Charging issue

[MikeB]

Folks

Further on from what looked like a lazy ignition/charging light, I had a flat battery yesterday, so charged the battery up and let it sit overnight, it showed 12.5 v when I went out to it today.

It started the car, the ignition light went out but even when running at 3000rpm the battery was still at 12.5 v. So what do you think, regulator or alternator?

Signed on for a PCI trackday on Saturday, so keen to get it sorted, as will have to get the bits ordered tomorrow morning in order to make it.

[jwhillracer]

Could be either, Mike. It would be worth getting a good auto electrician to check it out.
I presume that you have checked out the obvious loose or corroded connections.

Cheers,
JW

[MikeB]

Jonathan

Yes have checked the connections to the alternator and the regulator. it's the fact the light goes out when it starts that is out of my experience, haven't seen that before.

[Sam]

Surely if the battery is only showing 12.5v after being on charge overnight you need a new battery?

It ought to be well over 13v, nearer 14v.

[MikeB]

Sam, think you are being optimistic there, it will be those sort of voltages when being charged by the alternator, which it isn’t at the moment, unfortunately

[anglophone1]

When mine went early this year it was alternator- got one of Jonny Harts high power ones- with regulator built in..................