Dual battery system Ford E350

Howdy all,
I have a 2006 Ford E350 van originally used as a paratransport equipped with an electric hydraulic wheelchair lift. The van is outfitted with a dual battery system, which is new to me. The van wouldn’t start yesterday and wouldn’t take a jump. When I hooked my battery charger up to it, my charger told me the battery had sulfated. Pulled the starting battery out to charge and now it is charging just fine. So I’m suspicious of the accessory battery. To wit, I have a couple of questions:

  1. Is it possible the charger was reading the status of the accessory battery as being sulfated?
  2. How do I isolate the two batteries so they’re not always connected to one another?


Most likely it already has some sort of isolator installed.

Don’t trust a charger saying the batteries are sulfated, and it really doesn’t matter anyway. It will work, or it won’t, simple…


"Always avoid expensive solutions to cheap problems." ~ OffGrid