So I was trying to categorize my batteries by max current output...I just added a big load and watched how many amps it pulls... however my old nimh and nicd packs just couldnt match the load, Voltage dropped below 5v and my amp meter resets.

So it seems I need a variable load (heavy variable resistor / potentiometer) so I can hold Voltage steady... however I don't know what the minimum voltage is used when determining max current rating. Is it 7.2v? 6v? 5v for minimum radio operation?

Also looks like I've already maxed 190amps so I guess I will need to get another and wire in parallel. Though 5.8KW kind of sounds like BS to me :/ motor was only rated under 700 watts...

What kind of power source are you using to get 65V (or more, zip tie might be covering some digits)?

For the safety of the battery and to avoid LiPo cutoff on the ESC, I'd try to stay above at least 3V per cell.

I was confused about the 65V thing too... I suspect that was from regen braking. That was just using a cheap 2s ebay lipo (5400 @40c)

I turned off voltage cut on the ESC for the stick packs... and they are slooooooow. I'm guessing they were losing almost all voltage at about 10 amps. I could re-try with external power for the meter... though it seems the load is practically a short circuit for the stick packs... so thats probably very bad for them :/

I could use slower motors for a lighter load... though it seems like too much guess work and would be easier if I aimed for a consistent min voltage?

Ok, so I guess with a flat nimh/nicd pack is 0.9v per cell, so I suppose in a high drain condition, you wouldn't want it to go below 5.4v, correct?

So having said that, how does one build a CV (Constant Voltage) discharge circuit? Probably not too hard with a few lightbulbs in parallel with isolation switches... though I'm not sure the discharge rate would be linear... so I am guessing some kind of digital control would be needed?

It sounds like you are actually verifying the true "c" rating of your battery packs. The more common method for what i beleive you are after would be how we did it back in the day. Pick a constant load close to what the amp draw of your motor is. Then discharge each pack and record the voltage at regular intervals like 10-30 seconds. This would give you decent information for batteries under race conditions.
Thats how we did it with nimh way back when . i tried it using the discharge rates of nimh for my lipos....what killed a nimh in 5 minutes took like 15 minutes for a cheap lipo...
Chargers with IR meters might be helpful for you too.
Anyways...food for thought i guess.good luck.

I suppose that may have to be a compromise I'll have to settle for.

I will try a bunch of head lights, blinkers / brake lights etc until I find a suitable current draw per voltage drop and just plot the data manually like you said every 10-30 sec. Looks like I want to stay above 1.15v per cell according to the datasheet below?

Would you guys know where I can get datasheets for tamiya cells too? I also have a 2x orion and 2x venom packs... though something generic like this serves as a good starting point I guess.

http://docs-europe.electrocomponents...6b811db0c6.pdf

30A continuous is pretty damn weak by todays standards lol