Alternator fault

[Dico]

Started the Elan up yesterday morning for a run to The Peak District. Got around 3 miles from home and noticed the voltmeter gauge was on full, 16 volts. Rather than fry the battery I decided to limp home, keeping the revs as low as possible I managed to keep the gauge down to around 14 volts. Went to start the Elan this morning and the battery was absolutely flat. No life anywhere! I figured the battery had split or something. It hadn't, and I managed to charge it fully. I also played around with the wiring on the back of the alternator to check if anything was loose. All seemed OK. Bit tricky mind as theres such little room there. I had done an oil and filter change earlier in the week and figured I may have disturbed something in that area. Could a broken wire/ loose connector to, say, the regulator cause an increase in volts?
I've just been for a quick run now after the 5 hour charge and the gauge is reading 14 volts again, and even when I give it plenty of revs it sits at 14 volts!? I'll try again tomorrow morning and see if the power drains out again. Odd!

Any thoughts?

[GeoffSmith]

If you disturbed any wiring to the alternator it wouldn't source power. Take it easy as it might be a sign of the alternator regulator pack misbehaving. This is a well known problem when the alternator is used infrequently.



















































































NOT REALLY.

[Dico]

Has anyone ever sourced just the regulator pack do we know, and could it be a diy job to replace? (I may not even need the bleeder now!)

[dapinky]

:lol:

Has anyone ever sourced just the regulator pack do we know, and could it be a diy job to replace? (I may not even need the bleeder now!)

If only some kind-hearted bloke had offered you one from his old alternator yesterday you wouldn't need to ask now

[Dico]

If only some kind-hearted bloke had offered you one from his OLD alternator yesterday you wouldn't need to ask now

This is the reason I would prefer a new one Pinkers. Kind offer tho.

Take it easy as it might be a sign of the alternator regulator pack misbehaving. This is a well known problem

[Andy_J]

Yep, new regulators are available,I managed to source one for the alternator in my red elan, when it started to over charge. However although the regulator had blown, it turned out to be the rotor on my alternator that had failed and blew the regulator.

I will rout around my receipts to see if i can get the references for where i got the regulator from

[Dico]

Cheers Andy.
Rotor? Do you mean the pulley? Mine seized on a few months back but i managed to free it off. Wonder if there's a connection.

[GeoffSmith]

Lots of friction => lots of heat => RPCF

[Andy_J]

Hi Dico

The rotor is the centre part of the alternator that spins, the windings had failed on my alternator. I had an auto electrician who is a friend of a friend rebuild my alternator he diagnosed the rotor fault. I am still trying to hunt down a ner rotor.

I think the new regulator was only about £25

[Dico]

Ah, cheers again.
I think I may need to raid my dads shed again and hunt for my missing alternator (I usualy blame Smithy for my missing parts).

I'm going to take it for a slightly longer run tomorrow and see how it goes. Thats if the battery hasn't drained again.

[Dico]

The battery seems to have remained fully charged overnight

[HJ2]

Then.... regulator it is!
When you've got it out of the car anyway... why not a general overhaul including the regulator, brushes and bearings?

[Andy_J]

Had a rake through all my receipts and I can't find the one for the regulator, but I am 99.9% sure it was one of these I got

http://www.woodauto.com/Component.aspx?Ref=VRG4672A

[Dico]

Then.... regulator it is!
When you've got it out of the car anyway... why not a general overhaul including the regulator, brushes and bearings?

But why did it drain overnight the previous night? Nothing was left switched on. The only thing I've done is fiddle with the wires on the back of the alternator, but to be honest nothing appeared loose. If it was out of the car I would definately have it refurbished, but it isn't.
I'm going for another spin in the car shortly. If all seems OK then I'll just leave well alone. I'll be paranoid on any kind of a lenghth journey.
Thanks for the details Andy.

[GeoffSmith]

Chances are the regulator has discharged the battery because it was too hot. Get it fixed because it will probably happen again.

[Dico]

Cheers Geoffers. I've just been for an hours drive and the gauge didn't move from 13.8 volts . Do you think it could happen again then?

[HJ2]

Could very well be temperature related...

[GeoffSmith]

You may have been lucky but I'd keep an eye on the gauge until you're sure. A few hundred miles (or 3½ years in your case) should be enough.