BMS: Avoid damage when charger is wrong connected

[Blackgar]

I am designing a PCB for a low voltage BMS system (<48V).

I try to think ways that could prevent damage on BMS or Charger, when Charger is connected wrongly (Charger+ to Pack- etc.). One solution could be a dedicated connector that do not allow the user to do mistake.

What else could I add to prevent this case? A diode parallel to the output (Pack+, Pack-) may damage the Charger due to high current.

[DavidAlfa]

Two beefy p-ch mosfets and a resistor will do the job.
For 48V, the bidirectional zener is required to protect the gates, they usually can handle ±20V at very most, 12-15V is a safe value.
The voltage drop will be negligible with decent mosfets.

What's the charger open-circuit voltage? If not exceeding 48V in any situation, a 55-60V should be enough, but it's always better to leave a larger margin, 75-80V would be perfect.
The downside of higher voltages is higher Rds, requiring beefier and more expensive parts.

[m3vuv]

seems a silly question for a simple task,just use a standard xt connector,one thing i say is tho is to power on the charger before connecting the battery pack to it,on mine it gives a big flash/arc if i dont.p.s the xt connectors only plug in one way so cant get polarity wrong!.