Understanding Campervan Leisure Batteries
The most critical part of any campervan electrical system is the leisure battery. Think of it as the bigwig of the van life world. However, this doesn’t mean choosing the best campervan leisure battery needs to be difficult and stressful.
This guide will run through everything you want to know about campervan batteries. So you can stop tearing your hair out, make a brew and settle in. If you’re not much of a fan of reading, skip to our summary.
What is a Campervan Leisure Battery?
Before we go any further, it’s worth noting that leisure battery is a term used to describe the battery that will power the appliances in your van conversion. This is in comparison to the starter battery, which is part of your van already and used to start the van when you turn the key in the ignition.
How A Campervan Leisure Battery Works
Campervan leisure batteries work by storing electrical energy as chemical energy, the same as any other type of battery. This electrical energy can be provided by your solar panels, your battery-to-battery charger or your 240V hook-up – your batteries won’t even know the difference.
Here is a breakdown to explain more:
- All batteries work by creating a potential difference (i.e. Voltage) between 2 terminals, a positive and, you guessed it, a negative.
- When the battery is charging, charged particles (or ions if you want to get all sciencey) move from the positive terminal to the negative terminal.
- Then, when you switch on an appliance, electrons will flow through your electrical system from the negative battery terminal, through the appliance and back to the positive battery terminal, where they’re ready to be charged back up again.
Leisure Battery Capacity
Explaining Amp-hours (Ah)
We describe how much energy a battery can store by using the unit Amp-hours (Ah) which is a current flow of 1A for 1 hour. So a battery with a 100Ah capacity could sustain a current flow of 100A for 1 hour, 1A for 100 hours, or 5A for 20 hours – you get the idea.
How much capacity will I need?
What leisure battery capacity you need will be dictated by how much power you need in your van. For example, if you’re a digital nomad who needs to work from your van, you’ll need significantly more battery capacity than if you’re a day tripper who might need to charge your phone but not much else.
This can be pretty tricky to figure out, but luckily for you, our team at Vunked has done the hard work and created a Campervan Electrics System Builder, which can be found below. When using the tool, select the appliances you’d like to use off-grid and then build your system until you have exactly what you’re looking for.
The importance of getting the leisure battery capacity right
It’s essential to get your battery capacity right for how you want to use your van. If you don’t have enough battery capacity for all the appliances you want to run, you’ll likely struggle, regardless of how many solar panels you have or how long you drive.
Leisure Battery Charging Cycle
How does this work?
The batteries in your campervan work precisely the same as those in your phone. So when you use your phone throughout the day, whether for a YouTube van conversion binge or to send loving messages to your significant other, this activity will discharge your batteries.
When you get home at night and plug your phone in, the battery will start to recharge, completing what we call a battery charging cycle. Therefore, when we do this repeatedly, the battery will eventually begin to degrade, and you won’t be able to spend half as long scrolling before you need to plug in.
What happens when I reach the maximum 'number of cycles'?
When we buy batteries for a campervan, they all have a lifetime described as the ‘number of cycles’ before the battery degrades in the same way as your phone!
The good news is that your campervan leisure battery won’t just stop working when it reaches this number of cycles, but it will start to degrade and won’t hold its charge quite as well as it used to. This will gradually worsen until you’re unable to spend time off-grid without replacing it.
Leisure Battery Depth Of Discharge
How does this work?
Have you ever had the starter battery on your car run flat and needed a jump start from a friendly stranger? With this in mind, you might have noticed that your battery hasn’t held its charge quite as well as before. This is because your battery has been discharged much deeper, and fully discharging it can degrade it!
What to look out for
Therefore, depending on the battery technology you opt for, there may be a recommended limit on how discharged you can allow the campervan leisure batteries to get without doing permanent damage. This is often called the depth of discharge (DoD) and is given as a percentage.
As a rule of thumb, lead acid batteries should never be discharged more than 50%, Deep cycle AGM batteries have a maximum discharge of 80%, and lithium batteries can be almost 100% fully discharged.
How To Decide What Type Of Leisure Battery You Need?
Ok, so now that we have a basic understanding of the different variables which affect a campervan battery’s lifetime, we can put it all together and compare the two most recommended types – Lithium and Deep Cycle AGM batteries.
We always recommend the same two types of batteries when we build a campervan electrical system – Deep Cycle AGM and lithium-ion. They work in the same way, but lithium batteries are essentially a newer technology, offering significant benefits but with a heavier price tag. Below are a few things you should know when comparing these battery technologies.
Lithium Batteries (Lifetime)
Lithium batteries typically offer a lifetime of up to 2,000 – 5,000 cycles, with a degradation rate of around 1% per year. On the other hand, AGM batteries have a lifetime of approximately 500 cycles.
Estimating how many battery cycles you’ll use each year is complicated, so we tend to work with a template of rules (as shown below). For example, lithium will offer significant advantages if you have opted for a high-spec electrical system and value reliability and longevity from your batteries.
We recommend lithium batteries if you’re lucky enough to be a full-time van lifer. These will pay for themselves in the long run, but if you’re not convinced, then be sure to check our lifetime price comparison at the bottom of this page.
On the other hand, AGM batteries have a lifetime of around 500 cycles.
If your system is smaller and cheaper and you don’t intend to spend as long off-grid, AGM batteries will likely offer everything you need.
