Installing Small Scale 12 Volt Solar Panels and Adding 110 Volt Power on a Camper or RV

How to add 12 volt solar panels and common 110 volt power to a camper.

I wanted to add some green energy to my camper to increase the amount of time I can spend boondocking, reduce the amount of fuel needed to prepare food, to provide light and to have back up power for my house. I always like to do things as inexpensive as I can so I began looking for used panels. Solar panels don't wear out or break like a generator. They do loose some output over time, but as long as they don't suffer physical damage they will continue to make usable power for many years.

I found three 45 watt 12 volt panels on eBay for about $100. They were from a cell tower that was being updated. They were only about 3 hrs away so I could drive there and save on shipping. I constructed a mounting rack from standard 1/2" npt steel gas pipe available from Lowe's or Home depot. I have a tap and die set that I picked up for a couple bucks at a yard sale so I can make custom length parts. I could have welded a rack from angle iron, but I wanted to use material that would be easy for the average person to duplicate. Gas pipe comes cut and threaded in different lengths, but the full length 10 foot sections are the best price. The store should give you one cut and thread with the purchase of a full length pipe. It can be more time consuming, but you can save quite a bit of money if you cut and thread as many of the connections as you can.

I attached the panels to the gas pipe with 1/2" clamps and self drilling screws. I was able to run the gas pipe through the frame of the panels on the front edge to lower the height. I couldn't do the same on the back side of the panels because the electrical boxes were in the way. This left the back of the panel slightly higher than the front. Hopefully this should put some down pressure on the rack while I'm driving and allow rain to "self clean" dirt and dust from the panels.

My camper has a pop up roof and there's not much support in the roof itself. The strength is around the outside edge. So I cut some flat stock steel to bolt to the edge of the roof and tapped it to thread the gas pipe into it. I used gas pipe flanges and fender washers to mount the four corners of the panels to the roof. The flanges are sealed with flashing cement also known as roof muck. I used several gas unions to allow the panels to be removed from the rack without the need to disturb the flanges and the sealant. The panels could be placed in the sun while the camper is parked in the shade or two unions can be opened to allow the panels to be tilted to access the electrical connections if they need to be serviced.

The panels are wired with a quick connect plug so an extension cord can be added if the panels are removed from the roof. Wiring the panels on a pop top was a bit tricky. I needed to allow for the movement of the roof. I also wanted to minimize the amount roof penetrations. I ran the wire under the edge of the roof along the canvas and into the camper with the wires for the marker lights. The wire runs through a cabinet and to the trace charge controller. The controller regulates the power to prevent damage to the batteries. There are two types of controllers. The inexpensive one works, but it doesn't maximize the power from your panels. A MPPT controller is much more money, but it squeezes out more power. You need to weight the cost verse the output for your needs. You can always start with a standard controller and upgrade later. picking a controller with a higher amp rating will allow you to add more panels later. In my case I can't add more panels because I can already feel the extra strain when I raise the roof. I could carry some inside and deploy them on the ground, but that creates it's own problems with storage and space.

At this time I have two Optima yellow top batteries, but I might upgrade to a pair of 6v golf cart batteries later. I have a 150 amp golf cart fuse on the positive side of the batteries. It protects the inverter cable and the cable that runs along the truck frame from the alternator from causing a fire if the cable shorts out. There is a similar fuse on the other end of the truck cable to protect the truck batteries and alternator. The house ( camper ) batteries attach to the truck with a golf cart plug to allow the house batteries to charge from the truck ( see my other articles for details on setting up the truck wiring ).

My camper gets 110v power from a Xantrex 1000 watt inverter. It was rebuilt unit that I found online for $65. It's mounted inside the camper on the wall that is just on the other side of the battery box to keep the cables as short as possible. It only has two outlets so I added a small power strip right next to it. I found it hard to believe, but I had no 12v power port in the camper. I installed a couple cigarette lighter plugs next to the inverter for 12v accessories.

This article has several photos attached. Please click the icon on the photo to see all of the picks. Use fuses as close to the batteries as possible to protect all of your wiring. Securely clamp all of the wires and use grommets where they pass through walls.

Since my camper spends most of it's time in my driveway it gives me back up power in case of a storm. I can run an extension cord into the house to power my sump pump, run the fridge or other items. It can't power everything at once, but I can pump out the basement, then run the freezer for a few minutes to keep the food from spoiling. If the power failure lasts a couple days and the panels can't keep up, I just start the truck and use the alternator to charge the house batteries.