Club 80-90 Forums

I've checked the Wiki and other posts but can't find similar...this ones a bit odd.

Van starts fine, every time!

Over past 3 days, after about 10 min, the battery warning LED illuminates. If I then turn on headlights, wipers or radio, the led dimms or, in the case of headlights, goes off all together.

Battery appears fine (putting oncharge right now but appears fully charged). New (well refurb) altonator this year.

Also, with all electrics swiched off /engine running (LED has come on by now) when I rev the engine, LED becomes brighter.

Your thoughts please

Nige

The 'ignition' or alternator warning light comes on when the key is turned to the A2 notch. this then sends a current of @4 4.5 amps to the alternator field coils and this current, once the engine starts excites the alternator, which generates its own current and feeds the field coil and when the voltage equalises it extinguishes the warning lamp.
Obviously this is not happening in your case. I am wondering if the exciter wire that feeds the field coils is faulty and the alternator is self exciting which would mean it will still put out power.
Have you checked whats happening with a meter? Eg voltages at the alternators terminals, battery voltage before and after the light comes back on?
I think its either a regulator issue or a exciter wire issue, could be a fault in the wiring I guess, but perhaps whip the alternator off and have it checked.

Thanks for your reply,

Don't have a meter at the mo but will sort.
at the rear of the altenator I have 2x red wires and one blue/turquoise wire. I know where these co. o the right of the altenator (looking from the rear of the vehicle) there is a 11/2in 'post'. attached to this is a grey whire with some sort of connector on the end (black plastic 3 pronged male). I've just noticed this (in the dark) appears verry clean inside the connector. indicates somethings come adrift. should something be attached to this?

...All ok with ameter....what next...any suggestions plz....the battery was fine when I put it on to charge btw

Hi rusty
Whats happening then?
You will have a battery voltage that we will call A, how many volts is it?
We have a voltage at the exciter wire with the ignition at A2, we can call this B, how many volts?
When you start the van up what happens? Does the battery voltage immediately rise? To what?
When the red light comes on what are the voltages at A and say at the alternator output terminal (C)? If you have a battery light coming on 'after a while' faulty reg or exciter wiring OR faulty van wiring OR possibly a sticking brush in the carrier, would be my usual suspects, I had a Transit that we suspect used to do this, never found out for certain because it was completely intermitent.
Have you checked that the alternato exciter wire feed from the ignition is OK? Get a long piece of cable and check either end of the exciter feed wire with meter, resistance should be low.
All I can suggest then short of an online alternator rebuild is taking alt to an auto electricians and getting them to put it on a test rig.
Or as others may suggest if its just a case of putting up with the light and it aint doing any harm then live with it until it turns into something, or doesnt.
HTH but I dont have a magic bullet for this one. Soz

Could be that your alternator is overcharging and by turning all the services on the light is going out due to the overcharge being soaked up by lights wipers etc, when alternators fail they don't always undercharge get a meter on it and you'll want to see between 12.8v and 13.5v .

Where abouts in the country are ya there could be a techy on here who lives near ya.

hi

readings seem fine...i live in stroud gloucestershire

Nige