Two Batteries

[firebuild]

Get ready, because here comes a really dumb question.

My bus has two batteries under the hood. How is the workload distributed between these two batteries? Does each have certain task the other doesn't? Does one just provide backup in case the other fails? Are they both charging and operating all the time?

I warned you.

[cycle61]

They're almost certainly wired in parallel, which means the two positive leads are connected together. They effectively act as one large battery. Same voltage output, double the current output. They are both charging and operating at all times. They are not separated to service different loads. They'll charge and discharge together. If one fails, it will take the other one down with it.

[brokedown]

Consider it one big 12v battery that comes in 2 pieces. If you change one, change them both. Since its an E350 it is likely a Group 31 or similar battery which is relatively cheap to replace.

[Rovobay]

They work as one. it takes a lot of juice to turn the engine over when starting. my Chevy diesel pickup also has 2 batteries, one on each side of the engine compartment, but they are connected together.

[2martins]

Originally Posted by cycle61

They're almost certainly wired in parallel, which means the two positive leads are connected together. They effectively act as one large battery. Same voltage output, double the current output. They are both charging and operating at all times. They are not separated to service different loads. They'll charge and discharge together. If one fails, it will take the other one down with it.

You can verify this by looking at how the wires go between the two batteries. Then search for batteries wired in parallel and batteries wired in series and you can compare how they look. I only have one big group 8D battery or I would have been wondering the same thing.

[firebuild]

Glad to know I can learn as I go with some support from y'all.