Camper van batteries are among the most critical and expensive additions to any van build. But batteries are also fragile technology, and a battery can die prematurely without a basic knowledge of proper battery maintenance.
While there are several aspects to a properly maintained battery, this article will delve into the #1 cause of a prematurely dead battery: keeping it outside its comfortable charge parameters.
Good to know: This information differs slightly depending on whether you have the standard lead-acid (and AGM) batteries or the newer lithium (LiFePO4) batteries. We will discuss both types in this post.
Proper Battery Charge Parameters
The #1 cause for batteries to die prematurely that we see while traveling in our camper van is people not keeping their batteries within the healthy charge range.
Most people think keeping a battery between 0-100% charge is fine. But this isn’t the case.
And depending on what type of battery you use, the healthy charge range can differ.
Healthy Charge Range
To maintain a healthy battery, it’s recommended to keep a battery’s charge percentage within the following ranges.
- Lead Acid (including AGM): Healthy range = 50%-100%
- Lithium: Healthy range = 20%-80%
Forcing batteries outside these healthy ranges for too long and too many times reduces the battery’s total number of cycles before dying (i.e. when the battery refuses to hold a charge).
AGM batteries: Avoid letting your lead acid (and AGM) battery drop below 50% charge when using. Letting this happen a few times is fine, but it’s detrimental to the battery’s lifespan if the charge drops below 50% consistently or daily. On top of this, make sure your AGM batteries are regularly charged to 100% to prevent permanent sulfation of the battery plates.
Lithium batteries: Try not to let your lithium batteries drop below 20% charge as this also reduces their life expectancy. But just as important, do not constantly charge your batteries above 80%, as this stresses them and prematurely wears them out.
How To Monitor a Battery’s Charge?
But monitoring a standard 12V battery’s percentage charge isn’t as easy as you might think.
Please read to learn more as we discuss how to keep on top of your battery’s charge in the next chapter.
How To Calculate a Battery’s SOC
A battery’s “state of charge” (SOC) measures how much charge remains in that battery when compared to its nominal capacity. It is essentially a battery’s % charge.
Determining your phone or laptop battery’s SOC is easy. Look for the battery percentage displayed on your screen.
However, determining a standard 12V battery’s SOC is trickier since there is no convenient screen displaying the battery’s % charge. Luckily, finding out your battery’s SOC is still possible using one of two methods.
- The budget way with a multimeter
- The convenient way with a battery monitor
The Budget Way
Using a multimeter, you can determine the battery’s voltage. Set up the device to measure voltage and connect the device’s positive & negative receptors to the corresponding battery terminal posts. The multimeter will give an instantaneous readout of your battery’s voltage.
Once you know the voltage, you can use a voltage-to-SOC chart to estimate your battery’s SOC.
Below are two charts (one for AGM and one for lithium batteries) to determine your battery’s percentage charge from its voltage reading.
Important: Knowing which type of battery (Lead Acid or Lithium) you are taking the voltage measurement from is crucial. The SOC will differ based on which type of battery it is.
AGM & Lithium Battery Voltage Chart
Refer to the below tables to determine your battery’s state of charge based on its output voltage.
For those on a budget, using a digital multimeter is a great and accurate way to monitor your battery’s state of charge.
The biggest downside of a multimeter is that you always have to take it out and set it up to check a battery’s voltage. It takes time and is cumbersome. But it works.
Digital multimeters are a great way to get electrical readings all throughout the van's electrical system. They display battery voltage, measures DC current, and can help troubleshoot many electrical issues that you might incur in the future.
The Convenient Way
You can quickly check your battery’s percentage state of charge by hard-wiring a battery monitor into your electrical system. The battery monitor continuously monitors the voltage and automatically displays a percentage charge.
We use the Victron BMV-712 battery monitor to keep track of our battery’s state of charge. We love this handy device and recommend it to anyone building a camper van concerned about proper battery maintenance.
This device is one of the very few that is Bluetooth enabled. This means you can connect your smartphone to this monitor and, when using the Victron app, can conveniently keep track of your battery’s state of charge at all times.
Prolong your battery's lifespan. Knowing your battery's state-of-charge (SOC) is a critical factor in preventing it's premature death. This monitor displays percentage charge, voltage, instantaneous power flow, and more. Bluetooth capable means easy connection to any smartphone.
Why Is Proper Battery Maintenance Important?
Maintaining a healthy battery charge is essential for the following reasons:
Prevent Battery Degradation
The standard 12V battery is quite fragile. Without proper care, these batteries can quickly degrade in their charge and ability to provide power to external devices when required.
One of the significant downsides as the battery degrades is that the amount of charge a battery can hold declines. Therefore, the battery will be able to distribute less charge to external devices before recharging.
Battery degradation is natural and happens to all batteries. However, we can prevent premature battery degradation by practicing good charging and discharging techniques.
Prevent Unexpected Battery Failures on the Road
Sadly, dead campervan batteries are uncommon within the van life community. Dealing with dead batteries while driving in an urban setting is one thing. But having a battery fail on you while boondocking miles from civilization can be a real headache. Prevent this from happening by practicing proper battery maintenance.
Saves Money in the Long Run
Batteries are expensive! A standard 12V, 100Ah lead-acid AGM battery typically sells for about $180-$300. An equivalent lithium (LiFePO4) battery costs between $350 and $950.
Practicing good battery maintenance prevents you from getting a dead battery while traveling and saves you money by not having to buy new batteries prematurely.
Proper Battery Charging Tips
As we learned, different battery chemistries like to float between different charge parameters. These differences mean different charge strategies apply when utilizing these batteries.
Let’s take a look below.
Lead-Acid & AGM Battery Charge Maintenance
- Prevent the battery from falling below 50% charge
- Keep battery at full 100% charge whenever possible
- For vehicle starting batteries, use a trickle charger to maintain charge.
Battery Trickle Charger
We use a trickle battery charger to keep our camper van’s starting battery charged and healthy when shore power is available. This is especially useful when we store our van for long periods of time.
Proper Lithium Battery Charge Maintenance
- Prevent the battery from falling below 20% charge
- Do not consistently maintain the battery above 80% charge
- For long-term storage, charge to 60% and unplug all parasitic loads
Happy Batteries = Happy Van Life
Campervan batteries can be finicky things! Charging them too much or letting them discharge too low can adversely affect their lifespan and ability to power their electronic devices.
But by learning the basics of proper battery maintenance and charging principles, we can keep our batteries healthy, happy, and with as prolonged a life as possible.
And with adequately functioning batteries, we can travel longer to explore more of this beautiful planet!
Please let us know in the comments section below if you have any questions about maintaining a camper van leisure battery.
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