Quote:
Originally Posted by redpoint5
I've heard that several times on here. I assure you that 290 peak amps isn't unusual. The Camry draws 255A, and the Cummins 5.9L peaks at over 400A, which is higher than my gauge can go. The motorcycle peaks at 80A, and it only has a 0.6L engine.
A motor at dead standstill IS basically shorted to ground.
The battery only has to sustain the ~300 amps for the fraction of a second it takes for the motor to begin spinning. After that, it might fall to 1/4 of that.
There is a reason batteries need to be rated at 400+ CCA. The initial surge is tremendous.
FYI- A stopped motor that has not yet begun to spin IS a locked motor.
|
This is exactly what I was getting at. "Peak" is really a misleading term and actually depends on the resolution of the meter being used. A meter that samples at 1000Hz will record a much higher "Peak" than one that samples at 100Hz. Electronic devices have 5, 10, 20 second etc current ratings.
IMO, these high peak values are for such a short amount of time that small LiFe packs are quite capable of handling them. I have one of those 1/5 scale R/C buggies that I converted to electric power it runs the same LiFe cells as my 1:1 Fiat and draws 'peak' currents of 7500W (measured by the onboard data logger) and this happens dozens of times per charge.
That's over 400A
