Engine Battery-Coach Batteries Solar

[Grumpy Grampa]

Ne be question. I am hooking up a solar panel to keep my four six volt batteries charged for the coach . What about the engine battery? I can go by every couple weeks and start the engine, or separate solar system?

Thanks for your input

[DavidEM]

MHs usually have a Precision Circuits BIM 160 or an Intellitec BIRD to manage coach to chassis battery connections. If they are working properly then any charge to the coach battery will be passed on to the chassis battery if it gets a bit low.

I have the BIM 160 on my 2021 Axis and it is a little hard to check as the chassis battery has to drop to 12.5 volts for the connection to be made.

I think I would set it up as you propose, then check the chassis battery voltage after a month in storage.

David

[Grumpy Grampa]

Thanks

[Scubawise]

Check that BIM 160. Mine was drawing power from chassis when coach low. Bim replaced as good will from Thor

[Chateau_Nomad]

Originally Posted by Scubawise

Check that BIM 160. Mine was drawing power from chassis when coach low. Bim replaced as good will from Thor

Ours is a 2020 (2019 Ford E-350 cutaway chassis). Shortly after we bought it new, the dealer contacted us - there was a recall on the Precision Circuits Battery Isolation Manager (BIM-160). It was replaced under warranty.

If you create an account with the Thor Owner's Resource web portal, you can find exactly what is installed in your coach. There is also an explanation of the method it uses to keep both coach AND chassis batteries charged.

[Grumpy Grampa]

Thanks.,I noticed the 160 info says good for solar. It doesn’t mean connect solar cable to this, does it. I thought solar went to positive then negative to ground. Thanks for info.

[Chateau_Nomad]

The solar panels charge your house batteries via a solar charge controller - which regulates the voltage and amperage flowing into the batteries. The chassis battery is connected to this circuit via the BIM. There is a wiring diagram in the Precision Circuits literature.

The BIM is kind of like an electronic switch/controller, whose primary purpose is to prevent the chassis battery from being excessively drained, which would present a "no engine start" situation. It regulates charging of the chassis battery - regardless of where that charge comes from. In the event the chassis battery is drained, the BIM also allows connecting to the house batteries (using the emergency start switch) to start the coach engine.