How to tell if your car battery is flat (or about to die)

How do I know if my battery is flat?

Signs your car battery is flat (or about to die) include:

• Your engine cranks but won’t start
• Nothing happens when you turn the key
• Headlights or electrics are dim or unresponsive
• Your stop-start function has stopped working
• You’ve needed a jump start recently
• You notice corrosion, swelling, or a rotten egg smell
• Your battery is over 3 years old

If you’re stuck with a flat battery, call Marshall Batteries on 1300 MARSHALL / 1300 627 742 for fast roadside help — no membership needed.

If you know you need a replacement battery soon, you can use our battery finder tool to get a quote from your nearest car battery store.

Engine cranks slowly — or not at all

If your car tries to start but struggles or fails completely, your battery is likely flat or nearly dead.

The battery powers the starter motor, which cranks the engine. A slow crank or complete silence usually means it’s time for a jump start or a new battery.

Marshall Batteries offers quick roadside jump-starts and battery replacements across Australia — even in many regional locations.

Turn the key and nothing happens

No dashboard lights, no sounds, no clicks? That’s a classic sign of a flat battery — especially if your headlights or interior lights also aren’t working.

If your lights do come on but the car won’t start, the issue might be your starter motor or alternator.

Got a stop-start vehicle?

If your car shuts off at red lights to save fuel, it has a start-stop system — and standard batteries won’t cut it.

Start-stop car systems need EFB or AGM batteries, which are built to handle frequent starts.

If your stop-start feature has suddenly stopped working, or the car is sluggish to restart at lights, your battery could be on the way out — even if the rest of the car seems fine.

Marshall Batteries carries the correct battery types and can test and expertly fit them roadside.

Alternatively, you can check out our start-stop battery range if you know what you’re looking for, or use our battery finder tool to get a quote from your nearest store.

Lights flicker or electrics glitch out

Modern cars rely on battery power to run everything from infotainment to power windows. If these systems are dim, slow, or acting strangely, your battery may not be holding charge.

You’ve had to jump-start it (again)

you’ve jump-started your car more than once in the last week, your battery is no longer reliable — even if it’s relatively new.

Frequent jump starts will strain the battery and usually signal a deeper problem. Drop into your nearest Marshall Battery Shop for a FREE Car Battery test or simply Holler for a Marshall on 1300 627 742.

You spot physical warning signs

Pop the hood and check your battery. These are red flags:

• Bloated/swollen case (due to heat or internal damage)
• Corrosion around terminals (white, blue, or green powder)
• Battery fluid leaks or a rotten egg smell (sulfuric acid)
• Loose or corroded cables

If you see any of these, it’s time for a battery replacement.

Your car goes flat after sitting for a day or two

If your car starts fine after regular use but fails after sitting idle, something might be draining the battery — like a faulty electrical component or an old alarm system. You’ll need a battery specialist to run a test.

Your battery is more than 3 years old

Car batteries typically last 3–5 years in Australian conditions.

Extreme heat, short trips, or long periods without use can shorten battery life. If yours is getting on in age, it’s smart to replace it before it fails or at the very least, get a Battery Test.

Reminder for start-stop cars

If your car has a start-stop system, be extra mindful:

• These batteries cycle far more often than regular ones
• They require EFB or AGM batteries, not standard flooded ones
• A failing battery might only show signs through the stop-start feature — not through obvious cranking issues

Never install a regular battery in a start-stop car. It won’t handle the load and could damage your electrical systems.

Marshall Batteries can test and replace your battery with the correct oneright across Australia.

Need help now? HOLLER for a Marshall

Marshall Batteries offers 24/7 roadside battery service with:

• No membership required
• Australia-wide coverage, including most regional areas
• Battery testing, jump starts, and replacements on the spot
• Up to 42 months nationwide extended warranty on Marshall Batteries

Call us on 1300 MARSHALL / 1300 627 742 or find your new battery using our battery finder tool.

Flat battery FAQs