How to charge an RV battery with a generator

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Running your RV’s appliances on a battery is a great method for many RVers out there. It gives you the freedom to travel wherever you want without worrying about finding hookups to power your rig. However, a situation where you run out of battery with no way to charge it can put a damper on any trip.

This guide will help you avoid that situation. We’ll teach you how to charge an RV battery with a generator so you can cruise through your journey without worry!

Knowing the type of battery you have

RV batteries come in many different shapes, sizes, and types, meaning that not all batteries operate in the exact same way. It’s vital that you know what kind of RV battery you have before you start charging it with a generator, because different batteries have different requirements. The main battery types you need to be aware of are 12-volt and 6-volt batteries, and whether or not your RV battery is deep cycle. These are important metrics because they directly affect how long the batteries will need to be charged for. 


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Safety first!

Dealing with RV batteries can be dangerous if you don’t take the proper precautions, so it’s important that you inspect your batteries before you start charging them to make sure everything looks good. 

Before you even start this process, wear safety goggles and gloves to protect your skin. You might notice that parts of the batteries look corroded, have a sort of fuzz on them, or otherwise just don’t look quite right. If this is the case, use a wire brush and carefully clean the batteries. You don’t want to plug your damaged battery into a charger and risk electrical shock. 

Carefully check over all of the wiring and ensure that nothing is frayed or damaged there. For lead-acid deep cycle batteries, you’ll also want to stay on top of keeping the fluid levels where they need to be. There should be a mark that indicates the proper fill level, and if the fluids aren’t reaching that, top them off with distilled water.

Something to keep in mind about charging RV batteries is that you should never allow them to fully discharge. This will keep the battery healthy and lengthen the lifespan. A great rule of thumb here is to always keep the charge above 20% so that the battery doesn’t have to dip into its deep resources to stay powered. 


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Charging your RV battery with a generator

You’ll need a few items before we get started charging your RV battery. First: a generator.

It’s worth noting that some larger Class A RVs do have their own internal generator, but it isn’t typically designed to charge batteries. While it’s possible to do so, it’s a slow, cumbersome process that won’t really charge the battery the way you want it to. You’ll likely have to shut off the RV completely, including all of its appliances, before you plug the generator’s converter into the batteries you wish to charge. Even then, after taking a few hours to charge up, your batteries won’t have a full charge. They’ll probably just have enough to help you get through a short period of time before you can give them a real charge.

We recommend a portable generator. Keep in mind that you’ll also need a battery charger. 

For your battery charger, you have some options. There are chargers that produce a 10-amp trickle charge that’ll certainly get the job done, albeit somewhat slowly. If charging speed is your priority, you’ll want to shoot for a triple stage charger. These can charge at much faster rates. 

The size of your generator will affect the charger you should get too since more powerful chargers require more powerful generators. For a 10-amp charger, you only need about 600 watts from your generator, but for a triple stage, you’re looking at more like a 2000-watt generator. After you’ve acquired your corresponding generator and charger, you’re ready to get charging!

1. Running the generator

Before you plug everything in, your generator should be warm enough to work properly. Place the generator on even ground close to your RV (a few feet is fine) and turn it on so it can start warming up. Let it run for several minutes.

2. Connect the battery charger to the battery

Next, you should take the battery charger’s black and red clips and connect them to their corresponding terminals on the battery. The charger’s red clip will connect to the positive terminal (indicated by a +) and should be hooked up first. The black clip will then connect to the negative terminal (indicated by a -). It’s vital that you don’t mix these up, as it could lead to electrical shock, which can damage the battery or even hurt you.


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3. Connect the charger to the generator

Now that the charger is properly hooked up to the battery, you must attach the charger to the generator. All this takes is plugging the charger into the outlet on the generator. It’s a good idea to take a look at any instructions that came with the battery charger so that you know what proper charging should look like. Are any lights supposed to come on? What will it look like when charging is finished? Make sure this information matches up to what you see on the charger, and you can charge away!

Finishing up

When the battery has finished charging, it’s time to turn off the charger. Detach the charger from the generator and start unplugging the cables from the battery terminals. You must take them off the opposite way you originally attached them, so remove the black clip from the negative terminal first and the red clip from the positive terminal second. 

After finishing that, you’re all done! You should have a fully charged RV battery to use to power your rig.

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