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[protomech]

I guess my only question would be, if the motor's getting warm, don't you imagine that the controller and the batteries are also working pretty hard? If you add a way to keep the motor cool, you might just move the heat stress to another part of the system. Granted, those parts of the system should be able to protect themselves too, but it's just a variable that the engineers didn't design into the system, and it might not be obvious what all of the effects might be.

They are working hard, but all three systems (motor, controller, battery) are thermally monitored and can throttle back power as needed.

I wouldn't say it wasn't a design consideration - the motor controller, for example, has a large heatsink mounted on it for cooling - but it's certainly true that as soon as you eliminate one weak point in the system then you will expose the next (slightly stronger) weak point.

[trikester]

I've found that it is my motor that is the heat problem. That is where the most power is being dissipated. I think the controller is more efficient than the motor at any given current level. It makes sense because the controller is comprised of switched MosFETs while the motor has copper windings. It is easier to reduce the "on" resistance of the MosFETs (bigger FETs) than the winding resistance of the motor.

Maybe we should insists that Zero wind the motors with pure silver wire to reduce the resistance. Oh, and we could also ask them to form the heatsinks from diamond, the best conductor of heat. Can't understand why they don't take my suggestions.

Trikester

[NoiseBoy]

Trikester, its very common to use water sprayers on intercoolers. The finer the spray the better and adding alcohol improves evaporation further.

If you fancy a project you could try CO2. It would give you very rapid cooling for short bursts.

[trikester]

Yeah, CO2 would work well but difficult to replace in the boonies. Distilled water can be found in supermarkets and if out in the boonies, streams or springs can supply an emergency supply of water. The dissolved minerals would not pose a problem if only used once in awhile.

If I were racing (like Pikes Peak) I might consider CO2 since it is a one time, brief, deal. Although I would have to determine the stress effects of such quick cooling on the outside while the motor is still generating quite a lot of heat inside. It could cause the gap to close and magnets to drag and destroy the motor. Actually with CO2 one could consider injecting it directly into the interior of the motor so that the cooling was more evenly placed. That might work quite well! Then the exiting CO2 could be piped to the controller heatsink even if the CO2 had absorbed a lot of heat going through the motor it could still carry heat away from the controller heatsink.

I think we could come up with a lot of ways to cool the bike power components for short, high use, periods of time. My water bottle solution was something I quickly supplied myself with in the very small town of Big Pine CA (one small hardware/grocery store). BTW - I did this on my e-trike but it would work as well on my FX.

Trikester

[LiveandLetDrive]

The copper's definitely designed for free-convection with very low flow rates.  I have gigantic radiators on my PC which is water cooled with no fans to similar effect.

Yeah I'd say black is more going to absorb the solar load for any components in the sun than help significantly radiating at our component temps.

Very interesting about flowing gas through the motor housing.  Anyone know if there's any grease or anything in there that would get blasted out?  You could use air if you could dry and clean it and keep it weatherproof.  Could be easier than going liquid cooled.

trikester, are you allowed to tell us anything about Hollywood's liquid cooled motor?  Is it just a jacket that replaces the heat sink piece?  As you point out having a huge thermal gradient could cause things to crash so we should keep that in mind.  I've never sprayed mine as I was worried about cracking it but that's cast iron engine block thinking, probably not as likely with aluminum.

When I went to my first Supermoto trackday I rigged up two computer fans to run off the 12V power outlet and stuck them on the motor between sessions which cooled them nicely.  Didn't take much flow, it just has such poor cooling from the factory that any little bit makes a big difference.  Cooling enough to keep up with max power draw (>80mph or continuous hill climb) might take a stronger flow.

EV thermal and CFD are my job and I've been wanting to do something with my FX but having just had it off the road for a month upgrading the suspension I don't want to pull the motor quite yet!  Anyone know how much a motor costs?  If it's less than a grand I might get one to experiment with...  Very interested in digging into this, it's my biggest remaining issue with the bike now that the suspension's up to snuff!  (:

[protomech]

IIRC it was around a grand. Check with Zero.

[trikester]

Sorry I wouldn't be at liberty to say anything about HE's liquid cooled motor but maybe Harlan would be willing to tell something. I'm sure he is working on the next generation cooling method so maybe he would be willing to tell about the present generation which still had some flaws (no surprise there).

I think that the requirements for cooling on something like the PPIHC race can be quite different than requirements for a sustained high speed highway ride or a slow steep dirt climb like I have been faced with. If I was just planning on the PPIHC (which I'm not) I might just pump distilled water (non-conductive) through the motor and blow it out onto the controller heatsink, a one time, non-recirculating, short term method. Jeff made the climb in just under 12 minutes so there would have to be that much time's worth of water supply, at whatever rate it was being pumped. Probably a good idea to add a rust inhibitor to the water,also.

Battery temp is also a potential problem on something like the PPIHC race. Unfortunately it is far more difficult to cool the battery pack since it is a large enclosed mass. 

Trikester

BTW - Harlan, are you following this thread?

[RNM]

What about oil cooling? read ˜4 posts after this one:
http://electricmotorcycleforum.com/boards/index.php?topic=4424.msg29049#msg29049

"simply filling the motor slightly less than halfway with ATF almost doubled the continuous power output. "