Lithium vs AGM Batteries For Off-Grid Adventures

If you’re gearing up for caravanning, camping, or heading bush in a 4WD, you’ll need a reliable battery setup to keep the lights on, the fridge cold, and the beers icy.

But here’s the million-dollar question: should you go lithium or stick with the old faithful AGM batteries?

Both have their place, but the choice really depends on how you travel, what gear you run, and how long you want to stay off the grid.

Let’s break it down in plain English, no boring tech jargon, just the stuff that matters when you’re out in the sticks.

What Are AGM Batteries?

AGM (Absorbent Glass Mat) batteries are basically a type of lead-acid battery where the acid is soaked into glass fibre mats. They’ve been around for ages and are a step up from the old-school flooded lead-acid designs.

• They’re sealed, so you don’t need to worry about leakage.

• They can handle a fair bit of vibration (handy for rough tracks).

• They’re cheaper upfront compared to lithium.

But they’re heavy as a bag of cement, don’t like being fully discharged, and don’t last as long in the Aussie heat.

What Are Lithium Batteries?

When most Aussies talk “lithium” for off-grid power, they mean Lithium Iron Phosphate (LiFePO₄). These are a totally different beast.

• They’re way lighter than AGM (about half the weight).

• You can use nearly the full capacity without killing the battery.

• They charge faster and last heaps longer.

They do cost more upfront, but in the long run, they’ll usually save you coin.

👉 Check out our range of lithium batteries at Outback Safe Track.

Lithium vs AGM - Weight and Size:

Weight is a massive deal when you’re loading up the van. Every kilo counts.

• AGM: A 12V 120Ah AGM can weigh around 30–35kg.

• Lithium: A 12V 120Ah lithium weighs roughly 12–14kg, despite having similar dimensions to the AGM battery.

30-35Kg is manageable when you're dealing with less powerful batteries, however, that weight will creep up considerably as you begin to add more power.

For instance, you may find a 12V 300Ah AGM battery sits around the 70kg mark. On the other hand, a 12V 300Ah Lithium battery may be closer to the 30-35kg range.

Factor in 2 or more batteries and all of sudden you've got another 70+ kilos of unwanted weight!

So if you’re trying to keep under your caravan’s payload limit, lithium frees up weight for more important things – like beer, fishing gear, or that portable aircon.

AGM vs Lithium - How Much Of Your Batteries Capacity Can You Use?

This is where lithium really shines. With AGM, you can only safely use about 50% of the battery’s rated capacity. Go lower, and you’ll seriously shorten its life.

For more information on AGM battery capacity, check out the following article from fullriverbattery.com.

LiFePO4 batteries on the other hand are generally used between 20% and 80% of capacity. Sunonbattery.com have even recommended between 10% and 90% may be feasible. As always, consult your batteries guide to determine the best range.

• AGM: A 120Ah AGM gives you about 60Ah usable.

• Lithium: A 120Ah lithium gives you around 100Ah usable.

That’s nearly double the usable energy from the same “size” battery.

AGM vs Lithium Batteries - How Long Do They Last?

If you’re a weekend warrior who only camps a couple of times a year, cycle life might not matter. But if you’re full-timing or hitting the road for months, it’s a game-changer.

• AGM: About 500–700 cycles at 50% depth of discharge.

• Lithium: Around 3,000–5,000 cycles at 80–90% depth of discharge.

That means lithium can last up to 10 years or more, while AGMs might only last 2–3 years with heavy use. Once again, it all depends on your situation and what will work for you.

AGM vs Lithium Batteries - Charging Speed:

No one wants to waste half a day waiting for batteries to top up. Lithium batteries accept charge much quicker, especially from solar.

• AGM: Slower to recharge, especially after 80% full.

• Lithium: Can take full amps right up until nearly full, meaning faster recovery.

That’s bloody handy if you’ve only got a few hours of sunshine each day!

AGM vs Lithium - Performance in the Aussie Heat:

We all know the Australian heat cooks batteries. High temps shorten battery life, and this is where lithium pulls ahead again.

• AGM: Heat kills them quick. Expect much shorter lifespans up north.

• Lithium: Better tolerance, though extreme temps still aren’t ideal.

If you’re chasing barra in Darwin or crossing the Simpson, lithium is the safer bet.

AGM vs Lithium Cost: Upfront vs Lifetime:

This is the one that trips people up. Lithium costs more upfront, but the maths works out long-term.

• AGM 120Ah: $300–$400.

• Lithium 120Ah: $700–$1,000+.

But remember: lithium lasts more life-cycles and gives you nearly double the usable energy. Over the lifespan, lithium usually ends up cheaper per cycle.

👉 Example: Our iTECH400X PRO 400Ah Lithium might be a bit dearer than a standard old school battery, but it’ll likely outlast several sets of AGMs.

AGM Vs Lithium Maintenance and Practical Use:

• AGM: Maintenance-free, but heavy, bulky, and need careful charging.

• Lithium: Maintenance-free, lighter, smarter (with built-in battery management systems).

Lithium is basically “fit and forget” – perfect if you don’t want to muck around checking voltages every trip.

Which One Should You Choose, AGM or Lithium Battery?

It depends on your situation:

• Go AGM if:

  • You’re on a budget.

  • You only camp a few weekends a year.

  • Weight isn’t an issue.

• Go Lithium if:

  • You travel often or full-time.

  • You rely heavily on 12V gear like fridges, lights, inverters.

  • You want the lightest, longest-lasting setup.

Real-World Example:

Say you’ve got two 120Ah batteries:

• With AGM, you’ll get ~120Ah usable total, and they might last 3 years.

• With Lithium, you’ll get ~200Ah usable total, and they might last 10 years.

That’s 7+ years extra camping without the stress of replacing batteries mid-trip.

Can I Charge My Lithium Battery With Solar?

Lithium pairs beautifully with solar because of the fast charging. You can actually harvest more energy each day because the battery isn’t “dragging its feet” as it gets full.

Check out our solar panel range – from folding blankets to rigid panels – all perfect for keeping lithium batteries topped up.

Also see our guide on how to charge a battery from solar panels.

AGM and Lithium Side-by-Side: Quick Comparison:

AGM Vs Lithium Batteries - Final Thoughts:

When it comes down to lithium batteries vs AGM batteries, lithium is the clear winner for serious off-grid use. Sure, they’re dearer to buy, but you’ll thank yourself when you’re sitting back under the awning with a cold beer and no worries about your fridge dying overnight.

If you’re just getting into camping or don’t go away often, AGMs can still do the job. But if you’re keen on long trips, caravanning full-time, or running a decent solar setup, lithium is the way to go.

And remember: it’s not just about buying a battery. It’s about making sure your adventures run smooth, your gear stays powered, and you can keep chasing sunsets without worrying about a flat battery.

Got questions? Drop us a line — we’ll help you kit out your rig the right way.

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