24 volt battery isolator switch

[trailertam]

If i have a vehicle with 2 x 12 volt batteries wired in series to give 24 volts, and i wish to install a battery isolator switch, does it matter where it is installed. Either the negative battery lead, the positive battery lead, or the lead joining the + to the - between the two batteries.

Thanks

[Buenchico]

If the negative terminal is connected to the chassis, current can bypass a switch in the negative lead (through the chassis). That's why the switches (in all modern vehicles) for the ignition, lights, wipers, radio, etc are always in the positive power lead. So I'd recommend also putting your switch on the positive lead.

[Hymie]

It will make no difference which of the three locations you choose – all will isolate the battery.

Given that most modern vehicles need a constant supply for the alarm/radio code/ecu etc. disconnecting the battery might have (as yet) unforeseen effects.

[trailertam]

one of the batteries has no electrolite in it. Is it possible to refill the battery and have it working propoerly again or is dead as a dodo
Thanks

[Hymie]

Well, you’ve nothing to loose but the cost of the electrolyte – give it a try, but I would not be too hopeful.