Damians github controller

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TheFrankenberry

Re: Damians github controller

Post by TheFrankenberry »

I see that this is a somewhat old thread, but I am building a high-amp controller using these boards. in the $1,000 BMW E36 EV Build 08 : Motor Controller Part 2 video, Damien mentions that the overcurrent limit can be raised with a current sensor change or a resistor change. Well, I would like a much higher high-current cutoff than the 700ish amps mentioned in the video; I'm aiming for something around 1200 or 1300amps cutoff.
My question is, does anyone know quantitatively how to make this change? Say I get a LEM HASS 600-S current sensor and changed resistor R6 on the logic board, how could I know what resistance it should be?

Edit:
Decided I was just being lazy for asking for help without trying. Looked over the circuit closely and even busted out the old circuits textbook. I decided that changing the current sensor and leaving the resistors alone was certainly the most straightforward and easy way to go. I found a cutsheet for the LEM HASS series current sensors: https://www.lem.com/sites/default/files ... _600-s.pdf
The cut sheet shows that the sensor's output voltage is Vout = (2.5V+-004V) +-(0.625*(I/IN)) where I is the current measured and IN is the nominal rating of the sensor. A LEM HASS 300-S experiences Vout = 2.5V+-0.625V at 300amps of course, and Vout = 2.5V+-1.458V at 700amps, the approximate circuit cutoff.
Well a LEM HASS 500-S has a nominal rating of 500A; for it to have the same Vout as the circuit cuttoff, it would be 1.458V = (0.625*(I/500)) => I = 1166A! close enough! With the same output signal as the tried-and-true LEM HASS 300-S, sounds like it should work just fine at the higher current with no other modifications.
For those interested, the LEM HASS 600-S should cut off at 1400A, and the LEM HASS 400-S cut off at 933A.
Please, if anyone with more experience/knowledge sees this and sees a mistake, please correct me!
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