As boondocking and Off the Grid camping become more and more popular more campers are turning to use solar as there power source. Having an RV solar controller is practically a requirement for any solar setup after learning about them. So what is a solar controller?
A solar controller or also known as solar charge controllers are used to reformat the power coming from the solar array and feed it out to a battery bank in a way that safely charges the battery without overcharging it. Keeping your entire RV solar system safe from overheating, fires, and malfunctions that could cost a lot of money.
The Types of RV Solar Controllers
There are 2 main types of controllers PWM and MPPT. Both have different price points, technology, features, and suggested uses. While neither are wrong there may be reasons you should lean more towards over the other.
PWM (Pulse Width Modulation)
This is a cheaper option that is suitable for a solar setup of 300W or less. PWM is less expensive, slightly easier to install, and a simpler style than the other controller. It operates by constantly sending a pulsed connection between the solar array and the battery bank. As the battery bank gets charged is reaches a higher voltage and those pulses will shrink in length until it eventually becomes an open circuit as the battery becomes fully charged.
MTTP (Maximum Power Point Tracking)
The more expensive feature-rich option, allowing Bluetooth connection to see how much power you’re generating, using, and charge percent of your battery bank, all in real-time. MTTP basically has like a transformer between the solar array and the battery bank that allows the solar array to operate at one voltage and the battery bank charging portion to operate at another voltage. This type of controller is slightly more efficient than PWM.
Which one should you buy? I personally just stick with the 300W rule. If your solar panel set up is rated for more than 300W go with MTTP if not, stick with PWM for your RV Solar Controller.
Why I chose a Controller before buying any Panels
Some campers seemed confused by the idea of me doing this. The best way I can explain it simply, safety. I have a lot of electronics at home. I try to run everything I can through a surge protector to protect my things from sudden current spikes. While a Solar controller is very different the idea is the same I wouldn’t set up a computer without a surge protector and I wouldn’t set up solar panels without a controller.
Some solar panels can be connected directly to a battery, if you are unsure please check you manually. Some are even plugged and play solar kits you just chain together. If your solar panel can’t be connected directly to a battery you shouldn’t do this. connecting solar panels directly to a battery bank without a charge controller will cause the solar panels to eventually bring the battery bank up to the open-circuit voltage of the solar panel or, ruin the batteries whichever happens first neither is a good outcome.
Starting with an RV Solar Controller is a great place to start when wanting to power your camper by the sun. If you start with the solar controller you can pick the features that are important to you and find something that will work best for you. Then you can buy the solar panels after that. I have met campers who said they wish they got a different solar controller but they bought their panels first and they weren’t compatible with the controller they wanted.
Here are some common suggestions.
15 Amp = 220 Watts
30 Amp = 450 Watts
50 Amp = 680 Watts
70 Amp = 950 Watts
And it keeps going up to 1400 watts, but you most likely won’t get near that when talking about an RV solar controller.
My recommendation
I personally use a Victron Smart 75V 15A for my setup. I like having the ability to see real-time info through my phone about the power. And Victron has the added ability to select what kind of battery you are using with it. Currently, I have AGM or Deep cell batteries the big heavy ones that look like car batteries. In the future, I want to upgrade to lighter longer-lasting Lithium-ion battery packs. The Victron RV solar controller has the ability to choose the battery type is it connected too.
https://www.victronenergy.com/solar-charge-controllers/smartsolar-mppt-75-10-75-15-100-15-100-20
