One of the things we have learned is that when doing the parking lot camping, we were running the generator to keep the batteries charged and to run the AC. The plan in the future is to reduce the AC need by either moving North or gain more altitude when it is so hot we need AC. As for keeping the batteries charged, we have some major electrical draws like the refrigerator that will such down the batteries in a day. So I have been researching solar to add energy into my battery bank without the need to run the generator.
Basic diagram of how everything should fit together:
First I will need to add solar panels to the roof of the RV, this is a 100w panel that is one of the smaller sizes in footprint, about 21 inches wide and 41 inches long. I have a lot of stuff on the roof and it is going to be tight:
Here is the what an RV install would look like:
I then will need a charge controller to take the incoming power from the panels and convert it to the 12v that the Battery Bank is (panels put out about 20v and if you put some in series you could have 40v coming from the panels) . The Solar Controller will convert in the incoming voltage to match the battery bank.
Along with some of the attachment equipment, this will wire the solar controller into the battery bank.
I will also need a Battery Monitor to be able to see the amount of current is flowing into the battery and out of it when it is being used to determine the state of battery charge.
The other neat thing is you can get a connector to the solar controller to send information to a bluetooth connected device:
Here are some screenshots of the application on an iPhone
So I hope to fit 12 solar panels on the roof, giving me about 1200w total power which per the web site for the solar panels should “On average, you will be getting about 75% to 80% of the power you pay for. Know that the 100 watt solar panel you are about to buy will only give you about 75 to 80 watts of power during peak sun hours on an average day.”
Now according to the manufacturer, I should be able to expect: “A 100 watt panel produces an average of about 6 amps per peak sun hour, or about 30 amp-hours per day.” so with 12 100w panels I should see 72A max and get a total of 360 AH in a day out of the 12 solar panels. With the existing battery bank I have, I should have about 450AH of usable energy when the battery is full and I see about 25A being used when running the RV on batteries. If I start with a fully charged battery 450AH/25A would give me about 18 Hours of use before I would need to run the Generator to recharge the batteries. With solar, if I get about 360 AH into the battery during the day I should start the night with a fully charged battery, in the 12 hours at night, that should use at most 300AH, and it would be less if I turn off stuff during the night. So in the middle of the day during peak solar production, when I an using stuff, the solar is meeting my needs of 25A and that would leave 52A max to go into the battery bank. Early morning I will be lucky if the panels provide enough power to just meet my needs and as the sun rises, more current above my needs would allow me to refill the battery bank. I can also use the Generator as needed to ensure I start the night with a fully charged battery.
The panels can be tilted in the winter if needed to increase efficiency, but that is a manual process so I am not sure I want or will need to do that. By closely monitoring use, figuring what draws the power (I know the residential refrigerator will be a large draw, most likely 1/2 of the use and with electronics being another one, I can can shut things off at night to minimize the draw off the batteries)
So that is the plan for my solar install, which will be installed in Texas right around Christmas (yep, that is our present to each other) and I’ll follow up with a post later on.
The company I am using is AM Solar at: www.amsolar.com which has a great web site full of useful information. I am meeting one of their solar installers who travel in an RV and does installs on the road. Greg who can be reached at www.rvsolarsolutions.com. I will post again once we have time to run disconnected at some times to do testing of the loads and different methods I can use like turning off the refer at night, turning off electronics and such.
As a side note, we are now just about two weeks away of throwing off lines and getting underway!