Best 100Ah Lithium Battery for a Caravan in Australia

The short answer

For most caravans and camper trailers, a good 100Ah LiFePO4 (lithium iron phosphate) battery is the best all-round upgrade you can make. It gives you roughly twice the usable power of a 100Ah AGM at less than half the weight, and it will usually outlast several lead-acid batteries.

The "best" one is the one that fits your space, handles your loads and is backed by a warranty you can actually use in Australia. This guide shows you how to judge that for yourself.

Why 100Ah lithium is the sweet spot

A 100Ah LiFePO4 battery lets you use close to its full rated capacity. With an AGM you should only use about half if you want it to last, so a 100Ah AGM really behaves like a 50Ah battery.

It also weighs around 10 to 12kg against roughly 27 to 30kg for a 100Ah AGM. On a caravan, every kilo you save comes off your payload and ball weight.

Lithium holds a steady voltage until it's nearly flat, so your fridge and lights keep working properly right through the discharge instead of struggling as the voltage sags.

What to look for

A BMS rated for your loads. The battery management system protects the cells. Check its continuous discharge rating (100A is common) covers everything you might run at once, including an inverter.
Low-temperature charge protection or self-heating. LiFePO4 must not be charged below about 0°C. If you camp in the high country or inland in winter, choose a battery that blocks or heats before charging.
Bluetooth monitoring. Being able to see state of charge and cell balance on your phone makes it much easier to manage power at camp.
Size, terminals and mounting. Measure your battery box or mounting spot, including room for cables and lugs, before you buy.
Charge current rating. Check the maximum charge current suits your DC-DC charger and solar controller.
Warranty and local support. A long warranty means little if the seller can't be reached. Look for an Australian address and clear claim process.

How long will 100Ah last?

Work it out from your own gear. A typical 12V compressor fridge averages about 1 to 2A across a day, depending on its size, the weather and how often it's opened. That's roughly 24 to 48Ah a day.

Add LED lights, a water pump, phone and laptop charging and many couples land somewhere around 40 to 70Ah a day. So a 100Ah lithium battery covers a night or two on its own, and much longer when it's being topped up.

Pair it with charging

A battery only stores power; you still need to put it back. Most caravanners use a DC-DC charger while towing and solar at camp. As a rough guide, 200W of solar can put back around 40 to 60Ah on a clear day, less in winter or in partial shade.

Make sure every charger connected to the battery is set to a lithium (LiFePO4) profile. Our DC-DC charger size guide covers matching the charger to the battery.

Common mistakes

Buying on price alone with no checkable warranty.
Leaving an old charger or solar regulator on an AGM setting.
Using thin cable from the car to the van, so the battery never fully charges.
Mounting the battery loose. It needs a proper tie-down that will hold in a sudden stop.

Quick FAQ

Can I put lithium in my existing battery box? Usually, if it fits and the box's outlets and fuses are rated for the current. Check the charger built into the box (if any) has a lithium setting.

Is one 200Ah better than two 100Ah? One battery is simpler. Two smaller ones can be easier to fit and lift. Either works if they're installed and fused properly.

Do I need a battery monitor? Bluetooth batteries often have one built in. Otherwise, a shunt-based monitor is the most accurate way to see what's going in and out.