raycov

i know wev,e been hear before,but i took the wires off the other day to do somethink and now the battery light will not go out when the engine running, i know that if the battery light stay on it will not charge what would you try next.
cheers

orion_crazy_carl

iTrader: (3)

is the alternator connected to the starter ok?

raycov

yes mate

Moonie

Where have you connected the blue (trigger) wire to on the alternator?

If you remove this wire does the light go out?

iansoutham

What did you put the wires back onto?

B+ is the big red terminal
D+ is the one for the dash light (blue wire)
W is the 1/2 phase output and would normally be empty.

Check them first, if not you may have a short circuit on the blue wire as Moonie says.

raycov

yes moonie the light goes out when you disconnect the blue wire

raycov

does this help,just put my volt meter on and the battery reads 25 volts when switched off and there is 13.2 you touch the blue wire from the altenator when the engine is runnig.

iansoutham

Did you want to double-check that voltage please.

raycov

i juist checked the battery and it reads 23.2 volts, it has been standing all night and the engine is switched off ian

iansoutham

Okay, then you are a very lucky person. If that battery really had 25V in it, then you were driving around on what is basically a bomb (anyone who has ever seen a battery violently explode will know what I mean).

Right, it looks like the alternator has gone "open circuit" within the regulator, and instead of regulating @ about 14V, it is giving everything it can (normally no more than 17V though). Check your battery for any signs of damage (bulging, stress marks etc..) and if there are any, change the battery. If not, then replace the alternator (you could replace just the regulator / diode packs but it would be cheaper to do the whole unit).

The reason the light is on even though the engine is running is because the alternator is saying that there is a problem. The light will come on when the alternator output is too low, but also when the output is too high. There is normally 3 diodes in the diode pack, 1 for low output, 1 for high output and 1 for preventing drain-back when the engine is off. The high and low output diodes are both connected to the warning light connection.

I would also check your bulbs, as these are normally the first thing to go when the charging system goes ape like this. Chances are you have @ least one or two blown due to the increased voltage.

raycov

i have just had a 4 mile town drive and the volts read 23,should i disconnect the altenator and get the battery back to about 17 an get a new altenator.

matts1

Ray, shuould you need an alternator, I have one that came with my RS, only a couple of months old with receipt.

I am selling the car and parts, and imagine the new owner will be selling the alternator as it is not required, think it will be about £50.00 plus P&P

Let me know if you need his info via pm.

Matt

iansoutham

I would get the battery back down nearer 12-14V methink, 17V is still too high. What happens when you put all the lights on, wipers, heaters, etc....?