Solar power is the eco-friendly solution to keeping an RV battery full so that you can enjoy camping anytime and anywhere.
Figuring out how much power your RV requires to fully function off-grid makes it difficult to know how many panels and batteries you need.
To simplify the task of how much solar power you need for your RV, follow this guide where I explain:
- Why solar power is a good option
- How to calculate the solar power your RV requires
- RV solar power system components and how they work
- Differences between Monocrystalline vs. Polycrystalline panels
- Answers to FAQ about RV solar
Having solar power on your recreational vehicle opens the door to more camping freedom, so let’s check out everything you need to know!
Why Going Solar Is Smart for Recreational Vehicles
Solar Provides Flexible Power and Camping Options
The best reason to install a solar power system on your travel trailer or motorhome is for more camping flexibility.
Many of the most beautiful and relaxing campsites don’t offer electrical hookups, making dry camping difficult.
Having a solar panel array charging up your RV’s house batteries will provide the power you require when camping off-grid.
A smaller system is ideal for low-wattage draws like RV lights or the coffee maker for weekend boondocking trips.
A large system can generate enough watts for running large appliances like the refrigerator or camping off-grid for weeks.
RVs With Solar Power Help the Environment
Using solar is eco-friendly by only requiring sunlight to operate, which reduces your overall camping impact on the environment.
Solar power is quiet. Noisy generators keep your lights and appliances working but quickly ruin the peace of camping.
Going Solar Can Save You Money
It’s a standard practice for campgrounds to charge monthly guests a bill for electrical use. Having solar can offset or eliminate this charge.
Another useful aspect of solar is the low maintenance that only requires wiping down the panels every few months to remove dirt and check that the wiring is secure.
How to Calculate RV Solar Power Needs and Cost
Before buying a solar power system, you need to understand the watts and amps your RV lights and appliances use and how many amp-hours you’ll require of your battery bank to keep them running.
Start by using an RV solar power need calculator to figure out the power you need your RV solar system to generate over a day.
A light may draw 1 amp, which means it uses 1 amp each hour it’s lit. If it’s on for four hours, you’ll need four amps of power from your RV battery just for that single light.
For simplicity, the average daily amount one 100-watt solar panel produces is around 30 amp hours given five to eight hours of sunlight exposure under perfect conditions.
The problem is that not every day is sunny, nor do all panels gain full tilt to capture every last bit of solar rays.
To offset diminishing solar panel efficiency due to angle or weather conditions, you’ll need to add a 20%-25% buffer over your base power needs to stay in full battery charge.
The real culprit in calculating your solar power needs is that you can’t drain down lead-acid camper batteries by more than 50%. So if the battery rates for 100 amp-hours, you can only use 50 at most.
Down below, you’ll learn more about RV battery types that work well with solar power setups and how battery ratings affect amp-hour usage.
How Many Solar Panels Do I Need?
If your RV comes with one 12-volt 100 amp-hour battery, the reality is you’ll need about 300 watts of solar panels to charge it.
For two 12-volt batteries with 250 amp hours, expect to need 600 watts of solar panels.
A four-pack battery bank with 400-600 amp hours will require at least 1,200 watts of panels, and for those who want extreme amounts of amp-hours, a bank with eight batteries with 960 amp-hours, you’ll need 2,000 watts of panels.
You may wish to know how long it takes for a 100-watt solar panel to charge a battery so you can better understand what your RV requires.
The answer can be 10 hours to nearly a week depending on battery amp-hours, sun conditions, and parasitic draws off the system from charge controllers and other components.
Average Costs of RV Solar Kits
An RV solar kit will consist of only the solar panels and usually a charge controller, but no batteries, monitors, inverters, or installation costs.
For the kit alone, expect to pay on average:
The total cost of extras will range between $500-$1,150 before professional installation.
RV RV Solar Power System Components and How They Work
Here are the components you need to safely install a solar power system on your RV:
- Solar panels
- Charge controller
- Battery monitor
RV Solar Panels
RV solar panels can be rigid or flexible and come in different sizes so you can tailor fit them to your recreational vehicle.
The panel’s components create an electric current as sunlight hits the array, and a wiring harness delivers the current to the charge controller.
Flexible vs. Flat or Rigid Panels – Which Is Better for RVs?
Flexible Solar Panels
The advantage of flexible solar panels is they are lightweight and attach directly to your RV roof, so they look cleaner and less bulky than rigid solar panels.
On the downside, flexible panels glue to the roof, making removal at a later date difficult without damaging your roof’s membrane.
Many manufacturers state walking on the panels are safe, but doing so creates tiny fractures in the cells reducing their power output and life-expectancy.
Flat or Rigid Solar Panels
Non-flexible solar panels are known as flat or rigid. The panels have a glass surface set within an aluminum frame.
Rigid solar panels are more durable, so they work longer, even under harsh road travel and weather exposure.
Panels sit a few inches above the RV’s roof, allowing airflow to reduce heat buildup. You can tilt the panels out of the way to avoid stepping on them during roof maintenance.
On the downside, rigid panels weigh more, are difficult to mount between RV roof structures like the AC and vents, and look less attractive.
RV Battery Bank
RV batteries should be deep cycle, which provides power for both high-draw appliance starts along with stable running power.
RV battery banks may comprise of a single unit or two (very common for average size campers) up to six or even eight on large motorcoaches, fifth-wheels, and toy haulers.
Batteries have different amp-hours and ratings so reading the labels is very important to find the right ones for your solar power system.
