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JDG

Aug 31, 2025
8
1
The voltage of the12v battery on my SEAT Leon ehybid 2025 usually reads 11.7v to 11.9v. I've manually charged it and also done an 8 hour journey and although the battery then shows 12.3v, by the next day it has gone back to under 12volts. I also have difficulty in charging the traction battery. When I plug in, it flashes white for a minute or so, then turns red. I can get it to charge if I turn on the ignition before plugging it in, it then charges OK (and I switch off the ignition). It also charges OK immediately after a long drive.

So I think it is a duff 12v battery. As the car was new/registered in May25 and I got it in August, the battery is pretty new. I doubt I can get it replaced under the warranty (I'm hundreds of miles from the dealer I bought it from). But when I get round to finding somewhere that can update the software (to get Schedule Charging) I'll ask them to check out the traction battery charge problem at the same time.

So assuming I will have to fit a new 12v battery fairly soon, does anyone have any recommendations for a particular battery? Is AGP a better choice than EFB for the Leon ehybid /PHEVs? I think my DIY skills are up to it. I've just bought a OBDeleven to start findng out about the car, and so I can hopefully program for a different battery, if needed.