Forum Discussion

Nomad II

Jul 24, 2017

Battery isolator?

I've had three isolators fail - two replaced via warranty - but again, a fail. So, I had to bypass it to get Lance Truck Camper battery charging on the road to get ourselves home last trip.

Now, when I shut the battery disconnect, it shuts down battery power to the camper, but if I leave the connector wire to the truck, it draws power from the truck battery. SO, I can't leave it, obviously.

ANyone recommend a good quality isolator that will stop the truck battery drain while camping, but just allow charging on the road. I'd prefer not to install a disconnect switch, which is practical, but then manual, which it OK with me anyway.

What benefit does the isolator actually give us, when installed? Other than separating the two batteries from the charge drain??? Thx M44

12 Replies

MEXICOWANDERER
Explorer
Jul 24, 2017

https://www.allbatterysalesandservice.com/browse.cfm/4,5736.html

Only a tiny negative ground wire is needed. No switches. Automatic on and off. Bulletproof. And maybe 500% stronger than the garbage grade metal can relay/solenoids. Install it and forget it.
KD4UPL
Explorer II
Jul 24, 2017
What are you using? I've had very good luck with Blue Sea Automatic Charge Relay (ACR). It's a voltage controlled switch that combines that batteries when the voltage rises (like when the engine is running). When the voltage drops below the set point it separates the batteries. I've got 2 of them wired up on 2 different trucks. I haven't had any failures in about 6 years since I installed them.
Typically an "isolator" was the old diode based device that caused a .7 volt drop across it's terminals. This worked but really cut down on how much you could charge the batteries unless your alternator had external voltage sensing wires you could connect directly to the batteries. As far as I know the diode based isolator has pretty much disappeared from modern day installations in favor of an ACR.