ignition light comes on when going uphill

[killerme]

vw t25 1600TD: ignition light slowly and dimly comes on when going uphill or when accelerating. Goes off completely otherwise. I guess this could be alternator drive belt tightening, new alternator (or brushes?? Do alternators have brushes) or something else like spark plugs, cable etc

Can anyone suggest the right path to find the solution?

thanks for the help

[R0B]

They have a regulator like this.Worth removing yours to check the condition of the brushes..https://www.brickwerks.co.uk/voltage-re ... 3-all.html" onclick="window.open(this.href);return false;

[killerme]

thanks rob - I'll get on that straight away

[CovKid]

Seems odd that charging diminishes when engine is under load. Think I'd be checking belt first anyway.

[killerme]

I have refurbished the alternator and that is definitely charging now, though not fantastically. When engine runs the battery is at about 12.6. I think it should be about 14.7 shouldn't it? But I still have the ignition light slightly coming on when going uphill or when I accelerate hard. I still have a bit of a chirruping sound as well around the belts.
One problem with the alternator was at the rear there is a plastic housing that the spine revolves inside. This was distorted which meant movement at the front end (not a great description sorry).
I do have a problem that there is a spacer missing (I think) below which means the belt probably isn't running true which is why this distortion has happened.

Any comments welcome

[CovKid]

I'd be putting that alternator in for refurb. Go to the right place and you can get it done for sub £50. If the bearings are on the way out, it won't last long. 12.6 is battery voltage. I'd say its not charging at all. As you say, should be around 14v.

[killerme]

But that's what I'm saying - I've already done that. £65 and it came back beautifully cleaned up and they assured me it was working fine. Could it be connected to the interconnections with the leisure battery?

[adie89]

Check the alternator output at the alternator terminal, that should be 14volts and a bit, then check again at the battery. If it's significantly lower its your wiring/connections. The gauge wire on these buses is already very low and causes a lot of voltage drop, any dirty or not fully tightened connections will make it worse

[Campermad]

Do you have a split charge? Could this be still drawing power for leisure batrery at a time you need more to your engine battery

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[killerme]

Sorry to reply so slowly but had to go up the north coast temporarily. Thanks for the help though. I checked the alt output (red on the output, black on the alternator casing or on the minus on the battery) and that was still only 12.38 when running so I'm guessing that the alternator hasn't been properly overhauled and it isn't charging so I'll take it back asap. In response to the other points - yes there is a split charge so that could be an issue, and also I wondered if there was a bad main earth could that also be a source of not charging? Hopefully we have got down to the core problem anyway.

[killerme]

Solved. A lesson for all newbies like myself. The solution is often simpler than you imagine. We always fear the worst rather than look for the obvious. I hadn't tightened the belt hard enough. Now I'm getting a full 14.3/4 when running now.

Thanks for the comments - all much appreciated. I can go for the MOT now.
cheers

[killerme]

Also the belt was knackered after sitting around for a year and needed replaced