Lithium vs AGM Batteries for Your Campervan: Which Should You Choose?

Choosing the right leisure battery is one of the most important decisions in any campervan build. It powers your lights, your fridge, your phone charging, and — if you've got one — your diesel heater. The two main options are AGM (Absorbent Glass Mat) and lithium (LiFePO4), and the right choice depends on how you use your van.

AGM Batteries: The Budget-Friendly Option

AGM batteries have been the go-to for campervan conversions for years, and for good reason. They're affordable — a decent 100Ah AGM battery costs around £100 to £200. They're widely available, they don't need any special charging equipment, and they're reasonably reliable.

The downsides? AGM batteries are heavy, typically around 25-30kg for a 100Ah unit. You can only safely use about 50% of their capacity before you start damaging the cells, which means a 100Ah battery really only gives you about 50Ah of usable power. They also degrade faster if you regularly discharge them deeply, and they typically last around 3 to 5 years with regular use.

Lithium Batteries: The Premium Choice

Lithium (LiFePO4) batteries are more expensive upfront — a 100Ah lithium battery will cost between £400 and £800. But they come with some serious advantages. They're about half the weight of an equivalent AGM, you can safely use 80-90% of the capacity, and they'll last anywhere from 8 to 15 years depending on use. They also charge faster and maintain a more consistent voltage as they discharge, which means your appliances run better for longer.

The catch is that lithium batteries need a compatible charging system. You'll need a DC-DC charger (sometimes called a battery-to-battery charger) rather than a simple split charge relay, and your solar charge controller needs to have a lithium profile. This adds to the upfront cost but pays for itself over time.

Which One Should You Pick?

If you're on a tight budget and mainly use your van for occasional weekends, an AGM battery will do the job. It's simple to install, cheap to replace, and perfectly adequate for basic lighting, phone charging, and a cool box.

If you use your van regularly, want to run a compressor fridge, need to charge laptops, or plan to spend extended time off-grid, lithium is worth the investment. The longer lifespan, lighter weight, and greater usable capacity make it better value over the life of the battery.

What We Recommend

At Street Vanz Campers, we fit both AGM and lithium systems depending on the customer's needs and budget. Most of our full conversions now go with lithium because the price has come down significantly over the past couple of years, and the benefits are hard to ignore. We'll always talk you through the options and help you decide what makes sense for your build.

Want to chat about your electrical setup? Get in touch with us in Chesterfield — we're happy to advise.