Hidden coach battery

roycej

New member
Nov 4, 2022
29
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I've started checking the electrical system in my Birchaven RB. There were two batteries under the hood, passenger side. Engine battery and coach battery. Both are 5 years old and will need to be replaced. I plugged into shore power and had no 12 volt inside the coach, so I assume I need a new converter. The shore power cord would only pull out about three feet so I looked inside under the floor of the bathroom wardrobe/closet. The cord was wrapped around a battery box which had another coach battery inside (long dead I'm guessing).

Don't know how long it would have taken me to find this if I hadn't been looking for the rest of the power cord.
 
I have a 26 foot Coachmen upfit Royale RB, and it has three batteries, but the rear battery is in the generator box. I would recommend you make sure that you don't have a lead acid battery in the living space, as they off gas bad stuff. How you want to use the coach will determine what type batterie are best, and the wiring between it all. Your profile says new member, if you want some suggestions on what to look for and some solutions feel free to ask, it can be pretty varied depending on your goals. I think your rear battery is a previous owner (PO) add on for more capacity.
 
Unless that's a LiFePo battery or a very well ventilated area, it's a dangerous situation. A lead acid battery will off gas hydrogen sulfide gas and likely to explode. There was not a battery there when new.
Please give me the VIN if your coach for the GMC Motorhome Registry. www.gmcmhregistry.com
Hi Billy, you already have the VIN in the registry, thanks. The compartment has two vents: one above the generator enclosure which vents behind the generator door, and a precision-cut screened vent out the bottom. The battery was in a plastic box which was certainly not original.
 

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Glad whoever added that took precautions. I see you updated the registry in October. It was once native to Weatherford, TX. I wonder, is it repainted pink and gray?
No, and I'm probably happy about that. It's a pale yellow shade with remnants of gray stripes.
 
That is the original battery placement for the side bath Birchaven. My guess is that they wanted it there to avoid voltage drop while starting the Onan.
Mine is rear bath, but I found an electrical diagram that shows three batteries: "GMC car battery" and "GMC RV battery" up front and "Aux battery" near the generator. I don't know if it was optional or standard, but seems to be a factory setup.