How to Charge a Campervan Lithium Battery

Updated on: November 2024

Lithium batteries are one of the most common types used in campervans. They provide more power than a standard car battery and can be charged with an external charger. If you own a campervan, it’s important to know how to charge your lithium battery properly.

This blog post will cover some information on what needs to happen before charging your caravan lithium battery for the first time, as well as some tips on how often you should charge your new lithium battery!

How Does a Battery Charge?

Lithium batteries are known to be one of the best power sources that can fit in a small area. You can find them powering devices such as laptops, phones and even vehicles. Lithium batteries can be charged through an external source using electricity from a generator, main power station, or your van’s starter battery. The lithium batteries used for charging campervans are known as “deep cycle batteries”. A deep cycle battery is rechargeable, which means it can be recharged multiple times. However, the number of charges a lithium battery can have will vary depending on its storage capacity and other factors.

The initial voltage surge, also know as the bulk charge stage;

The current phase, also known as the absorption stage;

The float stage.

Each stage is important for charging your battery and ensuring that it is not overcharged or damaged. Let’s go through each of these stages in more detail!

The Initial Voltage Surge:

Also known as the bulk charge stage. When you first connect your battery to a battery charger, a voltage surge happens as the battery starts to take in power. This stage can last anywhere from a few minutes to an hour.

The Current stage:

Also known as the absorption stage. The battery starts to take on a more steady power source. This stage can last for a few hours.

The Float stage:

This is known as the period where your battery should be left to charge for an extended period of time. This ensures that your lithium caravan battery gets all the power it needs and does not suffer from overcharge or damage when charging.

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3 ways to charge a leisure battery

The 3 most common ways to charge your lithium batteries are DC to DC charging, solar panel charging and a mains charger.

Each method has its advantages and disadvantages that should be considered when choosing the best way to charge your battery.

Charge your battery while driving

The easiest way to charge your lithium ion batteries is to use a DC to DC charger connected to your starter battery. This device can be installed into your engine bay or close to your auxiliary battery bank. It will charge your batteries as you drive.

This is an excellent option if you are on the move, as it means you don’t have to worry about finding an outlet to plug in your charger. It also means that you can drive while the batteries are being charged.

This option is not ideal if you are stationary for extended periods of time as the batteries may discharge before being charged again.

Campervan Solar Panels System

Solar panel systems for campers and RVs are another excellent way for charging your lithium batteries. Many campers have solar panels installed on the roof. If your camper doesn’t have one, you can easily add one to the roof yourself or buy a portable system that you can move around from vehicle to vehicle.

The type of solar panel system you choose should depend on how much power you need. If you only plan to use a few appliances while camping, then a small system should be enough. If you’re planning on using more power-hungry items, like a refrigerator or air conditioner, then you’ll need a more extensive system.

To charge your lithium batteries with solar panels, the main thing you need is sunlight. The amount of sunlight your solar panel system receives will determine how quickly your batteries charge.

Ideally, you want to place your solar panels in an area that gets full sun for most of the day. If you can’t find a spot like that, try to choose a location that gets at least several hours of direct sunlight each day.

You will also need a solar charger controller to protect your lithium ion batteries from overcharging. This device regulates the amount of power going into the battery, so it’s important to have one if you’re using solar panels to charge your batteries.

There are many different types of solar charger controllers on the market, so be sure to choose one that is compatible with your solar panel system.

Read our Best MPPT Charge Controller here.

240-volt lithium battery charger

If you don’t want to use a DC to DC charger or solar panel system, you can also charge your lithium batteries with a AC to DC lithium battery charger. This device plugs into your wall outlet and sends power to your batteries.

The lithium charger will charge lithium ion batteries much faster than a regular ac battery charger, so it’s a good option if you need to top up your batteries quickly.

Just like with the solar panel system, you’ll need an inverter to convert the 240 -volt power from the lithium charger into 12-volt power for your lithium batteries.

Battery configuration

Depending on how you connect your lithium batteries, in parallel or series, you will need a different configuration and a different charger.

To better understand the difference between them, I will explain how we use these configurations on our campervans.

Parallel Configuration:

This is what you usually see when someone connects their batteries in parallel. Multiple batteries positives are combined and the negative with negative terminals, sharing the same current. This configuration increases the usable capacity of your battery bank because it doubles or triples the amp hours rating but doesn’t change voltage. If one battery is discharged, the other will still have power.

Serieses Configuration:

When you connect batteries in series, you add voltage but not amps. So two batteries that are 12-volts 100 amps each connected in series will give you 24 volts but still only 100 amp-hours. If one battery is discharged, the other will not have power.

