How to Charge a LiFePo4 RV Battery

How to Charge a LiFePo4 RV Battery

Lithium batteries have become a go-to source for powering up camping life. They are lightweight, more efficient, safer, and have better performance and energy density. The question that many RV owners ask is how to charge a LiFePo4 RV battery.

Lithium-ion battery chemistry is difficult enough to attract misleading information on the internet. To remedy that, we decided to provide our readers with accurate information about charging RV batteries.

The article provides the best methods to charge LiFePo4 RV batteries for both indoor and outdoor charging. Make sure to read the safety instructions at the end to avoid any unwanted incidents.

Methods to Charge LiFePo4 RV Battery

In summary, below are the safest methods you can use to charge your house battery.

  • Shore Charging
  • Solar Charging
  • Generator Charging
  • Vehicle Alternator

We’ll discuss each method in detail for your 12V deep cycle RV battery and equivalent since these are the most common types used in RVs.

Shore Charging

The fastest and easiest method to charge your RV battery is by connecting with the grid. Your work is simple if your vehicle has a converter that changes AC power to DC power. In that case, you can simply plug in the power cable to the 120V electrical outlet and start charging.

If you don’t have an AC/DC converter, you’ll need a charger to connect to the grid. Be careful when selecting a charger because there are many types out there in the market. You may get one as cheap as thirty bucks but it’ll take forever to fully charge your batteries.

Also, you need to match your battery specs with the charger. Do not try to use a lead-acid battery charger as it may damage your lithium rv battery. The better of the two options is to use a specific charger for your RV battery.

If you don’t have a power plug installed in your vehicle then you can check this tutorial out for installing it by yourself.

Solar Charging

How to Charge a LiFePo4 RV Battery

The next method is to charge the batteries using solar panels. Solar energy is the greenest option but you may already know that it’s a little expensive to set up. Not just that, you’ll also need to install solar panels on your RV and use a suitable converter to charge the batteries faster.

You may need to replace your converter because most factory-installed converters are not compatible with lithium batteries.

The equipment you need to charge your batteries on the road includes:

  • Solar panels
  • Charge controller
  • AC/DC inverter

Installing solar panels may seem a complicated task but if you’re passionate, you can do it yourself.

Kevin Bowen of the RV Addict shows all the steps in the below video if you want to install the panels and the charging system so you can DIY.

Generator Charging

How to Charge a LiFePo4 RV Battery

Most RVs have a generator onboard for emergency purposes. If you have one with you, it can help you charge your rv lithium battery. This method of charging is not without problems as produces a lot of noise and runs on fossil fuels which is not ideal for the environment. However, for emergencies, it can be of great help to campers.

If you’re planning on buying a generator then you should buy an inverter generator. The cost is not too high for these modern generators when compared with the benefits. These generators mostly come with a 12V outlet. If not, you’ll need a converter.

Remember that charging with a generator is only for semi-emergency situations as frequent charging with generators is not good for your battery health. Also, charging with generators is not as fast as using a house charger.

The geeks may head toward the following videos to get in-depth knowledge about amps, volts, and watts.

Vehicle Alternator

How to Charge a LiFePo4 RV Battery

If you’re smart, you may wonder if your alternator can charge your vehicle starter battery, why can’t it charge your lithium batteries in case you need it? You’re right!

An alternator uses power from the generator to charge the battery. With the right components, you can use it for a LiFePO4 rv battery charger These include:

  • Battery isolation manager 
  • Battery to battery (DC to DC) charger
  • Alternator protection device

You might have heard about alternator damage when charging lithium batteries. Make sure to use an alternator protection device to protect your alternator. This problem does not exist with lead-acid batteries though.

Note that the charging from the alternator will be slow and not a desired power source for your batteries.

Safety Tips for Charging LiFePo4 RV Battery

To protect the battery from damage and yourself from accidents, there are certain safety guidelines you must remember. Here are some safety tips for long battery life and safe charging:

  • Don’t charge unattended
  • Charge the battery in a ventilated place
  • Avoid extreme temperatures
  • Use standard cables and extension cords
  • Use a dedicated charging circuit
  • Follow proper disconnection procedures
  • Store and transport safely
  • Use a LiFePO4 battery charger
  • Follow the manufacturer's guidelines
  • Avoid overcharging

Note that you can charge your battery in the RV as long as you take the proper precautions mentioned above.

How Long Do Rv Batteries Last

A properly maintained deep cycle battery should last 6 years or more. Unfortunately, some caravan owners replace their batteries every year or two. Extending the life of a battery is not difficult and only requires some basic care and maintenance.

How do I know if my RV needs a new battery?

