Alternator brush pack / regulator types & part numbers

[California Dreamin]

Here is a BOSCH 65ah unit with the push on block connectors (female spades)
Scroll down to see the pics...blue label appears to be 65ah, looks like green labels are 45ah (mine was dark pink 90ah)

http://www.ebay.co.uk/itm/VW-TYPE-25-T2 ... 416e3a4ccc" onclick="window.open(this.href);return false;

And here is a 90amp unit...pink label....not that clear but definately has the stud/eyelet on the rear.

http://www.ebay.co.uk/itm/Vw-t25-90-amp ... 1e74f7c661" onclick="window.open(this.href);return false;

Two more 90amp units with original Bosch Regulator brush packs still in place (note 14volts) replacements are generally rated higher (14.5volts) and better suited to modern calcium Silver sealed batteries of today.

http://www.ebay.co.uk/itm/classic-volks ... 2c665f223a" onclick="window.open(this.href);return false;

Note* late 65ah units also went to a stud and eyelet connection.

Martin

[Oldiebut goodie]

I've got a 45A in the workshop and can confirm that it has a green label.

[1664]

Cheers chaps, I'll add that coloured label information to my Haynes manual; I like to suppliment it with any additional information discovered on my travels.....helps any prospective future owner and helps me as I have a memory like a sieve

I am now waiting on Mr Postman

[Cruz]

I never get 14v at my battery when the engine is running. It's usualy 13.8 then drops to about 13.2 when the headlights are on. I assume that's because of old wiring?

My alternator is only 6 months old (lucas)

[California Dreamin]

Thats an interesting one Cruz and does hint at the inherent design 'shortcomings' of having such a long cable run (petrol engined T3's) however, in theory at least, without any load and engine running, one would assume the alternator charge current (proportion of what the alternator is capable of delivering) would be quite small....perhaps just 5 - 10amps (running the ignition system) assuming the battery is fully charged. I would have thought that with such a low current flow and relatively large cable capable of carrying 150amps plus, that the resistance and therefore the voltage drop would be minimal at that low amp draw.
Waffle/Waffle/Waffle.......
Try checking output at the alternator....there really shouldn't be more than 0.2 volt difference (volt drop) between the two readings (according to the IMI's own charge test methodology)
If you are getting only 13.2 volts at the alternator then I suggest the regulator is faulty (remember the voltage should remain fairly stable as it is the current/amps output that changes) Yes I accept that there is some variation depending on alternator load but refering to the volkswagen data I have the tollerance on the original Bosch/Beru units was 13.9 - 14.2 volts (0.3 volt variation). However, In reality and with our long cable run I accept this may be a little bit more.
I think this is where the newer 14.5 volt regulator brush packs maybe particularly useful as they should still maintain over 14 volts even with a little voltage drop.

Martin

[1664]

I get 14v at my batteries with the engine running


or sometimes 18v



Yes, I'm still waiting for the postman

[ghost123uk]

@ Cruz and Martin et al,

I found this too with my relatively new alternator and brand new 14.2 volt brush pack. In fact it was this phenomenon that prompted me to fit the new, higher voltage brush pack, but it made no difference to the voltage at the battery, tho reads 14 at the alternator I checked all cables and connections and they all are / were sound. iirc, I mentioned this further up ^^^ and I put it down to current draw over cable resistance.

However, it is less than ideal (as has been well mentioned), as "we" would like 14 volts on our batteries, esp the leisure one. When the frost and sub zero temps abate I intend to run a temporary "supplementary" cable (of around 20 amp capability cause that is what I have) and check battery voltage with that connected. If (as I suspect) it improves I may well fix the cable permanently. Will report back with findings.

Waste of £32 on 2 different brush packs though to find this out

[California Dreamin]

But.......and I say this with the utmost of respect as I know you are very competent person, you should have checked the output at the alternator before buying the new part.
I know I was one of the ones commenting on the original post and I am not sure if this was suggested....my apologies if it wasn't...perhaps a mental note* for future reference as in retrospect this should be one of the initial tests.

Martin

[ghost123uk]

True Martin, I should have, but like I think you intimated in that previous thread, I too assumed that the voltage at the battery, with only a modest (ign) load, would be the same as at the alternator (in view of the heavy, low resistance cable). When I suggested testing the voltage after it settled down for a minute or two, and you said it should be at the regulator output immediately, I was allowing for voltage drop due to starter drain being replaced down the cable. Turns out, even with that in mind, we don't really get a meaningful reading

If it wasn't so VERY cold and VERY frosty, I would go out now and do my "supplementary charging wire" experiment !

[California Dreamin]

Perhaps a pair of jump leads VERY CAREFULLY linked together..not sure how you would connect to the alternator ( maybe a screwdriver pushed down the back of the output terminal and the jaw of the jump lead on the screwdriver shaft...it would need to be a good connection and obviously insulated from the body (might be a two man job lol).

Martin

[California Dreamin]

But then....the issue could just as easily be with one of the earths....braided earth on the gearbox end/battery to body lead etc. Although these are shorter because they are using the body as 'earth return'.

Martin

[ghost123uk]

Perhaps a pair of jump leads VERY CAREFULLY linked together..not sure how you would connect to the alternator ( maybe a screwdriver pushed down the back of the output terminal and the jaw of the jump lead on the screwdriver shaft...it would need to be a good connection and obviously insulated from the body (might be a two man job lol).

You could, but a bit "iffy" re sparks etc. I have some nice cable and will solder some HD eyes on each end If it works I will route it underneath permanently.

But then....the issue could just as easily be with one of the earths....braided earth on the gearbox end/battery to body lead etc. Although these are shorter because they are using the body as 'earth return'.

Doubt it's that as it spins over like a good un

[California Dreamin]

Quote: Doubt it's that as it spins over like a good un

Therein lies the conundrum/oxymoron....substantial voltage drop (without load) yet apparently able to delliver the required 120 - 150amps needed for starting. Where as I could understand the other way around.....very little voltage drop (without load) but slow cranking....that makes sense.

Martin

[bigherb]

I would recheck your connections again.
My 30 year old wiring only looses 0.65v down the charging circuit under load.

Fully charged battery with just the engine running @2000rpm


With main beam, driving lights and blower switched on at the battery approx 30A load


And at the alternator.

[California Dreamin]

Bigherb.....is that last reading (13.93) with load at 2K? looking good.

Martin