Campervan Battery Capacity & Discharge Depth
AGM vs Lithium Batteries - A few things to keep in mind
It’s worth noting that AGM batteries cannot be discharged to the same extent as lithium batteries. However, your choice of battery capacity can be upscaled to account for this, meaning that lithium and AGM batteries can offer the same total capacity if your system is designed correctly.
For example, a modern lithium battery can be discharged up to 98% of its total capacity, whereas an AGM equivalent can only be discharged 50-80%. You may need 150Ah of deep-cycle AGM battery capacity to achieve the same performance as a 100Ah lithium equivalent.
It’s also worth noting that lithium batteries generally can’t be charged below temperatures of around five °C without causing issues. Doing so can cause permanent damage to your batteries, reducing their capacity. For this reason, if your van life goals include shredding at back-country skiing, we always recommend checking the manufacturer data sheets on any batteries you’re considering.
Lithium batteries don't like freezing temperatures
It’s also worth noting that lithium batteries generally can’t be charged below temperatures of around five °C without causing issues. Doing so can cause permanent damage to your batteries, reducing their capacity. With this in mind, if your van life goals include shredding in the Alps, we always recommend checking the manufacturer data sheets on any campervan leisure batteries you’re considering.
Campervan Leisure Battery Size & Weight
Most van conversions won’t need to worry too much about weight. Still, it is worth noting that AGM batteries will be significantly heavier than the lithium equivalent and will likely take up more space in your van, as you may even need twice as many of them.
This should be considered seriously if your van is smaller or you’re trying to keep weight to a minimum. For example, TN Power’s 100Ah lithium offering weighs 13.1kg, whereas their equivalent AGM battery weighs a whopping 26kg.
How Much Do Campervan Leisure Batteries Cost?
Unfortunately, it’s difficult to estimate the overall lifetime costs of each type of battery due to the different ways we charge and discharge them – our cycles will not always be exactly 50%, 80% or 100%. However, we’ll offer a lifetime cost analysis in a future blog to get deeper into this topic.
The cost of Lithium batteries
So far, lithium batteries have the capacity, size, weight and lifetime all working in their favour. So with that in mind, what’s the downside?
Yep, you guessed it, cost. Lithium batteries will cost more than their AGM counterparts for the same capacity. For example, TN Power’s AGM battery with a usable capacity of 100Ah currently costs £189.99, whereas the lithium equivalent will cost £600.
However, as we’ve discussed, this cost is not the whole story. Lithium batteries will last roughly ten times as many cycles as their AGM counterparts.
Overall, we recommend lithium batteries as long as you can afford the upfront cost – make sure to check the temperature ratings if you intend to spend your winter à Chamonix.
The cost of AGM batteries
With this in mind, AGM batteries may need to be replaced several times during your van ownership, multiplying the cost of the battery several times (not to mention the hours of stress and confusion you could be facing if you have to replace them once they’ve been built into your bench seat).
Which Lithium Battery Is The Best?
We’ve scoured brochures, built the systems and tested a range of campervan leisure batteries so that you don’t have to. Here is what our team at Vunked recommends.
Roamer Batteries get a gold star from us – their batteries have built-in battery monitoring, which is a great feature that others will have to pay a premium for and add complexity to their electrical system to achieve. They even have a new cold-temperature lithium battery, XTREME, which is ideal for those after year-round adventures.
TN Power 100Ah
Victron Energy Battery
For those with some cash to spare and wanting the truly premium option, Victron Energy can’t be beaten on quality. We’re huge fans of Victron Energy because their products are top-notch and reliable. In addition, it’s worth noting that their lithium offering is available as a standalone leisure battery or with all the extras mentioned above.
Which AGM Battery Is The Best?
Deep Cycle AGM Battery
If you’re opting for AGM, we recommend getting a deep-cycle AGM battery, as there’s less to worry about when it comes to over-discharging. For a budget option, we recommend the TN Power 100Ah deep cycle battery, which lets you discharge up to 80% of the battery’s total capacity. This battery is available on its own or with all the required switches, fuses and lugs from our store.
Victron Energy AGM Deep Cycle Battery
For a premium option, once again, we’ve found that nothing beats Victron Energy – which is why we’ve partnered with them to offer you their batteries at a great price. See their 110Ah AGM battery on its own or as part of a package.
- Making sure your batteries are the suitable capacity for your van life ambitions is super important.
- We recommend using our free Campervan Electrics System Builder to help you build the perfect system. See how changing your battery capacity affects your off-grid calculations.
- Once you’ve settled on a battery capacity, the next decision is what technology is right for you (Lithium or AGM).
- If you are conscious of size and weight or have a high-spec electrical system, you should consider lithium batteries. However, you will have to pay a premium for them.
- Those with a smaller or cheaper electrical system or are building their conversion on a tighter budget should consider AGM batteries. The good news is that as long as your batteries have enough capacity to power your appliances (see our off-grid calculator above for help with this). The performance will be very similar once everything is plugged in.
Build Your Own Campervan Electrics System
We hope you found this Campervan Leisure Battery blog helpful in kick-starting your van build.
We have built thousands of systems for adventurers like you, and, as knowledgeable as we are, it soon became apparent that it’s tricky to find the exact match for an electrical system right away. But that’s the beauty of campervan electrics – every van build and owner is unique!
With that in mind, we’ve created a free online tool to help our community to plan out its electrical system in a matter of minutes. So select your off-grid appliances and let us handle the rest.
Keen to try our Campervan Electrics System Builder?