How to Charge an RV Battery With a Generator (Step-by-Step)

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Keeping your RV batteries charged is crucial if you want to use your electrical devices when shore power isn’t available.

There are a few ways to charge your batteries in this instance – while driving your vehicle, hooking up solar panels, and the topic of this article, with a generator.

So, let’s learn how to charge an RV battery with a generator step-by-step while simultaneously running appliances like your coffee pot, microwave, and more.

How to Charge an RV Battery With a Generator

To charge an RV battery with a generator, simply plug the RV power cord into the generator like you would a shore power post at a campsite. Your generator should have a standard 30 amp/120-volt receptacle built into it. If it’s 220-volt, then you will need an adapter.

That’s a high-level overview of how to charge an RV battery with a generator. Now, let’s break it down step-by-step and cover some important precautions when using a generator for power.

Let’s use the Honda EU3000IS 3000W 120V Inverter Generator as an example.

Tip: The Honda EU3000IS happens to be one of the 10 best RV generators I highly recommend! Check that guide out for comparisons and in-depth reviews of Honda, Champion, Onan, and other popular RV generators.

It’s important to cover a few safety precautions before we plug in our RV’s power cord and fire up the generator.

Important Safety Precautions

  • Only operate your generator outside and at least 3 feet away from any open windows, vents, or doors.
  • Know how to quickly stop your generator in case of emergency.
  • Read the owner’s manual carefully and understand each of the controls and receptacles, as well as all safety precautions for your model.
  • If using a portable generator, place the unit on firm, level ground.
  • Inspect any cords you plan on plugging into the generator. Replace if damaged.

Once you’ve taken all safety precautions, we are ready to begin charging your RV batteries.

Charging RV Batteries Step-By-Step

Important: Before attempting to start your generator, check the oil and fuel levels and air filter.

  1. Start your generator: Every generator model will be slightly different, but when charging RV batteries with a Honda generator, as we’ll be using in this example, first turn the eco-throttle switch off. Then turn the fuel valve on, pull the choke to the closed position, and turn the key to the “On” position, starting the generator. Finally, push the choke knob back in.
  2. Allow the generator to warm up: After starting your generator, allow it to run for a few minutes before connecting any power cords or appliances to it.
  3. Plugin the RV power cord: Plug the RV power cord into the generator’s built-in 30 amp/120-volt AC plug like you would a shore power post. If your RVs power cord doesn’t fit into the generator’s 30 amp receptacle, you may need a 30 amp twist to 30 amp RV adapter.

That’s it! Your generator should now be recharging your RV batteries, as well as powering any electrical appliances in your vehicle that it can handle.


How Long Do I Need to Run a Generator to Charge RV Batteries?

The length of time it takes to fully charge your RV battery is determined by various factors, including the capacity of your batteries, the output of your generator, the number of appliances you are using, and how many batteries you are charging. If your RV or camper battery has been depleted to 20 – 30% power, it can take up to 8 – 10 hours to fully charge. If your battery is almost full, it might only take a few hours to recharge it to full capacity.

Can You Charge a Deep Cycle Battery With a Generator?

When you are charging your RV’s battery with a generator, you are likely charging a 12v lead-acid deep cycle battery, as that’s what you’ll commonly find in recreational vehicles and travel trailers (though lithium batteries are becoming more popular). So, yes, you can safely charge a deep-cycle 12-volt battery with your generator.

Why Won’t My Generator Charge My RV Battery?

If your generator doesn’t charge your RV battery, it could be for several reasons:

  • Check the battery disconnect to make sure it is not disconnected.
  • Ensure that the converter circuit breaker is on and fuses are good.
  • Ensure that the main breakers on the generator are not tripped.
  • Check the water level and overall condition of the battery.

If you don’t feel comfortable troubleshooting your RV’s electrical system, take it to a certified RV professional for help.

Related: Camper Battery Not Charging When Plugged In?

Does an RV Generator Charge House Batteries?

Yes, your RV generator, when plugged in and running, will charge your house batteries and power any 120-volt appliances.

What Is the Fastest Way to Charge RV Batteries?

Arguably the best and fastest way to charge RV batteries is by connecting to shore power and using a high-amperage multi-stage battery charger.

Related: Does an RV Battery Charge When Plugged Into Shore Power?

Charging an RV battery with your alternator while driving is one of the slower ways to charge it. However, you can speed it up considerably using a DC-to-DC converter. Check out our guide on how to charge an RV battery while driving for more details!

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