Series configurations are used when you need more voltage for your system.

You need to know which voltage your system is as it will affect which charger you choose as you may need a 24v or 12v charger.

Cables Size and Fuses

When charging your lithium batteries, you need to use the correct cables and size fuses. The wires need to be fitted with the correct size fuse for the amount of current that is being passed through them. If you don’t have the right sized fuses, this can damage your battery or charger.

Your lithium battery needs to be charged correctly. You will need either a purpose-built lithium charger or an inverter that has this facility to charge your batteries efficiently and safely.

It is crucial that when charging your lithium batteries, you use a fuse. A blown fuse will protect both the battery and the charger from damage. If your cable is not fused and you have a short circuit, this could cause irreparable damage to both your batteries and the charger attempting to charge them.

The correct size fuse for charging lithium ion batteries will depend on the lithium battery you have and how much current is being drawn from it—the smaller your batteries, the lower amperage fuse that should be used.

Cables Between The Batteries

The maximum discharge rate is important when determining what type of cable you will need. A higher amperage needs bigger cables in order to transfer all that current safely without overheating or burning out due to resistance during usage.

The best way to determine what size of cables you will need is by calculating the number of amps that needs to be transferred. The first step would be to check the maximum discharge rate on the manufacturer’s battery. Next is to check your highest drawing appliance. For example, an induction cooktop could draw 2000W.

To work out the max amperage draw is to use the below formula:

2000W/12 = 166 amp

If you have more than one battery, it is best to use the same size cable for all of them to ensure even charging and discharging.

Another thing to be aware of is that the number of amps your battery can discharge will limit how many appliances you can use at one time and how long they can be used. For example:

Your lithium battery has a max discharge rate of 120A. That means it could power two 12V appliances that use a maximum of 60A each for up to one hour.

However, if you have a large battery with a max discharge rate of 300A, it could power six 12V appliances with a maximum draw of 50A each for up to one hour.

Battery Management in Campervans

LiFePO4 batteries are very temperature sensitive. When discharged to a certain level, they can be damaged or destroyed. On the other side, Over-charging must be limited. Furthermore, the upper safety level for lithium battery technology cells is 4.2 volts. If this limit is exceeded, the cell becomes heated. This can lead to significant damage or even cell failure.

The best way of preventing these issues is by using an internal battery management system (BMS), which will monitor each cell’s voltage level, temperature, and overall state at all times. The battery monitor sends information wirelessly to an app on your phone, so you know how much charge you have left in your battery, how much time you have left to charge it and the state of each cell.

A BMS will also be able to detect when a cell has discharged beyond its safe limit (i.e., below ~20% SOC) by using voltage measurements on all cells and temperature readings from inside the modules.

Charging Limits & Monitoring

When it comes to charging limits, not everyone agrees. Most experts recommend keeping the discharge level at no less than 10% left of the total capacity. Some people advise against it and recommend only 20%, and it’s safer to charge to 90 percent instead of 100%.

The reason for this is that when you reach 100 percent, the charging process will top off the battery and send a current to it that’s greater than its maximum design rate. This could potentially cause damage to the cells.

It’s also important to note that while a advanced battery management system (BMS) can help protect your batteries from being overcharged, it’s not foolproof. There is always a chance that something could happen which will override the BMS settings and cause damage to your batteries.

Can I Charge a Lithium Battery with a Normal Charger?

Yes, you can charge a lithium battery with a normal charger (typical lead-acid battery charger) as long as the battery voltage and amperage are compatible. However, it’s important to note that charging a lithium battery with a lead-acid battery charger will result in a slower charge time. For best results, use a dedicated lithium caravan battery charger. Using a suitable charger will also protect your lithium battery from overcharging and prolong the battery’s life.

How do you Charge a Lithium RV Battery?

Battery charging on an RV camper van can be achieved with solar power or by plugging into a standard 240-volt power outlet or by installing a DC DC charger.

When charging your lithium batteries, it’s important to use the correct cables and size fuses. The cables need to be fitted with the correct size fuse for the amount of current that is being passed through them. If you don’t have the right sized fuses, this can damage your battery or charger.

It is essential for your safety to use a fused cable when charging your lithium charger is specifically designed for charging these types of batteries as they have a higher voltage than acid and AGM batteries. When charging with an RV inverter that does not have lithium dc battery chargers built-in, the inverter must be set to “battery mode” and the correct type of connector used to make the electrical connection between the inverter and the battery.