefficient, mechanical transmission suddenly looks like a primitive dinosaur. They sell by default so far, but they are ripe for sudden extinction in the new car market, though many new vehicles will likely retain some smaller petrol engine driving a generator to power the electrics on long trips. The switch is inevitable, but the EH motor concept holds the promise of best economy and value for it in every sense.
Better batteries would of course also make a very big difference. Batteries that would power a long day's drive could lead to overnight charging stations on highway routes, especially for example at motels and campgrounds, and a complete end to common use of gasoline in vehicles.
Turquoise Battery Project
December Gory Details
Finally I took a punch
and die set normally used for cutting sheet metal disks, and filled one
of the dies with nickel hydroxide. Hammering down on the punch compressed
it from 15mm tall to 5.8, with a density of about 1.9. Furthermore, it
went from being a loose powder that would fill the air if you sneezed on
it to a brittle solid object much more like the actual battery electrode.
At that point, it was obvious that has been a big part of my problem: although the literature speaks of "powder electrodes", powder per se is too loose to make a good electrode with good electrical conductivity unless it is very much compacted.
Apparently the densest thing around is me, for having been ignoring the figures I was reading and their implications.
I have no doubt that once I've set things up to compress the powders, I'll obtain at least an order of magnitude better current capacity -- and start having batteries that work in practice as well as in theory.
I had an idea for making a rectangular punch and die to compress the powders, but it suddenly occurs to me it might be simple to make some jig and compress them right onto the collector plates using my rolling mill. It's the one piece of equipment I have that's made to exert that kind of compressive force.
Nickel Hydroxide Powder Compressed to 1/3 its original volume.
It should be denser yet.
Here's a first try at making a punch & die type powder compressor. It makes 1" x 1" squares, here of soap-wetted nickel hydroxide. I don't think it got to density of 2.0, but it's above 1.5. (I don't have a scale to weigh "ones of grams" very accurately.) In front is my latest electrode separator sheet... a few thicknesses of non-woven polyamide "fusable web" cloth.
Then there's chemistry. I finally decided I must have a mental block against acid electrolyte. There were a number of things that were suggesting it should be tried. For one thing, I haven't found tetravalent lanthanum on the web, but lanthanum is next to cerium on the periodic table and cerium needs acidic - the voltage runs the other way entirely in alkali. For another, if I'm going to use ion passing membranes, it seems more likely that something like cellophane will pass tiny H+ ions (AKA lone protons, obtained in acid solutions) freely than big OH- ions (obtained in alkali solutions). (Think how helium leaks out of a rubber balloon much faster than air - oxygen and nitrogen, and helium is much larger than hydrogen ions.)
To turn the perchlorate into perchloric acid simply required adding sulfuric acid to the mix. (No, I don't know how to do these things offhand - I look them up on the web!) I added about 4cc to 40cc of electrolyte. When I added the acid, the liquid started to bubble up from the bottom -- to "percolate".
Battery in a transparent plastic tube. All the strange fluff that has formed with charging is supposed to increase the conductance of the battery for more amps, but it's not working right at this point.
Perchloric acid is so
acidic it's called a "superacid". The PH read as "2" on litmus paper. I
decided that was just a bit much and added potassium hydroxide solution,
KOH, to bring it up to 3:
|KOH added||PH reading|
|2cc||1 (good grief!)|
(And to think me and my partner Werner
used to "ace" all our chem labs in high school! Must have been his doing
There were no certain results apparent. The internal resistance remained very high as in the other tests since putting cellophane around one electrode.
One soon manifest result was much lower pressure - about 10 PSI. I'm not sure what it got up to before, but it was probably 40 or 50 and climbing.
About the end of the month I looked up cellophane. It turns out that although cellophane is normally permeable to moisture, special non-permeable types are now common. Great, I'll bet I have the wrong stuff! That would explain those high resistances.
I also ordered a Kg of dysprosium to see how it would work and what the voltage would be. I'm expecting Dy-Zn cells might be around 3 volts. (...or is it just wishful thinking? If the Dy reaction voltage is too high, it might well not work at all.)
I found the reaction I'm looking for, for a lanthanide with perchlorate, forming perchloric acid, HClO4. It was given for cerium (Ce in three acids), so I can only guess the voltages for lanthanum and dysprosium. These areas evidently aren't very well explored: in all this time looking at reduction/oxidation formulae I hadn't run across it before for any lanthanide; the same site lists nothing at all for dysprosium.
Ce(ClO4)6-- + e- <==> Ce+++ + 6ClO4- [+1.70 V]
(How all those ions can move just one electron I'm not sure, but it appears to balance!)
Ions floating around in a liquid solution are likely to leak and-or to build up, as in zinc ions building "dendrites" towards the electrode separator sheet as they turn into crystals of zinc metal during charging.
The purpose of the Sunlight dishsoap (it has several interesting chemicals in it), monel and lanthanum hydroxide burned in bean sauce, polymerized acetal ester, and agar agar gel, are to solidify or gel the electrodes and chelate the metalic ions so they don't move around even when they change form with charging and discharging. The zirconium silicate powder sprinkled on the zinc electrode is a dielectric to change the pattern of crystal growth and eliminate the tendency to form dendrites.
