As Unlucky Alf from the Fast Show might have said "Oh bug*er" - the battery light came on again. I thought that this may happen since I have been regularly checking the battery voltage and it's never gone above 12.5v with the connector connected. My theory is that the alternator saw the battery voltage at 13v and informed the ecu that all is well, and did not need to charge it.

The alternator's smart charge circuit is clearly incapable of charging the battery smartly, so when the voltage fell below 11.8v the light came on - I know this because I fitted a jury rigged voltmeter to the cigarette lighter so that I could monitor it.

I have unplugged and will wait until the battery gets to near 13v before reconnecting it - I may fit a switch to do this from inside the car, who knows...

Has anyone replaced the alternator on a 2006 Ka, and is it do-able in a simple way or do you really have to remove the headlight and fan shroud etc pls? I only ask as replacing the lower wishbones looked a cinch in the manual but turned out to be a lot harder than advertised! Thanks.

Everything is difficult and awkward on a Ka.  I'd much rather work on something Focus or Golf sized.

1 hour ago, TomsFocus said:

Everything is difficult and awkward on a Ka.  I'd much rather work on something Focus or Golf sized.

I agree. My first car was a Ford Cortina Mk2 1300 Deluxe and you could almost walk about in the engine bay on that!

I'm still running with the smart charge plug disconnected and there are no ill effects apart from the battery light staying on - and it recently passed the MOT.

I notice that I can buy a replacement regulator for my alternator which seems an easy fix if if can be done in-situ.

Has anyone ever replaced a regulator on an alternator like this and can it be done whilst the alternator is in-situ please?

35 minutes ago, Oriskany said:

Has anyone ever replaced a regulator on an alternator like this and can it be done whilst the alternator is in-situ please?

To quote my learnard friend above:

On 7/12/2023 at 11:00 AM, TomsFocus said:

Everything is difficult and awkward on a Ka.

At the very least you are going to have to remove the alternator from the engine

Well - for better or worse I've ordered a new regulator - let's see how I get on. I could have ordered a second-hand alternator but who knows what shape that'd be in?

Did you manage to change the regulator, and did it make any difference.

On 10/2/2023 at 11:28 PM, WilB0 said:

Did you manage to change the regulator, and did it make any difference.

I haven’t yet as the battery is charging and holding charge just fine. The charging voltage is steady at 13.8v - the same as my Suzuki Alto which is fitted with a dumb alternator. I would like to try in the near future just to get the battery light to go out and regain my smart charge features but doing anything under the bonnet is just so difficult isn’t it? We’ll see but I will report any success.