Is my alternator knackered?

[Drucifer]

Ok so have the red battery light on, replaced the battery, replaced the two red cables from battery to alternator as these had corroded to near powder and still get a red light.
The battery with no ignition is showing over 13V running it is showing 12.6V, at the alternator I get the same between 12.3 and 12.6, so do I need a new alternator or is it something else?

[lloydy]

voltage regulator on the alternator is where i'd start, seeing as it's only a few quid
http://www.brickwerks.co.uk/index.php/v ... 3-all.html" onclick="window.open(this.href);return false;

[California Dreamin]

Check the alternator has the small blue exciter wire connected at the back...

Remove the regulator from the back of the alternator...brushes should be at least 10mm long..although this is only going to assess physical condition as the electronics inside the brush pack could still be faulty.

Martin

[ghost123uk]

The battery with no ignition is showing over 13V running it is showing 12.6V, at the alternator I get the same between 12.3 and 12.6,

That's a bit odd that your getting over 13 volts at the battery when it's not charging. But it makes no difference to the advice given ^^^.

Aside =

voltage regulator on the alternator is where i'd start, seeing as it's only a few quid
http://www.brickwerks.co.uk/index.php/v ... 3-all.html" onclick="window.open(this.href);return false;

Odd that Brickwerks have not quoted what voltage output the regulator he is selling has. I have emailed him suggesting he puts that info in the blurb.

[California Dreamin]

I find the 'Suits all models including 90ah' interesting. I'm no expert in part numbers/suitability but I believe that there are two different diameter slip rings (28 & 32mm) found on the Bosch alternators fitted to our vans. These require a slightly longer/shorter brush housing depending upon Bosch alternator model.

In theory..fitting a regulator designed for a 32mm slip ring to an alternator which has a 28mm, would expose more unsupported brush and visa versa, a 28mm model fitted to a 32mm slip ring where the brush housing may actually catch the slip ring because the housing protrudes more.

A 14.5volt regulator brush pack may indeed be more suitable for the calcium silver technologies found in modern batteries which ideally need a slightly higher charging voltage.

Martin

[ghost123uk]

When I was buying a new one for our Hi-Top (as I wanted to "up it" to a 14.5 volt one) I noticed the sellers often do not mention this. The one I bought for my 60 Amp alternator fitted fine. I wonder if they are making them "universal" by going half way between the 28mm and 32mm ones ?

Note to self = get a 14.5 volt one for the Tin-Top now it is "back home"

[Drucifer]

Ok the blue wire was broken and twisted to another bit of wire which plugs into the alternator, this appears to be burnt out as very old and thin. Will try replacing this when I get home later and see if it works any better.

[Highroller]

Just for your info. I fitted a new regulator brush pack from brickwerks to my 90Ah alternator on Sunday. It is stamped as being 14v on the back but I am getting 14.5v at the exciter connection. I am only getting 13.08v at the battery though.

[California Dreamin]

Ok the blue wire was broken and twisted to another bit of wire which plugs into the alternator, this appears to be burnt out as very old and thin. Will try replacing this when I get home later and see if it works any better.

There is you problem! make a nice clean repair (solder if you can with some new wire) and it should make all the difference.

Martin

[California Dreamin]

Just for your info. I fitted a new regulator brush pack from brickwerks to my 90Ah alternator on Sunday. It is stamped as being 14v on the back but I am getting 14.5v at the exciter connection. I am only getting 13.08v at the battery though.

When running...what voltage are you getting from the two large spade connections (connected) rear of the alternator?.

Martin

[California Dreamin]

I found this....

http://www.ebay.co.uk/itm/VW-BOSCH-1197 ... 8394wt_954" onclick="window.open(this.href);return false;

Based on the reference number I found this info:
OEM Part Number: 068-903-803/D

This voltage regulator is for Bosch alternators and fits specific VW T25 and T4 models 1981–1986. On T25, it fits all Diesels 1981–1992 and all 1900cc and 2100cc petrol models 1983–1992. On T4 it fits all 1800cc-2800cc 1990–1996. It's well worth replacing if you are in any doubt as to its condition.

Looks like a goer £12.50 but is FREE POST! However, if I were ordering I would add a note about requiring a 14.5 volt version because they are listed as a 'Febi' further down the page yet clearly using a picture with 'Electrix' brand.

Martin




Martin

[Highroller]

Just for your info. I fitted a new regulator brush pack from brickwerks to my 90Ah alternator on Sunday. It is stamped as being 14v on the back but I am getting 14.5v at the exciter connection. I am only getting 13.08v at the battery though.

When running...what voltage are you getting from the two large spade connections (connected) rear of the alternator?.

Martin

With engine running I'm getting 14.5v at the large spade connectors on the back of the alternator but only 13.08v with engine running at the battery.

[California Dreamin]

OK...seems pretty straight forward then....as the main cable runs straight to the battery it must be a break/high resistance in...either the main positive lead or a main earth on the engine.

Martin

[California Dreamin]

I've had a reply from the ebay seller about those regulators.....here is what he said.

Hi, the ones we have in stock are Topran of Germany & are 14.4 V & is a direct replacement after our initial listing of the one in the picture

That's an increase in regulated voltage over the original supplied so a thumbs up.... and better suited to charge newer battery types.


Martin