Battery question


Registered User
Apr 3, 2022
Reaction score
Seems I need a new battery. Was perfect yesterday, but was slow this afternoon when I started it up. It struggled to start again five mins later after getting fuel, understandably since it was running for such a short time. Did a 35-40 min drive, parked up and it was dead when I came back to it some 6 hours later. Everything comes on, lights up and works, but it simply refused to start - didn't even turn over. Called the AA out (as typically, my mini-booster was also dead ‍♂️, and with his jumper pack connected it fired right up just like it always has. He said it was reading 12.3v before he connected his pack and it needs 12.4v to start, hence why it didn't even try. He ruled out the alternator being a problem as it was charging at 14.4-8v while we stood there talking with it running. He did say his machine was saying it was "medium health" but in his experience that basically means it's toast, and even a full mains charge won't get much if any more life out of it. He also didn't try to sell me a battery (I was expecting that after all the above) and said Halfords or GSF would be way cheaper.

Anyway, question is: if the battery is changed like for like (I’m assuming this has an AGM battery in it, as that’s what everywhere suggests) will it need coding/registering to the car or will it just carry on fine? I've heard conflicting reports: some have said just rock the steering lock to lock a couple times and everything resets and will be fine, others have said it needs coding/registering to the car for the stop/start to work properly (which I've disabled with a cheat cable anyway)
Goto Tayna, best battery suppliers.
Any replacement battery being fitted does require coding but your car will continue to work if you don't get it coded although the charging could/may/possibly be affected with not ideal rates applied to the 'new' battery.
Dead as a Dodo this morning, as expected, so a trip to Halfords to get a new one (they only list one battery as the correct one for my car, so I didn't have much of a choice unless I wanted to go to GSF and get a Yuasa that was the same specs, but £40 more and a years warranty less. The Halfords one is a 70ah 760 CCA AGM battery, and the one in the car was a 69ah EFB battery (Varta, so not original). Halfords one went straight in and it started right up, two errors on the dash (hill hold assist and stability, both went away without me doing anything). A friend of mine has an ODB tablet so will see if his can register the new batter to the BMS so it can look after it properly. I'd rather not stick another one in if I can help it, but at least it's got a 5 year warranty (which I'm sure is void if I can't prove it's been registered to the BMS )

Similar threads