If you've ever Googled "what battery does my car need" you've probably ended up more confused than when you started. AGM, EFB, calcium, gel, lithium, deep-cycle, hybrid — the marketing is deliberately overlapping. Here's what each actually is, with the honest tradeoffs.
Standard flooded (calcium) — the base case
What 90% of cars built before 2015 came with. Lead plates, liquid sulphuric acid electrolyte sloshing around inside, with calcium added to the lead alloy to reduce water loss. Reliable, cheap, well-understood. Lifespan in Perth: 3-4 years.
- Best for: older cars, basic 4WDs without Stop-Start, motorcycles, small petrol cars
- Cost: $$ (the cheapest of the lead-acid chemistries)
- Not for: anything with Stop-Start, regenerative braking, or heavy electronics
EFB (Enhanced Flooded Battery)
A heavy-duty version of the standard flooded battery, designed specifically for the introduction of Stop-Start systems. Thicker plates, better grid alloy, and a polyester scrim wrap that stops active material from shedding off the plates during repeated deep cycling. About 2× the cycle life of a standard battery.
- Best for: mid-range cars with basic Stop-Start (most Japanese and Korean cars 2015-2022)
- Cost: $$$ (around 30-50% more than standard flooded)
- Sweet spot for: Mazda CX-5, Hyundai Tucson, Toyota Corolla, Kia Sportage
AGM (Absorbed Glass Mat)
The electrolyte is absorbed into a fibreglass mat rather than sloshing around. This makes the battery sealed, spill-proof, vibration-resistant, deeply cyclable (~3× EFB lifespan), and able to handle the high-current bursts of regenerative braking. The premium choice — and required by most European cars and any vehicle with serious electrical demands.
- Best for: European cars, luxury cars, cars with regenerative braking, deep-cycle auxiliary use, marine, caravan
- Cost: $$$$ (typically 1.8-2.5× standard flooded)
- Required for: BMW, Mercedes, Audi, Volvo, late-model VW with Stop-Start
Gel batteries
Like AGM but with the electrolyte set in a silica gel instead of a fibreglass mat. Excellent deep-cycle performance, but a slower charge rate makes them poorly matched to modern car alternators. These days they're mostly used in mobility scooters, solar setups, and specific marine applications. Rarely fitted to cars.
Lithium (LiFePO4) batteries
Half the weight, 5-10× the cycle life, almost no self-discharge. Brilliant — but for cars, the picture is mixed. Most cars are not designed for lithium-spec voltage and charging profiles, and a lithium crank battery in a regular car can confuse the alternator and the body computer. Where lithium shines: auxiliary batteries in 4WDs, caravans, and marine.
- Best for: deep-cycle auxiliary use, racing, weight-critical builds
- Cost: $$$$$ (4-6× lead-acid)
- Not yet for: most factory crank battery applications
Quick comparison
| Chemistry | Cycle life | Heat tolerance | Perth lifespan | Cost |
|---|---|---|---|---|
| Standard flooded | Low | Average | 3-4 years | $$ |
| EFB | Medium | Good | 4-5 years | $$$ |
| AGM | High | Very good | 4-6 years | $$$$ |
| Gel | High | Average | 4-6 years | $$$$ |
| Lithium (LiFePO4) | Very high | Excellent | 8-12 years | $$$$$ |
The simple rule
Whatever your car came with from the factory, fit the same type or better. Never downgrade. Standard flooded → EFB or AGM is fine (and often a great upgrade for heat tolerance). EFB → AGM is fine. AGM → anything less is a guarantee of premature failure and possible dash warnings.
Easiest path
Send us your rego — we'll look up the factory spec and tell you exactly which chemistry, size, and brand to fit, with on-site pricing. No callout fee, no obligation.
Need help choosing?
We carry standard flooded, EFB, AGM and deep-cycle AGM on the van for every callout. If you're not sure what you need, we'll test what you've got, look up your fitment, and recommend the right chemistry for the next 5 years — not just the cheapest one we can sell you.
Frequently asked
Is AGM worth the extra money for an older car?+
If your car is older and doesn't have Stop-Start, AGM is overkill in most cases. The exception is if you live somewhere very hot and want maximum lifespan — AGM handles Perth heat noticeably better than standard flooded.
Can I fit AGM to a car that came with standard flooded?+
Yes, AGM is a valid upgrade path. The alternator and electrical system don't need any changes for the cars we see. It's only the other direction (downgrading from AGM) that causes problems.
What's the difference between AGM and 'deep-cycle' AGM?+
Crank AGM is optimised to deliver short high-current bursts to start the engine. Deep-cycle AGM is built to discharge slowly over hours (running a fridge, lights, etc.) and recharge fully. Don't use deep-cycle as a crank battery or vice versa.
How do I know what's in my car right now?+
Look at the battery label — AGM and EFB are clearly marked. If it just says 'maintenance-free' with a model code, it's standard calcium flooded.
Common service areas for this guide