Battery solenoid

[JetBoater]

Can anyone advise the best or most convenient location to tap into 12v ignition source for a battery solenoid?

My 120 amp battery isolator failed... so now I want to wire in a cheap solenoid, which is what I should have done in the first place. I want to isolate my camper power from the truck batteries.

Thanks !

[rustyk]

I can't give you a specific part number, but my motorhome has a solenoid to charge whichever battery is lower. Sadly, that type of solenoid doesn't come cheap, but it's better than the diode isolator, which drops voltage 1-1.5v.

If you're thinking of replacing the isolator with a solenoid, then IMHO, you're best off getting one made for the task. The risk of another type is that, if the alternator output is interrupted, the alternator diodes could die...

The solenoid I have is similar to the ones on boats - either the alternator excitation is interrupted, or like mine, the batteries are momentarily paralleled during the switchover.