How To Charge RV Battery With Generator

A 12-volt RV battery is typically used with an RV or a camper van. For on-road travelers, a 12 Volt electric system is convenient to use for power while camping or traveling. Most campers consider their RV battery to be the heart of their Recreational Vehicle, as it provides power for appliances in the RV, such as the freezer or television when connected to shore power. Aside from that, you rely on your deep cycle 12V-battery to fire up the water heater and furnace or to run the water pump.

Therefore, your RV batteries are one of the most important things that should work and have enough power at all times of need. It is highly recommended that before you go outdoors, you fully charge your battery to avoid any problems later on down the road. Of the various charging methods, using a portable or pre-installed, plug-in generator to charge your battery is pretty common these days.

Although charging a battery using a generator is a simple process, it can cause damage to either the generator or the battery if you don’t follow the proper procedure. In this tutorial, you will learn in detail how to charge your RV’s 12 V battery with a generator without much hassle. Apart from that, we would also take a look at maintenance tips and the factors to consider while charging an RV battery with a generator along with others methods to charge your RV Battery.

How to charge a travel trailer or an RV battery with a generator

Even though generators are not specifically designed to charge a 12 Volt Battery, most have the appropriate cables and connectors to do so. They only have a low amperage rating, which means it may take some time.
There are some specific steps you need to follow when charging the RV battery with the generator to make this work safely and correctly.

Step By Step Guide to charge your 12 Volt Deep Cycle RV Battery With A Generator:

  • Step 1: Before using the generator, make sure it is fully charged to its capacity. If not, connect it to a power source. To prevent any unintentional future accidents, apply the parking brake while charging the battery.
  • Step 2: Examine the battery thoroughly to determine whether or not it is free of corrosion. If you find any yellow or white whipped cream-like substance around the end of the cable, put some baking soda on it before pouring water over it. Finally, use a paper towel to scrub the corroded area for 5-8 minutes to remove the rust.
  • Step 3: One thing we have to check if the battery is not a new one, but out of the garage, is the electrolyte level. To do this, first, take off the vent cap by either pulling or twisting. Next, grab a flashlight and take a look at the fluid levels. In most cases, it is recommended to keep the battery fluid level a half-inch above the plates. Furthermore, watch out for overfilling as the battery would start pumping electrolyte out of it in such a scenario.
  • Step 4: Unplug all equipment connected to the power source. This is because we don’t want devices like fans or lights, and appliances like the refrigerator to drain the power your battery needs to charge. If you do this, not only can the generator use all the power to charge the battery, but it can also increase the total time it takes to charge the battery. However, charging time also depends on the weather. If the outside temperature is below 40 degrees, the process may slow down or even fail to charge the battery to its full capabilities. One solution to this problem is to move your RV or the battery and generator to a location with a temperature above 40 degrees.
  • Step 5: Finally at this stage, you can connect the generator and the battery. Connect the RV battery with the generator using the provided RV battery plug. On average, a battery takes 3 to 4 hours to charge completely. However, depending on the condition as well as the current energy of the battery, it may take longer. If the battery only has 25-30% energy left or is in very poor condition, it may well take longer to charge.
  • Step 6: Have an eye out at the charging level of the battery. Numerous Experts have found that overcharging can worsen the condition of a battery. Once charging is complete, make sure to recharge the generator to avoid facing an obstacle on the road in the future.

Maintenance tips for RV Battery

For longer battery life, it is essential to take the utmost care of your battery. We are detailing out some important factors to keep in mind for maintaining your battery.

  • Keep an eye on the electrolyte level of the battery. Use distilled water if the fluid level is running low. The electrolyte level should be full about an inch from the top of the battery.
  • The level of the fluid solution increases when the battery is kept for charging. Hence, if we overfill the battery with distilled water prior to charging. the fluid level will rise and eventually would overflow, damaging the battery in the process.
  • Prevent the battery from corrosion. However, if the battery is already corroded, cover the corroded end with some baking soda. Pour water over it before scrubbing the area with a towel for 5-8 minutes. This would help you get rid of corrosion from your battery.
  • Another precaution you should take is not to overcharge your battery. Generally, there is a battery charging monitor installed in the RV to help you keep a check on the battery percentage. So, if you do not want to spend extra bucks on a new battery, make sure that you don’t charge the battery beyond the designated limit as this will not only significantly deteriorate the condition of the battery but also shorten its life.

Are there other alternative accounting methods that should be considered?

Some of the following methods are sound and easy to accomplish, perhaps even ecologically conscious. Others are downright dangerous and should only be used in an emergency.

Charging a 12-volt battery with jumper cables

To be blunt, this is a bad idea and should only be used in an emergency. I only mention it because I have seen many people try to improvise it when camping in the bush.

It’s most common with rustic tent campers who need to charge the 12 volt trolling motor batteries on their boat.

Just like jump starting a car, you connect black to black and red to red with a set of jumper cables. Then you start the vehicle’s engine.
Technically, some of the electricity generated by the alternator that is not consumed by the vehicle or the vehicle’s battery goes into the battery.

It helps if the radio, lights, and other electrical components in the vehicle are turned off.

Not only is this charging process very slow, but it also puts a lot of strain on the alternator. I did this with an F-150 pickup truck and got away with it.

I know someone who tried to do this with a hatchback and a few weeks later his alternator went out and had to be replaced at a cost of $350!

Can I charge my RV batteries with solar panels?

Absolutely yes! This is a great way to charge your 12 volt batteries while you are on the road.

It’s especially handy if you have a “two way” refrigerator, and you want to keep it running on electric while you’re driving an RV from point A to point B.

Many hardware stores sell them for very cheap. You just set them up in a generally south facing direction and let the photovoltaic cells transfer charge to the battery.

Remember, it’s more about taking the load off the battery than charging it.

The wattage delivered by consumer-grade solar panels is still pretty low, and it could take more than a full day to recharge a dead 12-volt battery.


At the end of this above discussion, we do not mean to say that before charging your RV battery, all the necessary information should be gathered from you. Usually, an RV has more than one battery. This is because of your convenience. But precaution or alternative should always be required to be ready. If you take proper care of your RV batteries, then you will never fall an undesirable situation.

I think this article will help you to gather enough knowledge on how to charge your deep cycle batteries properly. Have a great day!

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