Powering RC Hobby Motor with Integy 7.2V Battery

[jjohnson54]

Hello all,
I have a Integy 7.2V 1600mah battery that powers a RC hobby motor. I was wondering if RC batteries supply constant voltage to the motor for a certain amount of time before they start dieing or if the battery voltage continuously decreases as you power the motor until the battery dies.
Thanks.

 

[schip666!]

I googled "nimh discharge curve" and got a lot of pretty pictures, where the first was this: http://shdesigns.org/batts/battcyc.html

I'm a little surprised because I thought Nicads had a sharp drop-off, but NiMH (as yours appears to be) seem to have an even sharper death drop at the end...hmm, actually here's a better page: http://www.powerstream.com/AA-tests.htm that compares them to regular alkaline non-rechargeables. NiMH have a flatter use curve but die much more suddenly than alkalines.

 

[mheslep]

The discharge curve (voltage vs. time) also varies of course with discharge rate. The curve drop off will increase rapidly and non-linearly once the discharge rate goes above 2-3C.