Replacing alternator regulator 200A - recommended parts?

Anyone got any advice on replacing the alt regulator? Have a genuine Bosch fitted. Just clambered under to read the part it's a BR14-M3 part # f00m145248

Replacing due to lower voltage than would like when running and slight leak draining the battery through it when standing.

I have a 200A unit installed and was curious if all the regulators are the same, if any 3rd party OEM units were any good and if anyone had a line on the best place to get them? Searching here they are about £50 from Germany.


Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

The regulator is what determines the "200 amp" output of the alternator.
So you certainly can't swap in a regulator intended for a 90 amp unit.

--dick

It is almost impossible to find spec sheets for these things!

Apparently F00M144139 supersedes part 248 (source: https://groups.yahoo.com/neo/groups/sprinter_westfalia/conversations/messages/9519 ) so I have ordered that from a reputable seller.

If anyone has a line on finding the spec sheets from Bosch that list the ampage output please do let me know.


Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

dick - I've called Bosch Technical direct, and they confirmed that F00M144139 replaces F00M145248. More importantly they have confirmed that the same regulator works for all Amp ratings up to an including 200Amp.

I've got a 139 on order due today for mine and will confirm fitment and photograph the replacement when I stick her in.#

I have asked for a spec sheet, but they state they don't supply those to the public as they don't want Chinese copies appearing.

If anyone else wants to confirm, you can contact your local Bosch folks. These are mine:

http://uk.bosch-automotive.com
Automotive Aftermarket
Address: Robert Bosch Ltd
Broadwater Park
North Orbital Road
Denham, Middlesex
UB9 5HJ
E-mail: contact@uk.bosch.com
Tel: 0844 892 0115

Arnie_Oli said:

dick - I've called Bosch Technical direct, and they confirmed that F00M144139 replaces F00M145248. More importantly they have confirmed that the same regulator works for all Amp ratings up to an including 200Amp.

...

Click to expand...

I guess this is an obvious observation, but I can't resist.

The vehicle voltage and system requirements remain the same regardless of alternator amp rating. The output capability basically is dependent on the sizing of the main coils and diode bridge. The required excitation current may be higher or lower (percentage wise), but as long as the regulator is sized for worst case, that is not a problem.

Nice of Bosch to keep the regulator and brush design standard as to the different alternator amp ratings.

Good information. Thanks for checking and reporting back.

vic

The reason I've been after the technical specs is because there are a number of unscrupulous sellers out there that charge more for the "200A model".... I've seen prices of upwards of £90 for a regulator when it's (at best) a £20 trade part. Just made no sense to me that the same part number cost fluctuated so much. It was also a major disappointment that Bosch/Merc/Dodge keep the info to themselves.

EDIT: Sorry Vic/dick I may have misinterpreted what you were saying. I was just pointing out that it's the same part that's sold for the 90Amp, 150A and 200A etc rated alternator. There may be other parts, but the common ..249/..139 part works for the lot, there are just retailers that sell the same part three times at different prices.

I must admit to being curious... how do they prevent damage to the alternator's coils if one regulator fits all?

In Ye Olden Daze of DC generators and separate dual-coil regulators, the regulator had a "voltage" coil and a "current" coil.
The voltage coil would pull in the relay (thus energizing the field coils to create power), and the reversed-winding current coil would force it to drop out if the demands were too high.

That said, looking at the parts catalog for the 2006 T1N (http://www.diysprinter.co.uk/reference/06va-parts manual.pdf), i see that indeed they list three alternators (90, 120 and 200 amp), but only one regulator.
(90: 05134199AA , 120: 05134204AA, 200: 05117587AB, regulator: 05135837AA )

(((the 2005 catalog (http://www.diysprinter.co.uk/reference/05va-parts manual.pdf) only lists one alternator: 05134199AA and regulator: 05135837AA )))

--dick

autostaretx said:

I must admit to being curious... how do they prevent damage to the alternator's coils if one regulator fits all?

...
--dick

Click to expand...

Are you assuming that the regulator limits the output, not the limits of the alternator coils/diode bridge?

Excitation vs alternator coils of itself can be self limiting. Does more excitation of the unit exponentially result in more output than designed when pushed into an undercharged battery?

I thought that the purpose of the regulator was to control system voltage (within limits) and to avoid over-charging which can ruin a battery.

vic

Aqua Puttana said:

Are you assuming that the regulator limits the output,

Click to expand...

... I was...

not the limits of the alternator coils/diode bridge?

Click to expand...

Well, the diodes are part of the regulator assembly... (i think)

And if you're hoping/designing the alternator coils to limit current (given that you're going to get 12 to 14v of field current), you've got to be pretty precise in your coil turns count and iron poles to limit the B-field enough to prevent the spinning alternator from generating too much current (i.e. overheat itself) for its wire size, BUT still ample enough to develop full rated charge at less that full-tilt engine speeds.

Excitation vs alternator coils of itself can be self limiting. Does more excitation of the unit exponentially result in more output than designed when pushed into an undercharged battery?

Click to expand...

... or into heavy-current accessories all being turned on at once (plus charging the Aux battery).

I thought that the purpose of the regulator was to control system voltage (within limits) and to avoid over-charging which can ruin a battery.

Click to expand...

One (or, at least *i*) would hope that there's a dollop of "save the alternator from self-destruction" tossed in there, too.

But that may now be "old-school" thinking. too...

