Choosing batteries for your camper van is a huge decision. Your power bank is at the heart of your system. Running out of power is something you never want to experience. In this post we’ll go over the two main battery chemistries found in the van world and introduce a third lesser known one to give you the information you need to choose the system that’s right for you. 

Here’s also a video with the same information covered if you don’t like reading. 

 

When talking about the different battery options for camper vans we’ll be looking at 3 aspects. Discharge floor, discharge profile, charge resistance, charge cycling.

• Discharge floor - how far a battery can be discharged before damage occurs.
  
• Discharge profile - how well a battery maintains a usable voltage as it is discharged.
  
• Charge resistance - how readily a battery receives power when charging. 

Now that you have the basics down we’ll dive into the two big players in the off-grid electrical storage game. AGM and lithium.

AGM

AGM batteries have been the standard energy storage method for solar systems for quite some time. They are economical, reliable and get the job done. They are the cheapest options for energy storage but there are some drawbacks.

The biggest one being that their discharge floor is quite high. AGM batteries cannot be discharged below 50% of their total capacity. If they are discharged past 50% they can become damaged and after a certain point they can not be recharged. This means that if you have a 100AH battery, only 50AH of it is usable. This can lead to large battery banks needed to serve your needs.

The second issue with AGM batteries is their discharge profile. As an AGM battery is discharged the voltage drops constantly. Eventually, the voltage will hit a point where the appliances in your system stop getting the voltage they need to operate and therefore, stop working.

The final drawback lies with their charge resistance. The lead-acid chemistry of AGM batteries means that the internal resistance when receiving charge current is quite high. This means that they need more power to charge quickly.

All of this is not to say that AGM batteries won’t work. They are tried and true technology that can certainly serve your needs.

Here’s a quick recap of the pros and cons of AGM batteries.

AGM 

• Pros
• Budget friendly
• Cons
• Voltage drops as battery discharges
• Higher resistance resulting in slower charge time
• Easily damaged 

Lithium

Lithium has really come into its own over the last 10 years or so. They are now the battery of choice for nearly everything that requires mobile power. From smartphones to electric cars they are everywhere. This is for good reason too.

Lithium batteries have a fantastic discharge floor. They can be drained to near zero without risk of damage. This gives you more usable power per battery and can help save space.

Another pro of lithium is that they maintain consistent voltage for longer as they are discharged. Their discharge graph is uniform until about the last 10% which allows your appliances to get the proper voltage for longer.

Finally, lithium batteries have a low internal resistance which means they can be charged very quickly. Since you don’t have to push the power in as hard as with other battery chemistries this means that you can have a smaller solar set up that is still very effective at charging.

While lithium batteries have many benefits, they also have some major drawbacks. First, they are very expensive. Typically you will pay 2-3x more for a lithium battery compared to AGM. They are the most expensive option for camper van energy storage.

The second drawback is that they are sensitive to cold temperatures. Charging them at or below freezing can cause damage and ruin them to the point of rendering them unusable. Cold temperatures also significantly impact their capacity. They may lose as much as 50% of their capacity in colder temperatures.

Battery manufacturers have come up with a solution to help address the temperature problem. There are options for batteries that have internal heating elements to keep them above freezing to avoid low temperature damage.

Lithium batteries are definitely considered the gold standard for energy storage at this time but it’s important to take into account their limitations. Especially if you will be using your van in colder climates. We definitely recommend getting ones with internal heating.

Here’s a quick recap of the pros and cons of lithium batteries.

Lithium 

• Pros
• Can discharge to near 0
• Voltage does not drop off as battery discharges until very end
• Low resistance allows for faster charging
• Cons
• Can be damaged when operating at low temperatures  
• Very expensive

Silicon Dioxide

And now on to our third, lesser known option. Silicon dioxide. This battery technology comes from our friends up in Canada and merges some of the benefits of AGM and lithium to provide a different solution to energy storage.

Silicon dioxide batteries are very similar to AGM batteries in construction but they use silicon dioxide instead of sulfuric acid as the electrolyte solution. This change allows for the batteries to be discharged to near zero and also permits them to operate down to -50F with little risk of damage.

Finally, silicon dioxide batteries are more expensive than AGM but cheaper than lithium. They provide a nice middle ground when it comes to price.

Here’s a quick recap of the pros and cons of Silicon Dioxide batteries.

Silicon Dioxide

• Pros
• Can discharge to near 0
• Middle of the road pricing
• Can be charged and discharged in extreme temps down to -50F
• Cons
• Voltage drops as battery discharges
• Higher resistance than lithium resulting in slower charge time

There you have it. AGM, lithium and silicon dioxide are our batteries of choice when it comes to building our off-grid van power systems.

All 3 of the battery types discussed above will absolutely work for powering your camper van. What it really comes down to is the environment you’ll be using them in and what you’re willing to spend up front.