More powerful alternator for gasoline W123 200

[Pentium100]

Hi, I just created an account.

I have a gasoline powered (also runs on LPG) W123 200 (80kW version) and I think that I need a bigger alternator. The law says I have to drive with headlights on all the time, then in winter I need rear window heating (and the intake manifold heater draws a lot of current). I also like to turn up the volume Add to that the fact that my work is only a few kilometers away and I get an undercharged battery. So, I think replacing the alternator with one that can provide more power would be good, especially in winter.

I googled and looked on ebay, but all I could find was alternators that would fit a diesel W123 with no information whether they wold fit a gasoline one.Connector difference is no problem, but the alternator should fit in the place it's supposed to go.

Are there any alternators that provide more than 55A current and fit a
M102.920 engine?

[porkface]

1985-86 190e has vbelts and a 70 amp alt, bosch rebuilt is al65x, maybe it'll work. i remember it SHOULD be the same belt setup. the 87-later 190s also use a 70amp but the bosch rebuilt is al160x. serpentine belt and a different harness i know. does it have the same frame and can it bolt to a vbelt engine with just a pulley swap? don't know, but they are easier to find. if yes, than can a 90amp from a late 124 fit? and will a heavier amp alt. slow down the engine? I drove a gray 123/200d wit a/c and it as WAY under powered. never drove a 123/200e but i have my doubts.

i've worked on 1 gray 123/230e in 20+ years, don't remember driving it though. i do remember it was red and an odd looking thing under the hood, compared to the 85 190s. and we had a bunch of 190s come through, vbelts and serp belts. maybe it was just the body that made the 102 motor look funny-been too long ago. 99% of the 123s i've done had 616 or 617 diesels. good luck, chuck.

[Pentium100]

The belt in my car is a V belt.

I am concerned about the mounting bracket - I do not know if the alternator that fits in a diesel W123 will fit in mine (which is 200, not 200e - a model with a carburetor).

As for power - the current alternator provides 660W of electrical power and probably loads the engine at ~800W. If the bigger one takes 1.5kW from the engine I most likely won't notice (I probably will notice when I install an AC in my car).

200D is 40-44kW engine, mine is 80kW, so much more power.

[porkface]

that why i said 190e 85-86. leave the diesels out of it. good luck, chuck.

[Pentium100]

I have taken a picture of the alternator in my car with the bracket. This is how it needs to be mounted.




I also tried to take a picture of the model number, but it's not very legible as the label is worn.



Is this how the alternator is mounted in the diesel cars or the 190e?

[porkface]

the ONLY way to be sure is to take yours off and look at all the choices. you keep saying diesel, maybe it'll fit, i don't know. but because your 123 has the same 102 engine as an 85-86 201/190e, the bigger alternator has a better chance. anything is going to be an experiment until someone proves it out.

now, your alternator was used in the 70s here on some engines and was replaced by mercedes to a 74a. bosch rebuilt is an al117x.

until somebody looks at them both or you buy it and try it, no one will know. the us cars always bigger alternators than europe. that's why i suggested the 85-86 190e, same motor, more amps. good luck, chuck.

[Pentium100]

Well, I found one 150A alternator for sale on ebay specified to fit a diesel W123, so I asked the seller whether the alternator would fit in the place of mine (gave him the number on the alternator), the seller said it would so I bought it.

It did fit, and now I get 14.1V at idle with headlights and fan on, prevoulsy I had something like 13.2V unless I revved up the engine.

[vstech]

Practically every mb I have seen uses the same alternator frame. The larger amp alts need longer belts and wiring, but all can be made to fit.

[jay_bob]

Great, just be sure you have also upgraded the wiring from the alternator to the main terminal block.

[Pentium100]

Originally Posted by jay_bob

Great, just be sure you have also upgraded the wiring from the alternator to the main terminal block.

Since the new alternator uses different connections (screw terminals instead of a three pin socket), I had to replace the wire, so I used a 16mm^2 wire and connected the other end to the battery, which is quite close to the alternator. The wire drops about 0.03-0.1V (IIRC ~5A current results in ~7mV voltage drop).

The original belt was good enough, the only problems I had were getting the "gear" screw out (it was quite wedged in there) and getting the new alternator in the bracket (it probably was just a little bit thicker than the old one).