Battery overvoltage protection - dump load

Hello, because i run several times into overvoltage cutoff and have no other brakes than my motors on electric boards, i tried to make a circuit to solve this problem. It should switch a dump load in parallel to my battery and '‘v’'esc whenever the voltage in said lines goes above a set value (0,5 volts less than cutoff is set in vesc), and switch it back off when voltage is aprox. (depends a bit on set voltage) 0.5v lower than the set point. here is my circuit: circuit%20(1) any toughts? how big should the dump load be? the same size as i set my battery regen current? and any ideas what i could use, these resistors are big…


Try figuring out why you are getting this errors first. What is your setup? Is there a specific time/ something you’re doing that makes this overvoltage happen?

it’s normal you brake and generate voltage, when the battery is full it’s full… read again maybe

There is also another easy solution, charge your batteries only to 4.1-4.15V. You may loose 5% usable capacity but you shouldn’t have overvoltage problems anymore. You will also charge up faster since the last couple % charge usually very slowly. Depending on the batteries you also might get a modest amount of extra life cyles from them (for certain if you really over charged them sometimes)

If it’s from full battery and regenerative braking then just try not to charge your battery to full unless it bothers you that much to lose a small amount of range. The only issue might be the balancing if you use BMS, since the balance mode kicks in when battery is full.

no, i rather design a circuit to solve this problem by it’s roots… even if i only charge my 10s (21Ah) pack to 41V i run into this problem sometimes… i’m not stupid how can you even give such advise, do you understand at least the circuit?

Yup, I’m happen to be an electrical engineer. No one implied you’re dumb, just suggested it’s not worth the trouble and time from my aspect but whatever dude. Good luck with that.

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well i doubt that too, but it’s fucking scary to go over 30km/h down a mountain and suddenly brakes skip out

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