electric TC gearing Question

[Plaidfish]

I recently got a TC4 and have been using it at a local track.....my problem is I have tried the stock spur gear ( I was told that was the best gearing) w/ a 25 / 26 / 27t pinions.....all are generating alot of heat from the motor....the last try was the 27t pinion and it seems to have melted the casing on my ESC (intellispeed 8t pro forward only).......I've never seen an ESC heat up before a motor just fried......but this was obviously from the esc heating up since it (the melting) starts from the heatsinks.....the ESC still works fine but t his is definately not acceptable running conditions......I'm using the orion 4800mah lipo batt pack.....before I ream duratrax out over the thing not shutting down (like the thermal protection should have done) I need to know the answer to this question:

is there ANY correlation to gearing based on the capacity of the pack?

I purchased this ESC based on their outrageous claims of peak current at 4700AMPs....not miliamps but AMPs......the battery never got hot but teh motor did.......is there a temperature I'm supposed to be aware of on electric motors? and does anyone have that generic gearing chart for TC4? I had it for the TC3 but I just want to make sure it's the same for both....if it is I'd like that again as well.....
thanks

 

[Candyman]

OK, disclaimer----I don't run electric, so I'm just going on theory here.

If your ESC is overheating and the motor is stoking hot, I would be inclined to think you're overgeared. Drop a few teeth on the pinion or add a few to the spur.
I would be concerned about the ESC, though. If it can handle 4700 A (still not sure that's right), it shouldn't heat up. If you were anywhere near 4700 A, you'd have toasted the battery and motor long before. I'm guessing your LiPo is good for 10-15C. So it can juice up to about 72A before it starts to get in trouble. If your ESC is melting down but the battery is cool, I would think there must be something going on there.
I wonder.....for airplanes they have a "Wattmeter". You hook it up in line with your power system and it will give you a readout of current and voltages under load. It lets you see if you're pulling too many amps from your batteries or exceeding your ESC rating. It's also used to maximize your prop selection. Anyone in electric racing using something like that? I bet it would help a ton when gearing the car.

 

[sweetdiesel]

With lipos, increasing the capacity (mahs) will increase the maximum discharge current. For example: a 15c 1000mah pack can discharge at 15amps, while a 15c 4000mah pack can discharge at 60amps.

Is there a lot of heat from both the motor and the ESC, or just the ESC? General rule of thumb from what I have read is:

Hot motor, cool controller, cool batteries = undergeared
Cool motor, hot controller, hot batteries = overgeared

 

[Plaidfish]

the problem (I thnk)is they are both getting hot but the battery is cool as ice....still took a full charge......and the ESC is still real punchy.....no thermal cutoff going on.....the LHS has fallen off since the local electric guru left and I have noone who really just knows this type of stuff to help out on hand......I didn't check the ESC for heat but after running it sunday I put it up....I took it down to show my track buddy and he noticed the brand new ESC case was all warped and around the heatsink is real bad on 2 fins, like that's where it started from....it's not that close to the motor to where it could be radiant heat as well.....this is rather extreme in my opinion but I'd really like to see what gearing is recommended for a setup like this before I start pissing more cash into gearing I won't be able to use....here's what it ended up like after one pack of running on sunday.....

 

[Plaidfish]

anyone have the gearing chart or a link to it...please

 

[sweetdiesel]

Hope this helps.

http://www.gearchart.com/index.cfm?fuseaction=chart.create

 

[Plaidfish]

interesting site SD but I didn't see what I was looking for per say.......I'm looking for the chart that recommends what gearing to use with different motors...I know I saw it on here but I can't find it in any searches.....also if anyone know's what temps I should be getting out of my motor and esc I'd appreciate that info too...I know I've seen some of the guys temping their electrics at the track but I haven't been able to get there lately to ask.....

 

[Plaidfish]

anyone????

please.....