Hmm Battery not charging, idea's?

[M3CHA-MONK3Y]

Hi

Driving to my girlfriend's house last night, I realised my battery light was still on and my ammeter was showing 11 volts, flickering just above the red. Now usually when I start the car the battery light stays on till I top 2'000 rpm then switches out and doesn't come back on again even at idle. This time it stayed on. Got to the g/f's house, checked the belt, it had the right amount of play, the alternator terminals hadn't rusted off and seem like a good connection.

I put it on charge through the night and ran a voltmeter across the alternator terminals and it's showing 10 volts on idle, which doesn't increase with revs.

Now I always believed that an alternator either worked or didn't, so if that train of thought is correct could it be something like belt slippage or some strange TVR thing i've not heard of?

Cheers

[Le TVR]

The alternator is connected directly to the battery so you will see the battery voltage whether the alternator is working or not.

So it does sound like the alternator has gone awol.

[Barkychoc]

You should see in the region of 14 volts when the alternator is working - so as above looks like the alternator has given up.

Just another point - don't ever run the alternator with the big output wire disconnected (or disconnect the battery with the engine running) otherwise it can be toast.

Edited by Barkychoc on Tuesday 25th November 13:31

[GreenV8S]

The battery dropping to 10 volts despite being on charge overnight is another bad sign. I suggest you disconnect the battery and see what voltage it's reading - it sounds as if it may have dropped a cell. That's something that can easily happen if the battery has been deep discharged. It may be that you need to replace the battery as well as getting the alternator fixed.

[M3CHA-MONK3Y]

Cheers guys,

I've just been out for a blast in it at lunch and its started to charge again. Strange. Although just because its working again doesnt mean its fixed so this weekend i'll prob whip the alternator out and have it tested by a bloke I know. Cheers for your comments, Can only thing maybe the belt was slipping or the alternator was damp, who knows.

Thanks again Ad

[Gerald-TVR]

Adrian apologies if i've asked before but where in Worcestershire, I live in droitwich!!

[M3CHA-MONK3Y]

This has gone from the sublime to the ridiculous. Now instead of not charging, the alternator is now over-charging at over 15 volts, higher than my ammeter gauge can read!
Once again, any idea's? Once you reach 3000 rpm the alternator is belting out 15 volts. I thought it could be my ammeter is faulty but under rev's my main lights become insanely bright and my CD trips out (probably to protect form melting).
It's got to be a dead alternator hasn't it?

Cheers Ad (I live in Redditch)

[Gerald-TVR]

There an Auto Electrician based in Studley who I have used and he did a good job in installing a fan switch and removing the dreaded yellow connector. His Brother (or in Law perhaps) specialises in alternators might be worth while getting him to check you car out.

The electrician is

C E Williams
30A Nod Hill
Studley B80 7RG
01527 853463

Must meet up for a pint some time

Norman

[tvrgit]

M3CHA-MONK3Y said:

This has gone from the sublime to the ridiculous. Now instead of not charging, the alternator is now over-charging at over 15 volts, higher than my ammeter gauge can read!
Once again, any idea's? Once you reach 3000 rpm the alternator is belting out 15 volts. I thought it could be my ammeter is faulty but under rev's my main lights become insanely bright and my CD trips out (probably to protect form melting).
It's got to be a dead alternator hasn't it?

Diode Rectifier / regulator pack (it's a little part on the back of the alternator). Might get away with just changing the pack, much cheaper than new alternator.

[jimed]

You could take off the rectifier pack as mentioned above and get that checked - just undo the 2 screws and it slides out. It also has the carbon brushes attached so you can check they are OK as well. I enquired about a replacement pack some time ago and it wasn't too much.
Jim
PS Another thought, though may not be relevant, is the earth from the alternator as per Peter's (Green V8S) recent post.

[M3CHA-MONK3Y]

Gerald-TVR said:

There an Auto Electrician based in Studley who I have used and he did a good job in installing a fan switch and removing the dreaded yellow connector. His Brother (or in Law perhaps) specialises in alternators might be worth while getting him to check you car out.

The electrician is

C E Williams
30A Nod Hill
Studley B80 7RG
01527 853463

Must meet up for a pint some time

Norman

I've actually used him a few times, sorted out my dynamo when I had the Sprite, knows alot and well priced.
Definetly meet up for a pint, name the time and place, i'm free most weekends.

Cheers Ad

[M3CHA-MONK3Y]

jimed said:

You could take off the rectifier pack as mentioned above and get that checked - just undo the 2 screws and it slides out. It also has the carbon brushes attached so you can check they are OK as well. I enquired about a replacement pack some time ago and it wasn't too much.
Jim
PS Another thought, though may not be relevant, is the earth from the alternator as per Peter's (Green V8S) recent post.

I've got a mate who's works at Gaydon Motor Museum and that was his guess too. I'll prob nip down to see the bloke GeraldTVR suggested. Thanks Jimed and TVRGit.

Reassuring to know theres a place I can go if a have a problem, cheers again.