Current at 72V on a formally 35A controller

[OpAmp]

A few years ago I modified my originally 35A Crystalyte controller in accordance with Fetchers Crystalyte Controllers - Repair and Modification information thread. The controller now has 12 irfb4110 transistors. At 48Volts I let the cycle annalist pump the 5303 motor with 50 amps.
I now hit the controller with 72 volts and I’m unsure if 50 amps at 72 is a bad idea. The unpredictable PWM Is hard to predict but thankfully you guys can help me, I hope(;
If I blow the controller, I wont be crushed but I would love to see this pig last.

 

[liveforphysics]

If the peak battery current is 50amps, it means the FETs shouldn't be seeing much over 150amps peak for the pair, so it should be fine.

 

[OpAmp]

If the peak battery current is 50amps, it means the FETs shouldn't be seeing much over 150amps peak for the pair, so it should be fine. [/quote
Cool, I was thinking about current spikes and came to the conclusion that the resistance in the wires between the controller and the motor will drop the fearful PWM potential. Ha Ha, I love this stuff.
I programed the CA to only allow 35amps and I got it up to 40mph, when I hit the brakes I couldn't get my mind off how hot those brake pads must be.
I'm going to give it 50 amps tomarrow. If it doesn't like that, I'll be buying a new controller.

 

[The Mighty Volt]

Hi, I have a related question: what is the peak amperage generated by 12AH 72v of A123 26650 cells, and can a 50A 72v rated Crystalyte controller comfortably absorb this amperage?

If too much Amperage is generated, what practical steps can be taken to address the matter?

Many thanks.

 

[OpAmp]

The A123s you speak of are monsters. You must know this if you own them. Your controller should and probably does detect Current from batteries by analyzing the current before it sends power to the motor. The 3 Phase Pulse Width Modulation that the controller creates sends PULSES to the motor, and these pulses pump intense current/power if the circuit permits it.