Gab said:
But does low volts cause CA to shut down and reboot ?
At the LOW VOLTS point, it means the CA should have shutdown, saving any last values to EEPROM. WHen power comes back above that, it should reboot. (AFAICR, that's how it's worked for me when I've had power connection issues, cutouts, etc., for whatever reason external to the CA).
It has a throttle plugged in and that does not cut out hence i thought its the cav3?
I don't know about that part--if you mean the throttle continues to operate the controller normally, and the motor still runs, then that means the BMS could not be cutting out.
The voltage could still be sagging below the CA's low volts limit, however, causing it to shutdown even if the controller does not (if it doesnt' sag below the controller's LVC, if ti has one).
If the throttle is wired to the CA throttle input, and controller's throttle comes only from the CA's throttle output, then I don't see how any throttle signal could get to the controller to operate it with the CA shutdown.
Do bms cut out so quick ?
Depends on the BMS and why. SOme have overcurrent *and* under/overvoltage protection, and the current limiting might have a delay, but the under/overvoltage protection probably does not have a delay, as it needs to protect the cells from damage by overdischarge or overcharge.
The thing is i also tried to run the main pack input of a 2nd battery with higher amp cutout and it still did it ?
If you are certain the BMS of the battery is not cutting out, then something else must be causing the voltage to sag so low at the CA that it shuts down.
If you ahve a separate voltmeter, you could hook that up to the battery (or the voltage supply to the CA), and see what the volts reads at the instant the CA cuts out.
Bigger wires to the CA shouldn't make any real difference; it doesn't use enough current to need them.
A larger capacitor might help, if attached right at the CA, but keep in mind the controller usually already has a large capacitance, and is hooked up across the same wires the CA is for power. So if that capacitance isnt' helping, you might need anything from several hundred to a few thousand microfarad (uF), with a voltage rating greater than your battery's full charge voltage.
If necessary, you could add a diode in series with the CA's battery + input, and put the capacitor's + on the CA side of that, and the capacitor's - on the battery - input, and that would prevent the system from discharging the capacitor, only letting it charge it. Then only the CA's load would be able to discharge the capacitor. In fact, you could try just the diode and no capacitor, and it would prevent the CA's internal capacitor from being discharged by the system, and possibly prevent the shutdown.
But I'd try to find out why the battery voltage is sagging so much, first, because it generally indicates some problem somewhere, either at the battery or in the wiring (connections, crimps, etc). The CA issue is likely just a symptom of a real problem somewhere.