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Proper Campervan Battery Charging Tips

Campervan batteries are one of the most important and expensive additions to any campervan. We need these batteries to power our lights, our fridge, and all the rest of our electrical devices. But batteries are also fragile pieces of technology and without a basic knowledge of battery charging techniques, a battery can die prematurely. Follow these battery charging tips to learn more.

In this article, we will discuss proper campervan battery charging tips and safe depth of discharge (DoD) levels. This information differs whether you have the common lead-acid batteries or newer lithium batteries, and we will discuss both types in this post.

Let’s get started!

Table of Contents

AGM vs Lithium-Ion Batteries
Lithium-Ion Battery (Left) and Lead Acid AGM Battery (Right)

What Is A Battery's State-of-Charge (SOC)?

A battery’s “state of charge” (SOC) is a measurement of how much energy is remaining in that battery. On your phone or on your laptop, it’s easy to determine your battery’s SOC; simply look for the battery percentage displayed on your screen.

For a standard 12v campervan battery, determining it’s SOC (or charge percentage) is trickier since there is no convenient display screen. But finding out your battery’s SOC is still possible using one of two methods.

Multimeter

Using a multimeter, you can determine the battery’s voltage. Once you know the voltage, you can use a voltage-to-SOC chart to estimate your battery’s SOC.

Below are charts to determine your battery’s percentage charge from it’s voltage reading.

Battery Charging Tips - Lead Acid SOC Chart
Lead Acid SOC Chart
Battery Charging Tips - Lithium Battery SOC Chart
Lithium Battery SOC Chart

Battery Monitor

By hard wiring a battery monitor into your electrical system, this device can measure your battery’s voltage and automatically calculate the percentage SOC for you. We detail where this battery monitor needs to be installed in camper van electrical system installation guide.

At around $200, our battery monitor is one of the more expensive models out there on the internet, but it is one of the only models that is Bluetooth enabled and comes with it’s own smartphone app. This makes checking our battery’s SOC from our phones quick and easy.

Campervan Electrical System Installation Guide
Build Your Van's Electrical System

What Is Depth-of-Discharge (DoD)?

Depth of discharge measures how deeply a battery is discharged. So if your battery shows that it is 60% full, then it’s discharge is 40%.

Lead acid and lithium batteries differ on save levels of DoD. Typically a lead acid should only achieve a maximum of 50-60%. Lithium batteries can be discharged has much as 80-90%.

In order to maintain a healthy battery, it is crucial to stay within the safe DoD levels, which depends on the type of battery you have.

We will discuss this further below.

Why Is Maintaining A Healthy Battery Important?

Maintaining a healthy battery is important for the following reasons:

1. Prevent Battery Degradation

The standard 12v battery is actually quite fragile. And without proper care, these batteries can quickly degrade in the amount of charge they hold and their ability to provide power to external devices when required.

One of the major downsides as a battery degrades is that the amount of charge a battery can hold declines. Therefore, the battery will be able to give less charge to external devices before needing to be recharged.

Battery degradation is natural and happens to all batteries. But we can prevent premature battery degradation by practicing good charging and discharging techniques.

2. Prevent Unexpected Battery Failures On The Road

After a certain point, a seriously degraded battery dies. This means that the battery simply cannot hold any meaningful charge anymore.

Preventing battery failure while traveling on the road is the biggest reason for proper campervan battery maintenance, since not having electricity to power our electrical devices can really hamper quality of life on the road. Sadly, dead campervan batteries is not an uncommon issue within the van life community.

3. Saves Money In The Long Run

Batteries are expensive! A standard 12-volt, 100ah lead-acid AGM battery typically sells for about $180-$300. And an equivalent lithium iron phosphate battery goes for between $700-$950.

Practicing good battery maintenance not only prevents you from getting a dead battery while traveling, it also saves you money by not having to buy new batteries prematurely.

Proper Battery Charging Tips

Surprisingly, different battery chemistries require different maintenance techniques. Depending on if you have a traditional lead-acid battery or a newer lithium-iron battery, how you charge your battery and how much you can regularly discharge those batteries are different.

Let’s take a look below.

Lead-Acid & AGM Battery Maintenance

Affordable and dependable, lead-acid batteries (and their AGM cousin) have been the traditional battery solution for campervan travelers for years.

Let’s take a look at best charging practices for these lead-acid type batteries.

Safe Depth-of-Discharge Levels

Proper Battery Charging Tips - Lead Acid and AGM Battery Voltage Chart
Lead Acid Battery SOC Chart

In order to keep lead-acid batteries healthy and working for their rated number of charge cycles, it is crucial to keep the battery’s DoD within safe parameters.

In the case of lead-acid batteries, making sure the battery’s DoD does not fall below 50% will ensure a healthy lifespan of the battery. Falling below 50% too many times will significantly shorten the battery’s lifespan.

Charging Strategies

Lead-acid battery’s love to be charged and stored at 100% for as long as possible.

This means keeping your battery’s SOC topped up through a combination of solar power, shore power, and by connecting the batteries to your vehicle’s alternator is beneficial to maximizing the longevity of the battery’s lifespan.

Proper Lithium Battery Maintenance

Lithium batteries are quickly becoming more popular in the van life community as they are able to safely discharge to lower levels than lead-acid batteries (80% vs 50%). However, lithium ion batteries are considerably more expensive and, perhaps, more finicky in how they are safely charged.

Safe Depth-of-Discharge Levels

Proper Battery Charging Techniques- Lithium Ion Battery
Lithium-Ion Battery SOC Chart

Unlike lead-acid batteries, a lithium-ion battery can be discharged down to as low as 20% without significantly reducing the lifespan of the battery. And this has been very beneficial to the campervan community since availability of power is always in limited supply.

Charging Strategies

One of the downsides of lithium-ion batteries is that keeping the battery constantly charged to 100% stresses the battery out and decreases the lifespan of the battery.

If you can help it, keeping a lithium battery’s SOC between 30%-80% helps keep the battery healthy and prolongs it’s lifespan.

During the charging process, once our lithium battery’s SOC arrives at 80%, we usually disconnect the solar and let the batteries drain down to around 30%, then we will reconnect the solar to start the charging process again.

If we need to charge quickly or there is no sun in the forecast, we will connect our lithium batteries to our vehicle starting battery to charge them while we drive.

Once a month we will charge our batteries back up to 100% as a reset.

Related Articles:

Happy Batteries = Happy Van Life

AGM vs Lithium - Lithium Batteries Are Better For Us

Campervan batteries can be finicky things! Charge them too much or letting them discharge too low can have adverse affects on their lifespan and their ability to power your electronic devices.

But by learning the basics in campervan battery charging principles, we can keep our batteries healthy, happy, and with as prolonged a life as possible.

And with properly functioning batteries, we’re able to travel longer to explore more of this beautiful planet!

Go Back: DIY Camper Van Build Guide

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