Alternator Questions

[andyborris]

Alternator on the Pug 205D is putting out 16.5 volts, which might explain why the battery won't hold a charge now!

So is this the regulator on the back of the Bosch alternator?



And do I just swap for a new one? Also, where's a good place to get one?

Thanks

[Rich]

Indeed, that is the regulator. If you google the P/N (the bit under where it Says BOSCH) you will find an exact match, and even OE ones.

[mk2cossie]

Pretty much just replace with a new one as said above.
However, the contacts in the alternator on the shaft may need a slight clean up/polish

[andyborris]

Thanks, for once I guessed right! But it's always to good to get confirmation.

[mk2cossie]

Also, if you can get genuine and justify the price, get an actual Bosch one

Mickey mouse parts generally do not fit brilliantly, at least that's my experience anyway

[kevins]

Mar 21, 2021 10:26:31 GMT mk2cossie said:

Also, if you can get genuine and justify the price, get an actual Bosch one

Mickey mouse parts generally do not fit brilliantly, at least that's my experience anyway

If you do go for a Bosch one get it from a reputable source, nowadays just because it says Bosch doesen't mean it is.

[andyborris]

Well, swapped the new one in and I'm getting a voltage reading of 1 on the new battery.

Guess it didn't work, the part of the rotor the regulator contacts is pretty worn, so I'm guessing it's a fail.

Shame really, can't really justify the price of an alternator on a car I'm not using and that's worth less than £500 with an MOT.

[vitesseefi]

Does not compute..... if it was putting out 16.5v before the generating ability is there....

Suggest checking all the contacts including the earth sleeve on the mounting screw and also that the alternator is earthing through it’s mounts. I know this last sounds weird but corrosion can prevent proper earthing and that leads to strange things, like loss of ability to regulate, because the regulator can’t properly see the battery voltage.

Suspect a proportion of alternator “faults” are fixed by the cation of swapping remaking the earth rather than the new alternator.

Remanufactured alternators are pretty cheap.

Nick

[welshpug]

find a local old boy in a tin shed that rebuilds alternators would be my next port of call if you don't feel you can fix it.

you should have at least battery voltage (12.5 or thereabouts for a healthy battery) when testing at the battery, so I think your testing method may be flawed, have another go!


your alternator is the same body fitment as the gti, so very easy to find a replacement, join up one of the many 205 groups on Facebook and you should be able to find something pretty quickly.

the slip ring is the part attached to the main shaft, two copper tracks joined to the main windings, they are glued in place.

[andyborris]

Will check the alt earth, didn't think of that!

Tested the same way when I had 16.5V and a fried battery, multimeter on 20V and across battery terminals?

[Rich]

Mar 27, 2021 8:51:34 GMT andyborris said:

Well, swapped the new one in and I'm getting a voltage reading of 1 on the new battery.

Guess it didn't work, the part of the rotor the regulator contacts is pretty worn, so I'm guessing it's a fail.

Shame really, can't really justify the price of an alternator on a car I'm not using and that's worth less than £500 with an MOT.

Yea, as mentioned you can't have the engine running and the battery showing 1V, that's not actually possible. The XUD needs about 7-9V at least to allow the solenoid on the diesel pump to let it run. Definitely check again.

[andyborris]

Ok, the saga continues!

Fitted a new alternator, I'm getting a healthy 13.5 volts across the battery while the engine is running, did the headlights on while battery is disconnected and they shine nice and bright.

But, (you knew that word was coming!) the ignition light stays on?

Surely if the ignition light isn't working, the battery wouldn't charge?

Advice please!

[squonk]

It suggests that the alternator has a problem (unless there is a wiring fault) In some fault conditions the alternator will still charge but the light will remain on. The fact that you are seeing 13.5V at the battery suggests that the alternator is 'sort of' working. However, it does have a fault and if the alternator is new it should be replaced under warranty.

[andyborris]

Thanks, getting good at taking the alternator now!