Discharging & Battery light glow

[Hdickins]

Hi all

The battery on my van keeps discharging. There's no overnight current drain (none at all, I took fuse #3 out, to help diagnose it so there's not even a clock) The radio runs off the leisure battery only and I've isolated the leisure battery from the main vehicle battery, so it's not that.

But the battery light glows dimly while I'm driving. And it gets brighter with increasing engine revs... So it seems to be draining while I drive.

What could the problem be, and how can I check?

Thanks!

[Red Westie]

Percentage guess would be that the regulator brushes have worn out.
A new regulator brush pack can be picked up for around a tenner (posted), here is one source:

VEHICLE ELECTRICS, 166 STOCKFIELD ROAD, ACOCKS GREEN, BIRMINGHAM, B27 6AU. TEL : 0121 706 0688 EMAIL: VEHICLEELECTRICS@AOL.COM

Two screws on the back of the alternator...you may need to move the alternator on it's pivot to get to the screws...10 minutes max.

Martin

[Hdickins]

Well, I swapped the regulator/brush-pack - but no dice - same result. But I have got another whole alternator I've just fitted.
BUT... I now have a new question about wiring it back up. The new alternator fits just fine; but there's an extra spade connector - do I need to connect this to anything?

Basically, I've got
1 fat wire attached to the big connection with a 13mm nut.
1 thin wire attached to the small connection with an 8mm nut.
1 thin wire with a female spade connector - and a choice of where to connect it... one labelled "W" and one labelled "+" - so where does the wire go?
(Of course, I ought to have taken more notice when I took the old alternator out. But hindsight is a wonderful thing.)

Thanks again for the help!

[tonytech]

W will be for a rev counter, Diesel vans use a connection from the alternator for the rev counter input.
T

[Hdickins]

It's the "W" apparently, should anyone else have the same problem...

[kevtherev]

did it cure the problem of the red light while driving?

[Hdickins]

did it cure the problem of the red light while driving?

It seems to have fixed it - I'll confirm later - it was only a dull glow and only occurred at relatively high revs.
After a few more days, I also know whether I've cured the discharging; but I'm reasonably confident.

[Hdickins]

Ok. Now I'm more concerned than before...
It's been working fine all week with no red-light glow - not even dimly; until yesterday...

So far this week I've just been driving around town. But yesterday I did a bit of motorway driving - maybe 40 miles, and by the end, the red light was glowing brightly when the revs drop to idle speed.

Have I burnt out my nice new alternator? And if so, how? I'm sure the alternator itself is wired up correctly. I'll go and check the output of the alternator shortly; but are there any other tests I can do?

Thanks.

[kevtherev]

You can test the charging circuit to see if it's grounding, which it might be as you had a discharging issue.

Do you have an Alternator tester in your area, the fella by me checks them out for free.
Was the alternator new or re-conned, did it come with a new regulator?

[Hdickins]

Ok. I can breathe a huge sigh of relief. Mystery solved...

When I fitted the new alternator, I made sure to tighten the sliding-bolt on the side of the alternator to make sure the belt was tight.
But I managed to leave the hinge-side bolt fairly loose! So, as you can imagine, this bolt has now worked loose and gone missing, causing the alternator to slip down and it was only spinning properly at high revs.

So, now, I simply need to find a replacement bolt for the left-hand "hinge" side. I don't have such a bolt at the moment - so I'm using a big screwdriver threaded through as a hinge-pin.

[kevtherev]

Ah posted in a panic.. before investigation.

[Hdickins]

Exactly. Please accept my apologies...

At least it all makes sense now.