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How Do I Charge My RV Battery?

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RV batteries can be charged in numerous different ways. If you’re unfamiliar with RV battery charger systems and want to get the best charge for your battery, you’re in luck. Our team of experts will share how to best charge your RV batteries.

How Do I Charge My RV Battery? 

Charging your RV batteries is essential if you plan to use your RV off the grid, but necessary even if using it at full hookup RV parks. Luckily, there are multiple ways to do it. 

battery in rv compartment near a "Arctic Ocean" sign

Having the right RV battery charger is vital; the type of charger will primarily depend on your RVing style and rig setup. There are several types of RV battery chargers, and the most common are converter chargers, inverter chargers, solar RV battery charge controllers, and multi-battery chargers. We’ll discuss each of these at length further on. 

Along with having the right charger type, you also need a power source. Power pedestals or electrical hookups are among the most common power sources, but RVers can also use solar panel systems, generators, wind power, and even your tow vehicle or RV’s engine. There are pros and cons to using each power source, which you can read about further down.  

Charging Lithium vs. Lead-Acid RV Batteries

The two most common types of RV batteries are lithium and lead-acid, both of which differ in performance and charging. 

You can bulk-charge lithium RV batteries up to 100%. However, a lead-acid battery can charge up to 80% in bulk charge mode. Then, it must enter absorption (charging at high voltage) from 80% to 95% and then float (maintain capacity without overcharging) from 95% to 100%.

In contrast, lithium batteries can continuously accept higher charge currents that charge the bank substantially faster. They never enter an absorption stage, so you can have full batteries in just a few hours. 

With lithium, you can also use your battery without a full charge because the battery output performance remains steady whether you’re at 95% or 20%. Lead-acid batteries require a full charge for optimal performance and their lifespan will be shortened if used to and at low discharge levels. 

Furthermore, lithium-ion batteries like our product line have a very low internal resistance that equates to much better efficiency. This means that whatever power you put in you get most of that out when using the batteries. With lead-acid batteries, there is significant losses that occur so you do not get near the same amount of power out as in. When charging with a generator or solar every drop of fuel and ray of sun counts and is best not wasted.

RV Battery Charger Types:

There are a handful of charger types we think are worth discussing when it comes to charging your RV battery. Read on for details about each. 

Converter Charger (AC charger)

In the RV industry, you will most commonly hear the built-in battery charger called a “converter”. This device is just a 120V to 12V converter similar to a car battery charger.

A converter charger takes alternating current (AC) power and converts it to direct current (DC) power. Incoming AC power to your RV converts to DC to power your major appliances and 12V system, and to charge your batteries.

All RV’s have a converter charger as it’s required for the DC system to work even when plugged in. It operates without you having to think about it and will likely be buried in the underbelly of an RV or mounted in a hidden location since you won’t need to access it regularly.

It’s important to know that a converter can convert the power but does not invert it. An inverter charger is another type of charger RVers often use.

converter charger diagram

Inverter Charger

RVers who use their RVs off-grid love inverter chargers. These are both chargers and inverters, which can invert 12-volt DC power into 120-volt AC power. This means that you can power appliances that run through your inverter charger from your RV battery bank.

While an inverter charger may allow you to use the microwave, watch TV, or use basic functions of the power inlets in your RV, they’re not perfect. Inverter chargers have a maximum amount of power that they can invert, which means being mindful of your electrical usage, depending on what you’re powering. When buying your equipment, do an energy audit to ensure your inverter charger can handle the load. 

inverter charger diagram

Solar RV Battery Charge Controller

A solar RV battery charge controller regulates power coming from solar panel(s) on your RV roof to your battery bank. The regulator prevents batteries from overcharging, which significantly extends their lifespan. 

A solar charge controller has a limit to the amount of power sent to your battery bank, so make sure you have the proper size charge controller to match your solar capacity.

solar charger diagram

DC-DC Battery Chargers

DC to DC RV battery chargers can be used when connecting one battery system to another. For example, connecting the house batteries in a motorhome to the chassis batteries would allow charging from the alternator to flow to the house batteries as well. DC-DC chargers are also used between different battery types, like lead-acid of a starting battery to lithium house batteries.

Multi-Battery Chargers

Most of the time when multiple batteries are used they are installed in series or parallel as one large bank. In these cases, the chargers mentioned above can charge all the batteries at once. Rare circumstances may require multi-battery chargers if the batteries are connected to different systems.

Power Sources for Charging Your RV

RVers can use several types of power sources for charging their RVs. If you enjoy using your RV off-grid, there’s a good chance you use more than one of the following power sources.

Shore Power Charging

Shore power charging is what many RVers commonly use when parked at a campground. This could be 15, 20, 30, or 50 amp power that uses a converter charger or inverter charger to feed your batteries.

You should always use a surge protector when on shore power, preferably with an EMS (electrical management system). This type of device protects your RV from power surges while preventing low voltage problems. 

fifth wheel rv at campsite with green trees

Generator Battery Charging

Generator battery charging uses the same charger as the shore power supply (a converter or inverter charger) but the power comes from a generator.

Some RVs come with onboard generators, while some RVers choose to carry a portable generator with them while RVing. Generators come in various sizes and with different power-creating abilities. The more watts a generator can produce, the more powerful it is. 

Many RVers planning to use an air conditioner or other high-powered appliances will shoot for a 3000-3500 watts generator. This offers plenty of power to run a single air conditioner during the warmer months or use the microwave or space heater.

Alternator Charging

When you’re charging your RV battery using alternator charging, you can charge your RV’s battery bank while driving. It’s best to use a DC to DC charger, which helps protect and extend the life of your RV battery and not overload your vehicle alternator. Most DC to DC charger models have the same three-stage charging modes that all chargers have, and it will safely charge the battery and prevent alternator damage.

Something to keep in mind: Using your alternator to charge your house battery often will wear out your alternator faster. You can preserve your alternator by using fewer amps and by charging your battery with shore or solar power as often as possible. 

Solar Power Charging

Solar power charging is a favorite charging style for those who love boondocking. Your batteries will be charging any time they’re not fully charged, and the sun is shining. Many RVers will roof-mount solar panels or use a portable panel to move around. 

This is an excellent option for those boondocking because there’s little to no maintenance required. You also won’t need gas on hand for your generator or worry about your battery power suddenly going.

12 volt RV solar system

What Is the Best Type of RV Battery Charger? 

The best type of RV battery charger will depend on your travel style and battery type. A multi-stage, programmable charger is typically the best as it provides the most flexibility and best charging for all battery types.

Do a little research and compare and contrast models to determine which is the best model for you. It takes a little time, but it’s less frustrating than your RV battery dying in the middle of a camping trip! 

Check out the Converters/Chargers for sale in our online store to get you started.

Want To Learn More About Electrical Systems and Lithium Batteries?

We know that building or upgrading an electrical system can be overwhelming, so we’re here to help. Our Reno, Nevada-based sales and customer service team is standing by at (855) 292-2831 to take your questions!

Also, join us on Facebook, Instagram, and YouTube to learn more about how lithium battery systems can power your lifestyle, see how others have built their systems, and gain the confidence to get out there and stay out there.

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