--dick
p.s. oh, well... at least it's nice to know that even a 90 amp alternator has 200-amp-rated diodes...

Most of the time only the brushes wear out on the regulator anyway so they can be changed with ease ! search you tube and you will find this polish fellow who speaks with an Irish accent who has nice detailed videos on this subject . ( Bosch alternator )

autostaretx said:

...

One (or, at least *i*) would hope that there's a dollop of "save the alternator from self-destruction" tossed in there, too.

Click to expand...

There kinda is in that the alternator can only put out so much current. Some confuse vehicle alternator operation with electric motor operation. The use of wound coils make them appear similar, but they are different animals. In my experience vehicle alternator coils rarely cook or burn out. Most times loss of output relates to regulator problems or main diode failure(s).

autostaretx said:

...
p.s. oh, well... at least it's nice to know that even a 90 amp alternator has 200-amp-rated diodes...

Click to expand...

Are the main diodes in all of the different sized alternators identical?

The regulator diodes? They are to supply the field coils. They have nothing directly to do with the main diode bridge.

vic

I fully agree that the regulator does not have (and/or does not adequately thermally couple to the metal) the "heat sink" capacity needed to handle the charging-current diodes. (egad... it's been 40 years since i last changed out an alternator's diodes... on my '65 VW squareback)

One of the service documents (which i can't find at the moment ) had a representative schematic of the regulator's internals.. and appeared to lump the diodes into the regulator's "box".

--dick
p.s. whilst trying to find the above-mentioned document, i re-read the service manual chapter on the "generator"... i was bemused to see that they said to replace the entire generator if the brushes were worn. ((since the brushes are running on slip rings, not a segmented commutator, they shouldn't wear. Thus, if they do, the slip rings are shot ((similar to rotor/brake pad arguments)))

autostaretx said:

...

One of the service documents (which i can't find at the moment ) had a representative schematic of the regulator's internals.. and appeared to lump the diodes into the regulator's "box".

Click to expand...

The brushes are often integral with the replacement regulator.

The excitation diodes are shown in the diagram here.
https://sprinter-source.com/forum/showthread.php?p=511369#post511369

Basically the rated alternator output is a function of the magnetic field and the main coils. The coils don't overload like they do in an AC motor when too much load slows the rotation which affects the back EMF/impedance and results in overcurrent.

autostaretx said:

...
p.s. whilst trying to find the above-mentioned document, i re-read the service manual chapter on the "generator"... i was bemused to see that they said to replace the entire generator if the brushes were worn. ((since the brushes are running on slip rings, not a segmented commutator, they shouldn't wear. Thus, if they do, the slip rings are shot ((similar to rotor/brake pad arguments)))

Click to expand...

I don't necessarily agree with that maintenance concept.

The brushes are in continuous contact with the rotating slip rings. Friction wear and current will reduce the mass of the brushes over time. Some brushes are made harder than others. A soft brush can wear out long before the slip rings become un-serviceable.

If replacing the regulator assembly is desired (eg. - to renew soft brushes), a simple visual inspection of the collector rings should establish their condition.

vic

Aqua Puttana said:

I don't necessarily agree with that maintenance concept.

Click to expand...

... ditto ...

--dick

Given the cost of a new Bosch unit I am not jumping to swap the complete unit until I have to

It seems that the lifespans of the brushes with average use appears to be around ten years or so, obviously mileage may vary but that's how long a similar Bosch model unit lasted on my Golf before the brushes were worn low. I rather wish I had kept the spare bits when I had them but I wasn't familiar with rebuilding alternators back then. Love and learn!


Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

Tada! Chores have arrived in the post

Love the handy label with the "no lay people, just workmen" logo.




Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

Got her out. Not much more life left in the brushes anyway. About twenty mins fudging around underneath keeping the alternator in situ and removing the regulator from underneath while my feet burn in the roaring sunshine.

Obviously disconnect battery...

Much easier if you use an E12 torx socket to move the supporting bracket for the turbo to one side.

Remove the bolts and screws shown, cover from alternator comes off and two needlessly hidden screws (WTF Bosch!) come out and the regulator slides out.

Just about to pop her back in and test now


Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

On the subject of the bushings. This is what mine look like after ten years and 88k miles


There is a lip on them but judging by the depth of the parts only about half worn.


Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

Rebuilt and back up and running. Tested at 13.84v when running. Much better.

Now to see if that parasitic load has gone.



Sent from my iPhone using Tapatalk Pro which means I am probably lying under the van wishing I had a crawler and a large warm workshop I could park in.

Hello Gentleman, what a great discussion. I am new to the sprinter world and have an issue with charging that i would like your input. I have a 2004/2005 Airstream westfalia van with 60,000 miles. recently on the way home from a trip the battery light came on ans would go off an on every few minutes. I pulled over and found that the charge voltage to the battery varied from 13.8 volts(battery light off) to 11.3 volts (battery light on). The electrical system would not charge so i crept home using as little power as i could.

I has heard that the voltage regulator was often an issue so i ordered one from amazon using the correct part number if found on the westfalia group page. I received it and put it in today. fit just fine and looked the same as the original bosch but was made in china. now the alternator is putting out too much volts 15.1 to 17.1.

Should i assume that i got the wrong part and just order the bosch part? Is it safe to drive the van over charging like that? Dash warming light came on when i tried to drive the van.

Thank you very much.

Guy in Tulsa, OK