Mobile Car Battery Replacement, 24 Hours a Day

A car battery rarely fails at a convenient moment. Roadside Assistance Group replaces car batteries where the car is: at home, at work, in a car park or at the roadside, 24 hours a day. Call 020 8088 4032, give us the reg number and the model, and we'll explain what we can do and what it will cost before anyone heads out. We aim to reach you within 45 minutes in London.

Signs your battery is on its way out

Batteries usually give warnings first. Look out for:

• Slow cranking. The engine turns over sluggishly, especially first thing on a cold morning, then catches at the last moment.
• A clicking sound and no start. A rapid click when you turn the key or press the start button usually means there isn't enough power to turn the starter motor.
• Dim lights and weak electrics. Headlights that brighten when you rev, a dashboard that flickers, or central locking that hesitates.
• The battery warning light. It can point to the battery itself or to the charging system, so it's worth getting checked either way.
• Repeated jump starts. If the engine fires up after a jump yet is dead again a day or two later, the battery may no longer hold its charge.
• Start-stop stops working. Many cars switch the start-stop system off when battery charge is low.
• Visible damage. A swollen or cracked case, leaking fluid, heavy corrosion on the terminals or a rotten-egg smell. Don't try to jump start a battery in that condition.

Our guide to the signs your car battery is dying goes into more detail.

Is it really the battery?

Not every flat battery needs replacing. If a healthy battery has simply been drained, say by an interior light or weeks parked without use, a jump start (from £70) will get you going. Equally, a faulty alternator will drain even a brand-new battery, so fitting a new one without checking the charging system can waste your money. Our articles on flat battery or alternator problems and whether you need a jump start or a new battery help you work out which it is.

So we ask questions on the phone first: the symptoms, the battery's age if you know it, and whether it has happened before. If it sounds like a flat but healthy battery, we'll say so.

What a mobile battery replacement involves

On most cars this is straightforward, but modern vehicles add a few steps.

1. Testing. The battery and the charging system are checked, so the fault is confirmed before anything is replaced.
2. The right battery. Batteries differ in size, terminal layout and capacity. Cars with start-stop usually need an AGM or EFB battery, and fitting a standard one can cause problems. Our start-stop battery replacement article explains why.
3. Removal and fitting. The old battery is disconnected and removed, the tray and terminals are cleaned, and the new battery is fitted and secured. The technician takes the old battery away, so you aren't left to dispose of it.
4. Settings and checks. Some cars need the new battery registered with the car's computer, and some lose radio codes, window settings or clock settings when the power is disconnected. Tell us your make and model so we know what to expect. Finally, the car is started and the charging voltage is checked.

Hybrids and electric cars also carry a small 12V battery of their own that runs the electrics and can go flat like any other. Call us to check whether we can replace it on your model.

What happens when you call

• You call 020 8088 4032, day or night. We ask where you are, which car it is (reg and model) and what it's doing.
• You get a price for your car before anyone heads out, so there are no surprises.
• We come to you. Home, workplace, supermarket car park or roadside. If you're in a multi-storey or basement car park, tell us the level and any height barrier.
• The job is done where the car is, and you can drive away once it's finished.

If you've stopped on the road

If the battery gave up on the road rather than at home, put your own safety before the car. Hazards on, everyone out through the doors furthest from passing traffic when that's safe, and wait well clear of moving vehicles, behind any crash barrier on a motorway. Anyone who can't leave the car safely should keep belted in and dial 999.

When a new battery isn't the answer

Occasionally a fresh battery doesn't solve it, because the fault lies with the starter, the alternator, the wiring or something else. If the car can't be fixed where it is, we can arrange car recovery, priced from £120, to take it home or to a garage you trust.

Old batteries

When we replace your battery, our technician takes the old one away. Car batteries are hazardous waste and, by law, mustn't go in household bins, so any other old battery you have should go to a recycling centre or a garage that accepts them.