How to Hook Up Solar Panels to RV Batteries

Many people use solar panels to power their RV. By connecting solar panels to your RV batteries, you can enjoy electricity anywhere you go.

Keep reading to find out everything you need to know about RV solar panels and how they work – including how to hook up solar panels to RV batteries.

What You Need

RV solar systems are more popular than ever. Some people use RV solar systems to go off-the-grid, camping in remote locations without sacrificing electricity. Others use RV solar systems to enjoy electricity at non-powered campsites. Some use solar panels to be eco-friendly. 

Whatever your motivation is, you need some basic components of an RV solar power system, including: 

Solar Panels: Solar panels capture energy from the sun in the form of photons, converting those photons into electricity. A solar panel consists of an array of cells. These cells collect energy from the sun and convert it into electricity. Depending on the size of your RV and your average electricity consumption, you may need a small or large array of solar panels.

Battery: You need a place to store the electricity produced by your RV solar panels. Your battery stores electricity, allowing you to use electricity even at night when the sun is down. You have three options for your RV solar panel system, including AGM lead acid, flooded cell lead acid, and LifePO lithium. Most RV solar panel arrays require multiple batteries. To calculate the number of batteries you require, calculate the wattage of all appliances in your house, how long you use those appliances, and how many days you’ll be away from electricity.  

Charge Controller: Charge controllers regulate the amount of electricity your panels produce. Without a charge controller, your panels collect too much energy, shortening their lifespan. A charge controller regulates the voltage and current going to the battery, ensuring your system stays safe and operational.

Inverter: The inverter converts your newly-generated electricity into a form your RV can use. Specifically, it changes the 12-volt DC power coming from your battery into 120-volt AC power usable in your RV. You don’t technically need an inverter for an RV solar panel array. Certain RV appliances use 12-volt DC power, including your lights, water pump, fan, and furnace. However, if you want to use a solar panel to power every other appliance and outlet in your RV, then you’ll need an inverter.

Transfer Switch: Your RV’s electrical system can only handle a single source of power at once. To switch between sources of power, you need a transfer switch. Some inverters come with a transfer switch, while others do not and must be purchased separately.

How to Connect Solar Panels to RV Batteries

As Do It Yourself RV explains, connecting solar panels to RV batteries requires knowledge of RV electrical systems. Different RV models have different configurations. If you’re not confident working with your RV’s electrical system, then consider hiring someone who is. 

Here’s the step-by-step guide:

  1. Mount the solar panels on the roof of your RV.
  2. Mount the charge controller inside the RV, placing it as close to your batteries as possible.
  3. Run wiring from your solar panels to the charge controller. It’s best to run wiring through a refrigerator event or plumbing holes to avoid making unnecessary holes in your RV. Alternatively, you can drill a hole through the roof, then plug and caulk it.
  4. Install a fuse or circuit breaker on the wires between the solar panels and the charge controller. The fuse needs to be slightly larger than the charge controller’s rated current. In the event of a fault, the fuse protects your electrical system and prevents damage.
  5. Connect your charge controller wires to your battery bank (or your inverter). Some solar panels or inverters require you to wire the solar panel first before connecting to the battery bank or inverter, so check the manufacturer’s instructions to verify the correct order.
  6. Install your inverter while following the manufacturer’s instructions. The inverter needs to be in a place away from heat, corrosive battery gases, and other things that could damage it. 
  7. Connect the inverter to the battery, connecting the negative post first.
  8. Double-check all wiring to ensure polarity (positive and negative) is correct throughout the system. This step is crucial before activating your solar panels for the first time. 
  9. Your system is now fully installed except for one final component: connect the RV solar panels to the charge controller to turn them on. You may want to cover the solar panels with a tarp or do this step at night to avoid sparks. 

Other Things to Know When Hooking Up Solar Panels to RV Batteries

Connecting solar panels to RV batteries can be complicated. Here are some tips to make the process easier.

Consider a Battery Maintainer: RV battery maintainers work similarly to vehicle battery maintainers. It’s an AC-fed battery trickle charger. The battery maintainer connects to shore power when available, then slow-charges the battery at night or when your solar panels aren’t generating sufficient electricity. This can avoid a dead battery.

Consider Quick Disconnect Switches for Safety: A quick disconnect switch lets you isolate the RV solar panels in an emergency. 

Use a Combiner Box for Multiple Solar Panels: A combiner box lets you combine electricity from multiple solar panels while also providing the protection of a fuse or circuit breaker. 

Most RVs Work with 200W to 400W Arrays: A standard RV needs a 200 to 400-watt solar panel setup to charge batteries, assuming you have access to direct sunlight. A 200-watt system can power lights, the furnace, phone chargers, fans, and small appliances. A 400-watt system, meanwhile, is ideal for those using the microwave, TV, and other components. 

Buy an All-in-One RV Solar Kit: Instead of buying individual components listed above, you can buy an all-in-one RV solar system kit, which includes everything you need to get started. The kit includes solar panels, a solar charge controller, an adaptor kit, and tray cable, among other components. You get everything you need except the RV battery and optional inverter.

Choose Roof Mounted or Manual Setup: Some RV owners mount solar panels on their roof as part of a permanent array. Others setup solar panels manually, placing them outside in direct sunlight and plugging them in whenever they want to use them. Depending on how you use your RV, one or the other option may be the right choice for you.

Final Word

Solar electricity is more popular among RV owners than ever. Today, many RV owners are installing solar panels to their RVs to generate electricity wherever they go.

By following the steps above, you can easily hook up solar panels to RV batteries, allowing you to power your RV entirely with sunlight.

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