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RV Battery Charging 101

Not really sure how RV batteries work? You’re not alone! RV batteries, and RV electrical systems as a whole, are incredibly complicated and oftentimes difficult to wrap your mind around! We here at All Seasons are making it easier to understand by providing you with some simpler information in this RV battery charging 101 post, so that you can always have your RV batteries properly charged up and ready for anything!
Understanding Voltage

The key to fully understanding RV battery charging is to be able to make sense of voltages. RV batteries run on 12 volt DC (direct current) deep-cycle electrical energy. This can be enough to power some smaller RV systems and appliances, but not all of them. These deep-cycle batteries are designed to discharge and recharge over and over without damaging the battery. Batteries are measured in amp hours, which means one amp drawn for one hour, and in cases for most batteries, over a 20 hour period.

These 12 volt batteries are used to charge certain systems throughout your RV, which are specially designed to run on 12 volt power. Many times when you aren’t relying on your RV’s batteries for power, you’ll be plugged into shore power, which is 120 volts of AC (alternating current) power. This can provide more power to more of your RV’s systems, but can also be used to charge your RV batteries!

Charging RV Batteries With 120 Volt Power

When batteries discharge, or lose power, they will not recharge themselves like automotive batteries do. You will have to be responsible for monitoring your RV battery levels, making sure that the charge doesn’t fall too low.

When it’s time to charge the RV batteries, you’ll simply want to plug your RV into a 120 volt AC outlet, such as ones found at your home or campground. Since these outlets put out the 120 volts of AC power instead of 12 volts of DC power that your batteries require, you’ll need to make sure that your RV has a power converter! Most newer model RVs come standard with these today, but if you have a used RV, you’ll want to make sure you have one of these to avoid disastrous electrical issues!

Using shore power with a converter can take hours if your battery is depleted or on a low charge. Even though this is normal, it can be frustrating if you are needing power ASAP.

Solar Power

Instead of relying on electricity to power your batteries, use a solar power system to do the job! There are numerous advantages, as well as some disadvantages, to using solar power, but it’s especially fantastic for boondocking and dry camping! Instead of plugging your RV into an electrical source, solar panels convert sunlight into power, which is stored in your battery for later use to power your RV’s systems.

Solar power can be very tricky, especially if you aren’t aware of how much power you use in your RV! Because sunlight isn’t as plentiful as shore power, you’ll only have so much time per day to charge your batteries, and what you end up with at the end of the day is what you have to work with. This can take some careful planning about what items to use when, and is inspiration to calculate the best angles during particular seasons for optimal sun exposure and energy retention.

Stand-Alone Battery Charger

If you’re concerned that you won’t be able to easily keep up with RV battery charging when your RV is in storage, or that you can’t protect the battery from extreme temperatures, you may want to completely remove the battery(s) from your RV for the off season. If you do this, it will not be as easy as plugging in your RV to shower power in order to charge the batteries!

Instead, you’ll have to use a battery charger, which can be found at any automotive store. These are actually pretty handy for easily monitoring your battery’s levels as you charge! For the first 90 percent of charging with this method, you can use a higher power output, which is called bulk charging. For the remaining 10 percent, a lower power output is used, called absorption charging, and is used to prevent gassing and water loss. Finally, float charging is used to help keep the battery fully charged. From there, you’re good to go without using shore power!


Unfortunately, charging and using RV batteries isn’t as easy as charging a cell phone. It takes constant vigilance and action to ensure that batteries don’t discharge too much. If you let your RV fall too far below its necessary voltage, it can be susceptible to something called sulfation, which is the buildup of lead sulfate crystals.

Sulfation can cause an array of problems for your RV’s battery, including prolonged charging time, and ultimately, premature failure. There are two different types of sulfation, called reversible and permanentsulfation, which can be good and bad news. You can reverse some sulfation if it is caught early enough by administering a controlled overcharge of the battery, but this should be handled by a professional. This extra charge helps to dissolve crystals and return the battery back to a fully-functioning state. On the other hand, if the battery falls victim to permanent sulfation, there is no reversing the damage.

The onset of permanent sulfation is triggered by low battery charge that continues for extended periods of time. That is why RV batteries should be kept above 20 percent (or 12.4 volts) charge remaining. Anything lower than that and your battery will suffer the consequences of sulfation. In fact, letting your battery discharge down to 50 percent will provide the longest life span for your deep cycle batteries.

Other Battery Charging Tips

Charge your RV batteries frequently, even when not using your RV. Just because you aren’t actively camping in your RV doesn’t mean the rig isn’t drawing out battery energy! Either remove batteries from their compartment and store them in a cool, dry place and recharge, or plug your RV into shore power for about 8 hours. Do this at least once a week, and always be sure to check battery levels often!

Know your RV system’s amp usages. In order to calculate how much power you are using and how long your power stores will last while running certain features, you’ll want to find out just how much each feature uses.

Never let your battery discharge below 10.5 volts. Yes, we said 12.4 volts above, but that level doesn’t guarantee a swift onset of sulfation. But when you allow your battery to fall down to 10.5 volts, the chances for permanent sulfation drastically increase.

Check water levels occasionally. It’s important to keep a certain level of water in your battery, so be sure to check it every once in a while. Check prior to charging, and if the levels are fine, proceed with charging once the caps have been replaced. If you notice that the water levels are lower than the plates before charging, use only distilled water to fill the reservoir only to the point where water just covers the plate. Do not use any water with minerals in it, including tap water, as it can cause damage to the battery.

Utilize Battery Disconnect. To prevent unnecessary battery draining when your RV is in storage, make sure to flip the battery disconnect switch. This will prevent systems from inadvertently drawing power out of the batteries while in storage.

Do you have a better idea on how to charge your RV’s battery now? It’s a complicated system for sure, but well worth it to know, especially if you’re into boondocking and dry camping! Hopefully this RV battery charging 101 crash course has helped to make things clearer! As always, if you have any questions, don’t hesitate to call us here at All Seasons RV!

If you’re in the market for a new or used RV that’s perfect for dry camping adventures, All Seasons RV Supercenter has exactly what you’re looking for, with prices that you can definitely get on board with! We have one of the best RV selections in West Michigan, and will work with you to find a travel trailer, fifth wheel, or toy hauler with great battery capacities to fit your adventurous lifestyle! We even offer fantastic no-money-down financing so that RVing is more affordable for everyone!

Leave us a comment with any other battery insights or if you have any additional questions!

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