Battery type can be lead-acid, lithium, or AGM (Absorbant Glass Mat). Lead-acid batteries need to remain above 50% power to stay in good working order.
Lithium batteries can discharge to a much lower number (down to 5%-10%) without damage so that you can run camper appliances longer on a single charge.
Lithium batteries also weigh less, are sealed and don’t need water, and have no off-gassing to avoid worry about where you place them in your camper.
AGM batteries are a step above lead-acid as the material inside, often called a gel, holds the electrolyte solution inside the battery against the plates for a consistent level of charging. AGM batteries are sealed, which avoids any hassle of watching water levels in the cells.
RV Solar Power Charge Controller
A solar charge controller is simply to regulate the amount of power entering the battery from the panels.
Too much power can overcharge and overheat the battery, and ruin lifespan.
PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking) are the two types of controllers most common for RV solar power systems. If you can afford it, always go with the MPPT type, as they do a more efficient job controlling all aspects of power transfer.
Can You Overcharge a Battery With a Solar Panel?
Without a solar power charge controller, you can easily overcharge a battery as there will be no way to stop the current running to your battery from the panels.
Another common question is, “Can you hook solar panels directly to a battery?”
Again, you can charge up a 12-volt battery via direct wiring from a solar panel, but you could easily ruin the battery by overcharging and boiling the contents without constant monitoring.
RV Battery Bank Power Inverter
An inverter is a unit that transfers DC electrical power from the battery bank to AC electrical power so you can use your RV’s outlets and appliances.
Not all inverters are created equal. Expect models that can handle 2,000-3,000 watts to be bulky and heavy, often in the 50-pound range.
You’ll need to match your inverter to your solar power setup’s overall size and wattage requirements.
Some inverters work as a battery charger once you plug your camper into shore power, but the unit will need 12-volt power to kick on this feature.
If your battery bank is low on charge, it may not come on when you plug into a power pedestal. This issue will lead to you waiting for the sun to charge up the battery enough to start the inverter charging feature, which can be a bit frustrating when you want to use shore power for faster charging.
Pure Sine vs. Modified Sine Inverter – What’s the Difference?
A pure sine inverter sends a clean and consistent sine wave through the wiring, which is best when you plan to plug in electronics that are sensitive such as computers.
Many appliances will work better and last longer on pure-sine technology.
Modified sine converters cost less and are fine if you only need the power to run basic camper features like the water pump.
RV Battery Bank Power Monitor
A battery bank power monitor isn’t a requirement for a recreational vehicle solar power system, but it sure is worth the money to install one.
Even without a solar panel array, using a power monitor for the battery is an excellent way to see at a glance the health of your camper’s battery.
A battery monitor has a display that clearly shows the power left in your battery bank. No need to pull out volt-meters or otherwise manually check your battery to figure out your power usage.
Modern versions connect the monitor to your phone via an app, so you can keep track of your RVs battery power anywhere, even when you put it in storage.
Polycrystalline vs. Monocrystalline vs. Amorphous Solar Panels
Here are the three different types of solar panels to choose from when setting up your RV:
Mono-Crystalline solar panels have a single crystal with super thin silicon crystal individual cells. These panels generate more power, even under poor lighting conditions, but they do cost the most.
Poly-Crystalline solar panels utilize a group of small crystals to capture energy from the sun. These solar panels are a bit less efficient than mono-crystalline panels but are much more affordable, making them the top seller for RV solar installations.
Amorphous solar panels are thin and feature silicon cells on a backing material. These panels are the cheapest to purchase and are highly efficient but require more space than the mono- and poly-crystalline panels.
The Difference Between Solar Panels, Monocrystalline/Polycrystalline/Thin Film, off-Grid RV Living
Solar Panel Efficiency
Panel efficiency is directly related to the angle of your solar panel array along with weather conditions such as clouds.
Ratings on solar panels for efficiency are always for perfect conditions, which you’ll rarely encounter in real life.
You’ll have restraints on how you park your RV in most campsites, which may alter the effectiveness of your solar panels gaining full sunlight exposure.
Polycrystalline solar panels generate a 14%-16% conversion rate of sun energy to electricity, Amorphous delivers 10%-13%, while monocrystalline panels manage a higher 22% efficiency.
Final Thoughts on RV Solar
Solar power systems for RVs require planning to figure out your exact power needs and which type of panels and components will work best to deliver clean energy to your camper’s appliances.
I hope this article explains solar power systems clearly, so you can determine how much solar power you need for your RV.
Solar power on your camper is a significant investment, but the real payoff is having the freedom to camp off-grid whenever you like, no matter how far from civilization you roam!
RV Solar Power FAQs
My RV Is “Solar Ready” What Does That Mean?
Many new-model recreational vehicles come pre-wired for solar panel installation.
Solar-ready means the manufacturer has run wiring harnesses from the roof to the battery compartment to avoid drilling holes in your RV if you want to add solar panels.
Many RV dealers sell solar-ready kits made to plug right into the pre-wired system.
The downside to this setup is that it’s for charging the existing (and most likely single) RV battery. For more power, you’ll need to upgrade the number of batteries and panels on your RV.
Can Solar Panels Power an RV Air Conditioner or Microwave?
Yes, solar power systems can be large enough to power air conditioners or microwaves for short spans but don’t expect more than a few hours of use before batteries drain down.
To run an AC all the time, you’ll need lots of solar panels, a huge battery bank, and a large and extremely heavy inverter, which is impractical for most average RVers.