I think that should pretty much solve the problems of limits to battery life, usually caused by accumulation of small displacements until something goes.
How Rare are the "Rare Earths"?
elements", atomic numbers 57 to 70, are each unique but share some common
characteristics. In general - and like aluminum - they react with water
and oxygen, so they are never found in pure metalic form in nature on our
planet. Hence when they were first isolated they were believed to be rare.
Today the most common ones are sold as ingots by the kilogram, not by the
gram. They are often found in ores together, so they are first separated
as a mixed group called "mischmetal" and then usually into individual elements.
Unlike lead, cadmium and mercury, they are not considered to be toxic.
To generalize, they get less common with increasing atomic number, and also the odd numbered ones are much less common than the even numbered ones beside them. A good part of the cost is for separating them from other substances and then from each other.
The most common ones, lanthanum (57), cerium (58) and neodymium (60), are about as abundant in the Earth's upper crust as nickel or copper. Dysprosium (66) is only 1/10th as abundant, but still perhaps 50 times as abundant as silver. (And, it has no other special uses I've heard of, so there should be plenty for all the batteries anybody wants!)
AFAIK they're all a silver color and can be mistaken for other more commonly used metals. I've seen some of them described as "Soft, can be cut with a knife." I must observe here that copper, brass and aluminum are also "soft, can be cut with a knife." I had to use an angle grinder with a cutting wheel to dissect the lanthanum ingots. I think it was considerably harder than brass.
First Proposed Class - WorkshopThe fact that the "production prototype" Electric hubcap still hasn't been road tested keeps us in suspense about how many of them it will actually take to acceptably run the car, an important point of planning for the workshops.
* Instruction session: working principles of the Turquoise Energy Ltd. Electric Hubcaptm vehicle drive motor and its ancillary components, as applied to creating a plug-in hybrid car and other useful applications.
* Motor making workshops as required to assemble the motors.
* Instruction session: motor controller details; simple controls details.
* Workshops: assembling the motor controllers and wiring boxes, and the simple controls.
* Instruction session: various aspects of installing the motors, and the computer controls.
* Motor installing workshops as required to get the cars going.
*Additional instruction and workshops as required to complete projects.
* Followup session(s) when computer controls are complete: install computer controls.
Participants should be mechanically inclined. Experience with design, fabrication and installation in any fields of metal working, mechanical, auto mechanics, electrical and electronics are assets. Participants are encouraged learn principles of construction during the workshops and do work on their own if and as convenient. Work will be inspected and discussed by me and by the other participants. Creative thought in adaptation to specific vehicles and improvements to systems is encouraged.
The object of this course
(a) to have the participant create his or her own Electric Hubcap equipped super efficient plug-in hybrid vehicle or other similar motor installation of choice, and
(b) without obligation, to provide a trained nucleus of people to who are familiar with this exciting and promising new technology, the future of propulsion. They'll not only save on gas, they'll be engaged with the cutting edge of electric transportation technology.
I haven't specified the number of workshops for each phase: there's lots of new things here and it's hard to quantify how long the jobs will take. We'll continue for one or as many sessions as it takes to satisfy the class. Installating things in the car is the most time consuming part, and is likely to vary considerably by vehicle.
There'll be three instructional manuals (or subjects in
one large manual) to accompany the workshop: Making the Electric Hubcaptm
Motor, Making the Electric Hubcaptm Motor Controller,
and Installing the Electric Hubcaptm Drive System
in a Vehicle. Writing of these proceeds apace.
The tuition fee for the workshop program will be $1950 (maybe less), and the parts cost will be $900 per motor. That includes most everything: the motor, controller, wiring box, and cables. But (what else is new?): batteries not included.
I think I should order/buy the parts, paid for in advance by the participants (at cost - but see below). That should bring some quantity discounts, and the materials would all be on hand when the workshop sessions commence. Perhaps the money for materials (as well as the tuition fee of course) can be made tax deductible and PST exempt - that would lower the costs for participants.
I was surprised the materials for each complete motor installation cost so much when I added them all up. Anyone who wishes to provide some of the supplies themself is certainly welcome to do so. I will of course need to know what you are bringing before I order the parts. Particular items to provide that can save money are listed below.
Particular items to provide that can save money:
* car disk brake rotors - Honda Civic(?) rotors (10.25" diameter with
a hub of 5.5" inside diameter) appear to be ideal for typical 4
lug bolt wheels. Discount: $75 per motor. Anywhere that does auto brake
repairs should have used rotors going into the garbage can. They don't
have to be in great condition, though a pretty flat face to mount the magnets
on is desirable.
* winding and varnishing/baking your own coils: Discount $100 per motor. Count on spending a couple of days or more doing them. (Otherwise I'll make them before the course starts.)
* Finding your own heavy copper wire, 200 amp circuit breakers, motor capacitors (3 x 7uF 120+VAC "run" capacitors, 3 x 100uF 120+VAC "start" capacitors), wiring boxes (preferably aluminum for heat dissipation) and other electrical parts. Heavy #4 battery cables and #6 "cab tire" cables to the motor cost several tens of dollars per motor. 200 amp breakers for the motor controller boxes (preferably aluminum boxes for heat dissipation) all add up. Discount will have to be determined when the parts are known.