How do I replace the battery in my car key?+
Most car key fobs use a CR2025 or CR2032 coin cell. Prise the key shell open at the seam with a small flat screwdriver (or slide out the emergency blade and use that), lift out the old battery, drop the new one in with the '+' side facing the same way, then click the shell back together. Test all buttons before driving.
How much does it cost to replace a car key battery?+
A car key battery itself costs £2–£6 from a supermarket or pound shop. Halfords charge £6–£12 fitted. We replace key fob batteries for free during any other locksmith job, or £15 standalone callout if you're already on our route in West London / Slough / Heathrow.
What battery does my car key take?+
The vast majority of UK car keys use one of three coin cells: CR2032 (most common — VW, Audi, BMW, Mercedes, Ford), CR2025 (slimmer fobs — many Vauxhall, Peugeot, Renault), or CR1620 (older Toyota, Nissan, Honda). The battery type is usually printed on the old cell when you open the fob.
Do Halfords replace car key batteries?+
Yes, Halfords replaces most car key fob batteries in-store for around £6–£12 including the battery. It takes 5 minutes. They don't program new keys or fobs — for that you need an auto locksmith or main dealer.
Where can I get my car key battery replaced near me?+
Halfords, Timpson, most independent locksmiths and many supermarkets with a kiosk will swap a key fob battery while you wait. In West London, Slough, Heathrow, Reading, Hayes and surrounding areas we'll do it free as part of any other locksmith job — or call us if your key is dead and you need same-day help.
My remote stopped working after I changed the battery — what now?+
Two common causes: (1) the new battery is in upside-down — flip it so the '+' side matches the diagram inside the fob; (2) the fob has 'forgotten' the car after losing power and needs re-syncing. Try holding lock + unlock together for 5 seconds next to the car, or insert the key in the ignition and turn on/off twice. If still nothing, the fob may need re-pairing — we can do this on your driveway.
How long does a car key fob battery last?+
Typically 2–4 years on a standard remote, 12–24 months on a keyless-go / proximity smart key (because they're always 'listening' for the car). Sticky or unresponsive buttons, having to stand closer to the car than usual, and a low-battery warning on the dash are the three early signs to act on.
Can I damage my car key by changing the battery wrong?+
Very rarely. The two real risks are: cracking the plastic shell with too much force when prising it open, and shorting the battery contacts with a metal tool. Use a plastic spudger or guitar pick if you have one, and never pry against the circuit board. If your key has glued seams (some Renault, Citroën, Peugeot models), book us instead — the shell needs replacing with the battery.
