20 - Solar Power and Battery Bank

Adam and I used to live on our respective sailboats and we know a little bit about solar power. Winnefred came with a single, marine lead acid deep-cycle battery. Not surprisingly, it was completely dead. The battery compartment in the RV can only hold a single battery. We decided to go with 2 six volt golf cart batteries, wired in series, to create a 12 volt system. This is probably the most bang for the buck. I'm certainly no expert, but this is what we decided on. We mounted the two batteries in the compartment above the former battery compartment. This way we could vent the new batteries to the old compartment and feeding the wires from the old battery was only a matter of a foot or less. Like I said, we're both sailors, and we both have some knowledge about how to build a 12v system on a sailboat. We crimp, we don't use twist on connectors. The near constant motion of a sailboat or of an RV, means that those wires are moving, even if only a little. That little movement can chafe in no time. We've also been using stainless fasteners on everything. Probably a little overkill, maybe but it sure seems like a lot of RV's have water damage and subsequently, rusty screws. If you are considering solar, make sure you get a charge controller. The charge controller will make sure you don't discharge current at night (yes, that can happen) and it will make sure you don't over charge your battery bank. I highly recommend getting an MPPT charge controller. It's not a brand, it's a type of charger. I don't know all of the technical stuff, but I do know that MPPT charge controllers will ensure a longer life for your batteries by adjusting the charge to the state of the batteries. It's complicated and you can research it if you're really interested.

We're very lucky to get hand-me-down solar panels that my parents had on their cruising sailboat. That's right, these panels sailed with them to Ireland, the Med, the Caribbean and back to the Chesapeake Bay. They are 2 X 55W, 3.45amp Siemens panels. They won't handle our air conditioning, but certainly our phones, laptops, tv, stereo and maybe our refrigeration. Our lights are all LED so they barely draw any current at all.

Adam is mounting the brackets onto the backs of the 2 panels

We put the panels along the side of the RV so that they can be accessed easily, by ladder, for adjusting. Solar panels get the most output if they can be adjusted to face the sun directly at a 90 degree angle. They will still output current if they are not angled to the sun though:

Adam ran the wiring from the panels down the exhaust "chimney" for the refrigerator:

Wiring coming out of the positive side of one of the panels:

More wiring, the panels are wired in "series" right now. However, this means that if there is shade on any part of either panel, the current output is diminished significantly. We plan on changing to wiring in "parallel" to eliminate this issue.

Our "new" battery compartment, under the seat of the dinette. The 2 6v batteries are wired in "series" to create a 12v system. The batteries are in proper battery boxes which will be strapped down securely. There is ventilation through the bottom of the compartment.