RXV HV/LV BMS Shutdowns

[MrBritGolfFan]

Originally Posted by Sergio

You may need a smaller load for P1 if your normal voltage ranges are that low.

The original values I chose were based on a Leaf cell chemistry, it was a compromise between keeping the relay coil cooler by using less voltage across the coil but still allow the relay to click at low pack voltage.

Once closed that relay will hold the contacts until around 5v so no chance of dropping under load.

The guaranteed turn ON voltage is 36v but usually they close with less voltage.

There is also a "fudge" factor on those 12v lights as different manufactures use slight different resistors depending on the brightness they want, and different LED colors provide a larger "constant" voltage drop that affects its interaction with the circuit as the pack voltage drops.


Anyway, the best thing to do is to measure the voltage between:

1. Solenoid Big Post on Controller side to BMS C-
   
2. Measure the voltage between the relay coil terminals (1/4 quick connectors).

Once we know how much effect that 12v light is having in the circuit we can make adjustments.

Thanks Sergio

Checking now. My pack is 35v to 46.8v. Nominal is 42.8v.