Am I being stupid? Charging question

[Mne666]

I might be being stupid, feel free to tell me if I am.

Here's what happens, the car runs perfectly well normally but as soon as I put the headlights on it starts to die and then will cut out. I'm getting 13.2v on the battery and I get the same on the back of the alternator, that slowly reduces once there is some load on until it stops at around 12v.

This was happening a few weeks ago so I swapped the alternator with another used one I had which sorted the issue but now exactly the same fault is back.

So, have I just got two dodgy alternators or could it be something else that I have overlooked? I swapped the voltage regs over as I had a brand new one and I tried a different battery off another car which made a slight improvement but not too much.

Thanks

[zd3bx]

Try a re-conditioned/new alternator, which should sort the issue, as the headlights problem definitely points to the alternator.

Most likely both alternators are knackered, so that's why it's better to do it once and do it right.

A new battery would be a good idea as well, if yours is playing up.

[Mne666]

Thought so, thanks very much.

The battery is only a few months old but If it plays up after a new alternator I will have that changed under warranty

I'll have a look at recon/new alternators tonight and get one ordered as I'm sure it's only a matter of time before it packs in completely.

I just didn't know if there was any other component I didn't know about

[Mne666]

Thanks for that , I'll do a test on that in the morning, I'll clean up the connection to the strut too.

If the earth is bad will that show a low voltage reading?

This is a why a forum is so useful

[Mne666]

Cheers mate, makes perfect sense.

I'll report back tomorrow, failing that though would you agree it must be two dodgy alternators?

[Mne666]

I'll check the battery light works too when the ignition is on, I checked it last year but had forgotten about it since.

Can a lead be run direct from both the positive and neutral side or the alternator to the battery to check?

[Mne666]

Sorry for the slow reply, been mad busy.

The battery caption works on the dash, and I tried goomg between the alternator and the battery neutral which made no difference.

It's been stood for a week almost and it was barley making 12v, wanted to cut out each time it idles but drives ok once revving, I didn't even try turning the lights on

[HairyScreech]

That sounds like the brushing pack in the alternator.
These can be changed for a quick fix for about £15.

Get the multi meter out and check the car when idling, then open the throttle a little and check the reading at 1500rpm.
If you find it improves/gets higher then suspect the brushings.

[Mne666]

Hi

If that's the volt regulated I changed that with no improvement