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How To Hook Up Solar Panels To RV Batteries

Camper van solar roof panels with skylight top view Motorhome - feature image for How To Hook Up Solar Panels To RV Batteries
Here’s how to hook up solar panels to RV batteries so you can stay powered while off-the-grid.

How To Hook Up Solar Panels To RV Batteries

Due to the recent surge in popularity of RV boondocking, RV solar power systems are more popular than ever. If you like to camp off-grid, solar power systems can power your RV with all the electricity you need. Unlike a gas-powered generator, a solar power system quietly charges your batteries by capturing the sun’s energy into electricity.

Simply put, a solar panel works by allowing photons, or particles of light, to knock electrons free from atoms, generating a flow of electricity. Solar panels actually comprise many smaller units called photovoltaic cells.

A solar system requires more than just batteries and solar panels. In order to connect solar panels to batteries to provide electricity, you need to have 5 basic components.

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The 5 basic components of an RV solar power system

1. Solar panels

Solar panels capture photons (tiny particles of light) in the photovoltaic cells that make up the solar panels. Photovoltaic means they convert sunlight into electricity. Many cells linked together make up a solar panel. You’ll need to calculate how many solar panels you’ll need. This can be done through some simple calculations.

2. A charge controller:

Overcharging your batteries will shorten their lifespan or kill them. A charge controller prevents the solar panel from overcharging the battery. It regulates the voltage and current coming from the solar panels going to the battery.

3. An inverter

The inverter changes 12-volt DC power from your battery into 120-volt AC power that you can use to power appliances like your microwave, coffee maker, or TV. You can have a solar power system without an inverter, but it would only allow your 12-volt DC power system to supply appliances like your lights, water pump, fan, and furnace.

4. A transfer switch

The transfer switch is sometimes built into the inverter, but they can be bought separately. A transfer switch automatically switches power going to the RV electrical panel between two incoming sources of AC power. So, power comes from either the inverter or from shore power, but not both at once. Allowing both sources at once would damage the electrical system.

5. The battery

The battery stores electricity produced by the solar panels so you can use it whenever you want. There are 3 types of batteries: AGM Lead Acid, Flooded Cell Lead Acid, and LifePO Lithium. You’ll need to calculate the number of batteries you’ll need by figuring out the wattage of each appliance you’ll be using by how long you’ll be using it for. Then multiply that number by the number of days you’ll be off-grid. Click here for a simple calculator.

Know this before you start

Setting up a solar power system on an RV requires knowledge about how RV electrical systems work and a few tools that you probably already have if you’re reading this. We’re going to discuss the basic procedure on how to hook up solar panels to RV batteries.

It should be noted that each RV model has a different electrical configuration, so although all RV solar power systems need the same components, basic setups may vary. If you aren’t comfortable working with electricity, call your RV dealer or your local certified RV technician.

How To Hook Up Solar Panels To RV Batteries

  1. Mount your solar panels on the roof of your RV.
  2. Mount your charge controller inside the RV as close to your batteries as possible.
  3. Run wiring from the solar panels into the RV to the charge controller. To avoid making unecessary holes in your RV, you could run your wiring through a refrigerator vent or through the holes where the plumbing enters the RV if these are located near your batteries. If not, you’ll have to drill a hole through the roof of your RV to run your wires and thoroughly plug up and caulk any drilled holes.
  4. Install a fuse or circuit breaker on the wires from the solar panels to the charge controller. 
  5. The fuse you install should be a little larger than the charge controller’s rated current. This will help to protect your electrical system in the event of a fault
  6. Connect your charge controller wires to your battery bank (or to your inverter). Manufacturer instructions may say to wire to your solar panel first before connecting to the battery bank or inverter. Always follow the manufacturer’s instructions.
  7. Install your inverter close to your batteries and away from heat, corrosive battery gases, and other damaging elements. Follow the instructions that came with your inverter. Connect the inverter to the battery. Always connect to the negative post first.
  8. At this point, the system is fully installed, but the RV solar panels are not connected to the charge controller. Before making the final connection, it’s important to double-check all wiring to make sure polarity (positive and negative) are all correct.
  9. Now that you’ve checked everything, you can plug in the solar panels into the charge controller. It’s a good idea to do this at night or else cover the solar panels with a blanket or tarp to prevent a spark.

Now you know how to hook up solar panels to RV batteries. For more details, check out this video from All About RVs:

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