Can I change my car battery myself, or should a garage do it?
It depends on the age of your car, and that's the honest answer. A garage charges £120-250 to supply and fit a battery that costs £70-150 to buy, so DIY can save you £50-100. On an older car with a simple engine bay, go for it. On most cars built after about 2015, especially anything with stop-start, the new battery needs to be electronically registered to the car, and that tips the job back towards the garage.
Garage price vs doing it yourself
| Garage, supplied and fitted | Battery only | You save |
|---|---|---|
| £120-250 | £70-150 | £50-100 |
The spread in both columns is mostly battery type. A basic battery for an older petrol hatchback sits at the bottom. Stop-start cars need a tougher (and dearer) EFB or AGM battery, which is most of why their fitted price climbs towards £250. Main dealers can want £300 or more for the same job, which is one of the clearest examples of the dealer vs independent price gap there is.
How hard is it really?
Physically, it's a 10mm spanner and ten minutes. Disconnect the negative (black) terminal first, then the positive, undo the clamp holding the battery down, and lift it out. Fitting is the reverse: positive on first, negative last. The lifting is the bit people underestimate. A car battery weighs 15-25kg, it's an awkward dead lump, and it's full of acid, so keep it upright and keep it off your foot.
On an older car, that really is the whole job. If yours is pre-2010 with the battery sitting in plain view under the bonnet, the battery itself is £70-150 online, matched by your registration, and you'll have it swapped before the kettle's boiled.
Modern cars are a different story. Disconnecting power wipes settings: the radio may demand a security code you might not have, one-touch windows need re-teaching, and some automatic gearboxes take a while to relearn their shift behaviour. None of that is fatal, but it catches people out.
When you should NOT DIY this
Be honest with yourself on these four. First, stop-start cars. The car's battery management system needs telling a new battery has been fitted, a two-minute job with diagnostic kit the garage has and you probably don't. Skip the registration and the car keeps charging as if the old, tired battery were still in, which cooks the new one early and can make the stop-start refuse to work. Second, anywhere the battery is buried: in the boot floor, under a seat, or under trays of plastic trim. Third, hybrids and electric cars. The 12V battery itself is normal, but it often lives near high-voltage kit, so leave it alone unless you know exactly what you're looking at. Fourth, if you don't have your radio code and the car's old enough to need one. Find the code first, then decide.
Fitting the wrong type matters too. Put a standard battery in a stop-start car because it was £40 cheaper and it'll be dead within a couple of years. Match EFB with EFB, AGM with AGM.
If you'd rather a garage do it
A fair fitted price is £120-250 including the battery, the registration to the car, and disposal of the old one. Battery specialists and mobile fitters often fit free when you buy the battery from them, which quietly makes them the best value route for a modern car. Where it goes wrong is the £300+ dealer quote, or a garage charging a separate £40-60 "coding fee" on top of an already full price. If a quote smells off, check it against our fair prices with the reg checker before you say yes.
Common questions
Does a new car battery really need to be registered or coded?
On most stop-start cars from around 2015 on, yes. The battery management system adjusts charging as a battery ages, so it needs telling it has a fresh one. Skip it and the new battery gets overworked and dies early. Older cars without stop-start need nothing coding at all.
Will I lose my radio code or settings when I swap the battery?
Possibly. Older head units can demand a security code once power is cut, and things like one-touch windows and clock settings usually need resetting. Garages often plug in a memory saver to avoid this. Find your radio code before you disconnect anything, not after.
How long does a car battery last?
Four to seven years is typical in the UK. Short journeys, stop-start systems and cold winters all shorten that. If the engine cranks slowly on a cold morning or the battery light flickers, get it tested. Most motor factors and battery fitters will test it free.
Can I fit a cheaper standard battery in a stop-start car?
You can physically, but don't. Stop-start cars need an EFB or AGM battery built to handle constant restarting. A standard battery in that role will be flat or failing within a couple of years, and you'll have spent the saving twice over. Match the type that came out.
Is it dangerous to change a car battery?
Not if you follow one rule: negative off first, negative on last. That stops your spanner shorting the live terminal to the bodywork. Batteries also contain acid and can give off flammable gas, so no smoking, no naked flames, and lift with your knees. It weighs more than you think.