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Recreational vehicles use deep cycle batteries. The advantage of these batteries is that they store more power and hold the charge longer than a regular battery. A fully charged deep cycle battery can keep all the devices and onboard facilities running. But when it needs to be powered up, can you use a generator and how to charge RV battery with generator?

Yes, you can use a RV generator, either portable or pre-installed into the vehicle, for this purpose. The ideal time to recharge a battery is before a camping trip, especially if you are planning to dry docking or going to a remote place. You definitely don’t want to end up there with a drained battery.

How to Charge RV Battery with Generator

Even a camper equipped with an alternative energy source like solar or wind power panels needs occasional power boosts. A generator is a perfect option to provide that boost.

A duly charged battery can hold the charge for a long time and power up vehicles, equipment, and appliances. Here is how you can recharge an RV battery through a generator. Don’t skip any step; otherwise, the battery won’t be fully charged.

how to charge RV battery with generator
Recharging RV battery with a generator.

Step 1: Recharge the Generator

The generator has to be fully charged if you want to use it as the power source for the deep-cycle battery.

Check the gas or oil level and fill them up to the ‘full’ level. Check the user manual if you are not sure how to do that. Plug it into an electrical outlet and recharge fully. Before that, start the generator for a while to warm it up.

Step 2: Clean the Battery

Before recharging the battery, you have to clean it because a dirty, damaged battery will be drained even without any use. Don’t forget to switch the vehicle off and put on the emergency brake before starting the cleaning process. Also, remove the battery cables with a wrench. Detach the negative (black) cable before taking out the positive (red) one.

Check the battery from top to bottom to spot any cranks, leak, corrosion, or bulges. There could be dirt build-up on the terminals too. Make a paste of baking soda and water and apply the paste on the dirty terminals with a small brush. Rub until the dirt comes off. Finally, clean with a damp cloth. Use a wire brush in case of removing corrosion.

Wait until the terminals and each cleaned part are completely dry.

Step 3: Prepare the Battery

At this stage of how to charge RV battery with generator, you will prepare the battery so it is ready when you plug it into the generator.

The first step is to look into the electrolyte level. If the fluid level is low, fill it up to the ‘Full’ point with distilled water. The next step is to attach the cables again. This time, attach the red cable before the black one. They should be firmly secured to the terminals.

Then, attach battery charger alligator clips to the terminals. The red clip will go to the positive terminal (featuring a plus sign) and the black clip will go to the negative end (featuring a minus sign).

Step 4: Unplug Other Devices

Unplug other electrical devices so the battery gets the optimum charging. You should also turn off the lights. In other words, there should be nothing that can drain the power of the generator, which should be connected to a 120-V AC outlet.

The charging time depends on a couple of factors. It will be a much slower process with a portable generator than an inbuilt unit. Also, the weather condition matters since the full capacity won’t be achieved unless the temperature is more than 40 degrees.

charging RV battery with generator

Step 5: Plug the Battery

Finally, this is the stage where you will recharge the battery. But before plugging it into the generator, choose the charger carefully. A three-stage charger is the best choice whether the battery is drained, half-charged, or charged.

Now, connect the RV plug to the generator. Two hours are enough for a full charge given that the unit is not depleted. It will be a much longer process if the battery is drained or the charge is below 20%.

This is how to charge RV battery with generator. There is no complicated step except for refilling electrolytes and cleaning the terminals.

Tips and Warnings

Following these tips will help with finishing the recharging smoothly without causing any accident:

  • Charging the battery produces hydrogen gas, which could be dangerous in a congested place. So, do it in a well-ventilated area.
  • Wear protective gloves and goggles because battery acid is caustic.
  • Don’t keep anything flaming or burning nearby the battery or generator.
  • The generator should be in an open or well-ventilated place when running because it produces the deadly carbon monoxide gas.
About Peter Wade

Peter Wade is a co-ordinator and writer at His hobbies are coffee, RV camping and photography. He now enjoys exploring the U.S. by RV with his two dogs. After obtaining a MA degree in Public Relations and Journalism, he had 8 years of experience working for the R&D Department of Outdoorsy. Peter provides a unique look and insightful knowledge about the RV lifestyle, and fills his blog with everything from RV camping guides to reviews about necessary RV accessories. If you are an RV enthusiast and want to get the most-updated trends of the RV industry, Peter’s articles are the must-visit contents.

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