RVing can be a life-changing adventure, but not if your batteries go dead. When getting started RVing, many people don’t realize that part of the RV’s electrical system relies on 12 volt power, which comes from your RV’s battery system. The batteries that power the house portion of the RV (ie not the vehicle portion) are called the “house batteries” and in this guide we’ll tell you how to charge RV batteries properly.
4 Ways to Charge RV Batteries
There are a few ways to keep your motorhome or trailer’s batteries charged. We’ll discuss each of them below.
1. Plug into shore power
The primary way most RVers will keep their batteries charged is by plugging into shore power. When your RV is plugged in, your Converter/Charger is typically charging your house batteries at an appropriate rate. Some RVs have a hybrid inverter/charger which is also an inverter.
Most Popular: Victron Multiplus Inverter/Charger
Modern converters like the ones from Progressive Dynamics can detect the state of your batteries and automatically enter different charging modes with different voltages depending on your battery’s state of charge.
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Lithium batteries will require changing your converter to one that is optimized for lithium battery voltages.
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2. Charge with a generator
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The next most common way to keep your RV batteries charged is by charging them with a generator.
Many motorhomes will come with a generator already installed and hard-wired into the RV’s electrical system, so all you have to do is start the generator, and charging will begin.
Many travel trailer and van owners will buy a portable generator.
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To charge your RV batteries with a portable generator, you’ll simply turn the generator on, and plug in your shore power cord to the generator. In some cases, you may need a 30 amp to 15 amp adapter to be able to plug your shore power cord into the generator.
Once you’re plugged in, your hardwired converter/charger in your RV’s electrical system should take over.
If your RV doesn’t have a converter/charger or it’s out of commission, you can plug an external battery charger into the generator, and then clip the battery charger’s wires to the batteries. This is only a temporary solution.
3. Stay charged with an RV solar system
An RV solar system consists of the solar panels, the charge controller, and the batteries. They all connect in sequence to fill your batteries whenever the sun is up.
If you’re going to be off-grid camping a lot, the best batteries for boondocking are lithium batteries. This is because they have a greater capacity for their weight, can handle heavier loads more efficiently, and you’ll have more usable amp hours for the amount of space the batteries take up.
4. Charging RV batteries while driving (alternator charging)
Many RV house batteries are installed so that they’re charged while driving. This is the case in travel trailers, too. By hooking up the trailer’s connection to your towing vehicle, you’ll also charge your house batteries.
You can also use a DC-to-DC charger to charge one set of batteries from another (vehicle to camper or chassis to house in a motorhome).
Top Pick DC-to DC Charger
Questions about Charging RV Batteries
What’s the difference between the RV house and vehicle batteries?
The battery for your engine is a separate battery that is simply to start and power the vehicle portion of your motorhome. If you have a travel trailer, this is the equivalent of your car’s battery under its hood.
The battery for the RV house is what powers the lights, water pump, vent fans, and everything else 12 volt in your RV.
What are the dangers of undercharging your RV batteries?
Consistently draining or under-charging lead-acid batteries will shorten their life and cause them to become sulfated. Keep your batteries charged and hydrated to prolong their life.
One of the biggest advantages of Lithium RV batteries is that you can discharge them down to zero and not damage them. If you do this repeatedly, you will lessen the lifespan of the cells, but we are still talking usually a 5+ year lifespan if you charge and deplete them daily from 100% to 0%, which most of us will never do anyways.
How do I maintain the RV’s house batteries?
It depends on what kind of batteries you have. If you have lead-acid batteries, you need to be careful about discharging them too far, careful about causing sulfation, and keep them filled with water as they offgas when charging. Every once in a while you may need to de-sulfate and equalize them.
Other batteries like AGM and lithium batteries are maintenance free.
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