Biggest available Alternator for W124

[ladomani]

guys am here again -- sorry i ask soo many questions hope they are not too much eh?

well i think if you are installing a sub, amp , A/C you would need a big alternator? I would like to know the biggest available alternator and also is there any bad implication for changing the factory install alternator?


thanks guys

[Michael]

What car are you starting with? Year & model would help

[ladomani]

Geee I missed out the details , well i am not a technical guy but it is a W124 230E i think 89 model. hoppe this helps?

[Holson Adi]

When the alternator in our 230E died, we had it replaced with either an 85A or 95A Bosch Rebuilt unit... it's worked very well ever since.

[ladomani]

Hi guys ,
Thanks for the info Holson Adi. I think i will go in for the 95A cos i want the biggest . But I still have some questions not answered.

1. How will u know your alternator is going bad (dont want to end up wid a dead battery before i know ).

2.are there any side effects (bad ones) if i install a bigger one than stock? e.g on the cables , lights u know that sorta thing?

3.do all the alternators fit into the stock placements or their adapters or washers or other things needed to do the upgrade?


i have searched the forum there seems to be no answer to these q's of mine.

[Holson Adi]

If I think about it again, I'm starting to doubt that it was 95A.. but definitely it was around 80+/-10A.

The car does have a pretty awesome Alpine Amp (6 channels actually) and two 10" subs, etc.

I think I got ripped off when I bought that rebuilt alternator.
I remember reading here somewhere that when the battery is dead/dying but the charging light does not come on that means that it could've been as simple as putting in new regulators and brushes...

Of course the dealer just told me to put in a new alternator. I really was kinda stupid about these things (not that im any smarter now) that I didn't check whether or not he gave me an 80+/-A alternator or whether it was the stock 55A(i think) unit.

I think all they did was put the alternator in and the belts were changed, that might've had to do with the pulleys being different.

I guess to prevent that all you can do is check the charge every now and then. I think it's meant to register 14+ V when the engine is running.

[ladomani]

Hey thanks Holson Adi,
I 'll check my alternator too this weekend and also try replacing the brushes and regulators to see if thats where the problem is.

[Ashman]

Check the brushes in the alternator....

My car has two amps running and AC on whenever I drive, car has no problems.

I plan on adding a different amp to change out the one amp with, and changing the radio out..

I havent seen any problems so far though with the alternator.

They make two for the W124 I believe. the 70 amp and an 80 amp found on later cars. The 80 amp one requires a different wiring harness than the 70 amp one.

Definately check your brushes int he alternator if they are worn, it wont charge properly.

Alon

[ladomani]

hey guys,
cool , just cool , found the brushes were worn , but couldnt do the soldering thing , just bought the complete kit and fit back on .

The alternator is doing just fine now , thanks guys , this place is da bomb.

Ashman , i'll look out for the alternator 80 Amp cos i want to also put an amp in the car to run my rear speakers.


gee thanks all

[gsxr]

I'm also interested in upgrade my stock 70A alternator to something more beefy, at least 100-120A, preferably 143 or 150A. I searched the EPC at length and dug up all the 100A+ part numbers I could, added MB list ("dealer") prices, and then looked up the prices at *************** and put it all in an Excel spreadsheet. You can download it here:

http://www.meimann.com/images/mercedes/W124_stuff/MB_alternators.xls


(The first 70A alternator is what's stock on my car, btw.) The problem is, I don't know if there is physically room for the bigger alternators to bolt up to my stock bracket. And, I don't know if the pulleys will interchange, or if the pulley designed for the 1xx amp units will work with my serpentine belt. Has anyone done this upgrade? Satish at MBCoupes.com put a 143A on his, but the 143 and 150 amp units were designed for his M119 engine in the first place. The biggest used on an OM603 (my engine) is 100A and I was hoping for bigger than that. Wiring isn't a problem, I'm an elektrishun and can handle that part. Oh, there are photos of the 100-120A units at this URL:

http://www.meimann.com/images/mercedes/W124_stuff/


Don't have any photos of the 143 or 150A units - if anyone does, please let me know... thanks!


Best regards,

[ddrake3]

Is such a bigger alternator worth it since the voltage regulator will regulate what the alternator puts out anyway? Unless you're constantly pulling the extra 40 to 60 amps, which would be hard to do unless you have an electric stove, oven and clothes dryer, and several rooms of your house hooked up to your battery?

[Ashman]

you can have yours rebuilt to a huge amperage, but it costs $$$

It cost $450 to get my dad's Rolls Alternator bumped up from 70 amps to 150 amps.

Alon

[gsxr]

Alon,

I'd prefer to just bolt on an OEM high-output alternator. That way:

1) if I sell the car, I can plug back in the stock alternator;
2) I won't have to use the lousy blade connectors to connect large cable to;
3) I'll have a spare stock alternator for my other car;
4) if the OEM HO one fails I can get another from normal suppliers.

Oh, also, most "rewound" high output models put out very little current at idle, especially if they were originally less than 70-80A with the physically smaller housing. I expect the real Mercedes original 1xx amp units won't have this problem (but will be physically larger.)

I did some more checking on the EPC, it looks like the pulleys should interchange between all the alternators and they all should use the same width belt. So it boils down to if the HO alternator will physically mount up to my OE bracket (iffy), and if the protrusion of the pulley is the same (likely). There was a different bracket used on my engine for models with the 100A alternator, I might buy that and take it to the dealer, and have them pull a 143-150A unit off the shelf so I can see if it will mount up. I was hoping SOMEONE had attempted this before. I updated the spreadsheet again, too.


Regards,

[Ashman]

exactly. The high output ones don't charge well at idle, we have found this out on the rolls, so we are going to have it wound down a bit to a lower amperage so it charges at idle.

Alon

[ke6dcj]

Do a search for "alternator" and username "gsxr".

You can get a used 143A 1996+ S420/S500/SL500 and it should bolt right on.

:-) neil