Battery Cutoff Switch

[ntsqd]

Two batteries. How are they actually connected to each other and the vehicle? If they are connected positive to positive and negative to negative with heavy cables, and then the vehicle's positive vehicle connection is at one battery and the vehicle's negative connection is at the other battery then a battery switch in either vehicle connection will disconnect the batteries from the vehicle.

If that is not how it is wired then pictures are likely going to be needed.

 

[60Works]

My experience has been that every solid state switch leaks current, even the expensive ones. Blue Sea disconnects are the best I've come across. The smaller version is big enough for the 100A starter draw. They can't be remotely activated like solid state but they work without leakage.

 

[ntsqd]

Worth a look: High Voltage Battery Disconnects | Rincon Power - https://www.rinconpower.com/products/battery-disconnects
They are made in Carpenteria, CA, USA. Can find them sold on digikey.
Not true of the battery switches (no idea who makes those), but the high power contactors sold by Blue Sea Systems are made by the company that all of Rincon's main people used to work for before a multi-national gobbled it up.