Camper van batteries are one of the most important and expensive additions to any van build. But batteries are also fragile pieces of technology and a battery can die prematurely without a basic knowledge of proper battery maintenance.
While there are a number of different aspects to a properly maintained battery, this article will delve into the #1 cause of a prematurely dead battery; keeping the battery outside it’s comfortable charge parameters.
Caveat: This information differs slightly depending on whether you have the common lead-acid (and AGM) batteries or the newer lithium (LiFePO4) batteries. We will discuss both types in this post.
Let’s get started!
Proper Battery Charge Parameters
Lead Acid (AGM) & Lithium (LiFePO4)
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 that keeping a battery anywhere between 0-100% charge is fine. But this actually 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 Batteries (including AGM): Healthy range = 50%-100%
Lithium (including LiFePO4): Healthy range = 20%-80%
Forcing batteries outside of these healthy ranges for too long and/or for too many times reduces the battery’s total number of cycles before dying (i.e. when the battery refuses to hold a charge).
Key Takeaway
For AGM batteries: Try not to let 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 is dropping below 50% on a consistent or daily basis. On top of this, make sure your AGM batteries are regularly charged to 100% to prevent permanent sulfation of the battery plates.
The blog Practical Sailor has a great post discussing the importance of regularly topping up an AGM battery to prevent premature death.
For 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 keep your batteries constantly charged above 80%, as this stresses the batteries and prematurely wears them out.
Over at CleanTechnica, they also reinforce the detrimental effects of keeping a lithium battery consistently charged at 100%.
How To Monitor A Battery's Charge?
But monitoring a standard 12v battery’s percentage charge isn’t as easy as you might think.
Keep reading to learn more as we discuss how to keep on top of your battery’s charge in the next chapter.
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How To Calculate A Battery's SOC
A battery’s “state of charge” (SOC) is a measurement of how much charge is remaining in that battery when compared to it’s nominal capacity. It is essentially a battery’s % charge.
Determining your phone or laptop battery’s SOC is easy. Simply look for the battery percentage displayed on your screen.
But for a standard 12v battery, determining it’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
- The convenient way
Method 1:
The Budget Way
Using a multimeter, you can determine the battery’s voltage. Simply set up the device to measure voltage and connect the device’s positive & negative receptors to the battery’s pos. & neg. 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! It's crucial to know which type of battery (Lead Acid or Lithium) you are taking the voltage measurement from. The SOC will differ based on which type of battery it is.
AGM Battery Voltage Chart
Find your AGM battery’s voltage to calculate it’s state of charge.
Lithium Battery Voltage Chart
Find your lithium battery’s voltage to calculate it’s state of charge.
Digital Multimeter
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.
Method 2:
The Convenient Way
By hard wiring a battery monitor into your electrical system, you can easily check your battery’s percentage state of charge. The battery monitor continuously monitors the battery voltage and automatically displays a percentage charge.
Building A Camper Van?
We detail how to install this battery monitor in our camper van electrical system installation guide.
Battery Monitor
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 who is building a camper van and 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.
Victron BMV-712
- Bluetooth Enabled For Smartphones
- Fast & Convenient
- Monitor Energy Flow
Why Is Proper Battery Maintenance Important?
Maintaining a healthy battery charge 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 distribute 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
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 (LiFePO4) 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
As we learned, different battery chemistries like to float between different charge parameters. And these differences mean different charge strategies apply when utilizing these batteries.
Let’s take a look below.
Lead-Acid & AGM Battery Charge Maintenance
- Prevent 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.
Stanley Battery Charger
- Maintains AGMs @ 100% charge
- Low cost & effective
- Great for long-term vehicle storage
Proper Lithium Battery Charge Maintenance
- Prevent 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
Was This Van Life Tip Helpful? We have lots of other useful articles to help you travel better in your camper van or RV. Check out our hacks & tips page to read more great van life content!
Building a camper van? Download our free e-Books with intuitive electrical, solar, and plumbing diagrams.
Happy Batteries = Happy Van Life
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 proper battery maintenance and 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!
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