If the battery is not fully charged or is charging at a low rate, then the battery may be faulty and needs to be replaced. A good rule of thumb is to replace the caravan battery approximately every 5 years.

How To Hook Up Solar Panels To Rv Batteries

Solar electric systems for RV vary considerably, especially if installing larger systems, make sure you are confident with the wiring before you install. For systems or kits up to several hundred watts, the voltage is not dangerous and can be installed by anyone. Regardless of size, the following instructions are advanced instructions on how to wire components. 

Assume you have purchased a kit that contains components for a solar panel system and you have a battery or battery pack installed in your RV.

Your kit will contain:

Solar panel (or multiple, depending on what you choose to purchase).
Charge controller.
Wiring harness (and possibly connectors, adapters and mounting brackets)

How Long To Charge Rv Battery When Plugged In

Depending on how low the battery level is, it will take at least 10 hours to recharge your RV battery. If the battery level is well below 50% and you want to charge it to 100%, you may need 24 hours or more to complete the charge.

How Many Batteries To Run Rv Ac

In order to run a battery-powered air conditioner for 8 hours, you will need a large number of batteries. You may need around 16 to 20 fully charged deep cycle batteries with a charge time of 100 amps each to run two air conditioning units for 8 hours. By comparison, you would need 8 lithium batteries at 100 amps each.

FAQ Charge a LiFePo4 RV Battery

1. Can I charge a LiFePO4 battery with a normal charger?

Charging a LiFePo4 battery with a normal charger is not a good idea. These batteries require specific power parameters to ensure proper charging which leads to longer battery life and better performance. Using a charger designed for lead-acid batteries may result in overcharging or undercharging, thus damaging the battery.

Specific LiFePo4 chargers are designed with particular voltage and current settings to keep the battery safe and performance maximum. Lithium batteries are much more efficient but they are also not that cheap. Using a substandard or unsuitable charger may save you some bucks but this is not a wise choice.

2. What voltage should I charge my LiFePO4 battery?

LiFePo4 batteries come in different configurations so you’ll need to read the instructions carefully before charging your battery. However, a typical LiFePo4 requires 3.6 to 3.8 volts per cell. That means, in a 12V battery system, consisting of four cells, you’ll need around 14.4 to 15.2 volts.

Maintaining the proper voltage is essential to preserve your batteries so make sure you read all the specifications of your battery system. Also, use a charger compatible with those specs and use converters whenever necessary.

3. How many amps does it take to charge a LiFePO4 battery?

The amps required to charge the LiFePO4 RV battery depend on the battery capacity. Typically, the recommended charging current is around 0.2C to 0.5C, where C is the capacity of the battery. For example, if you have a 100Ah capacity LiFePo4 battery, the recommended current would be between 20A to 50A.

Note that the charging current should not exceed the maximum limit provided by the manufacturer. Exceeding the limit may cause damage to your battery. Again, your charger should match the current specifications to safely and fully charge your battery.

4. How long to charge a lithium battery for the first time?

You don’t need to charge the battery for an extended period if you’re charging your LiFePo4 RV battery for the first time. However, you’ll need to be careful if you’re charging cells in parallel. The first charge should be done with a low current (max 0.5C). Check the volts of each cell to make sure they have the same voltage.

Clean the terminals, align them with positives and negatives on one side, and connect them with connectors in parallel. Don’t connect both terminals of the charger to the first cell. Instead, connect them on the opposite side of the first and last cell to ensure even charging. When the charging is full, the charger will turn off automatically.

5. Can I leave my LiFePO4 battery connected to the charger all the time?

It is generally not recommended to leave your LiFePO4 battery connected to the charger continuously. LiFePO4 batteries, like any other rechargeable battery, can be damaged if overcharged. Overcharging can lead to increased heat generation, reduced battery lifespan, and potentially even safety hazards.

Once the battery is fully charged, it's best to disconnect it from the charger to prevent overcharging and potential damage to the battery. Most RV battery chargers for LiFePo4 batteries turn the charging off once the battery is fully charged. Still, after fully charging the battery, you should disconnect it from the charger.

Final Thoughts

LiFePo4 batteries have a high energy density, long cycle life, and improved safety features compared to other lithium-ion batteries.

To charge a LiFePo4 RV battery, you'll need a charger specifically designed for LiFePo4 batteries. It's not advisable to charge a LiFePo4 battery with a regular lead-acid battery charger, as it cannot charge the LiFePo4 battery to its full capacity.

Before charging, set the charger parameters according to the manufacturer's guidelines. Remember that the LiFePo4 RV battery performs best when you use it according to the manufacturer’s guidelines.


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