Higher current alternator
 

The stock alternator is too weak to supply enough current to my 1987 300d. With the aux fan, a/c and euro lights, battery life is poor- 2 years. What I would like is to replace it with at least a 100A Alt. without changing the wiring or mounting. Has anyone actually made this change? The '95 S350 has a 100A Alt.

Search "Saab alternator" for higher output information. I would be concerned about the belt being able to handle the extra load.

Euro lights draw the same current as US lights.

The positive wire should be upgraded to handle the extra current. Pretty simple job if you're in there anyway.

Did it on my '87, well worth the effort, I just went to an internal-fan 90a and was rewarded with good voltage at idle.

Have you measured the voltage at the battery with everything running?

I put a 150 amp alternator on my 77 450 SL because I had the same problem as you. That in itself fixed everything. I bought it on ebay for $124.99. Oddly enough this also fits my 300D. I now can have every electrical option at the same time without any low voltage problems.

theres a HUGE thread on here I think from GSXR? which details this mod.

There are a few options for bolt in, but you will need the later 124 wire harness for plug and play. I used a 120 amp from later 124 but you could go for the 98-99 models and get either 143 amp or 150 amp. My 120 amp came with new pulley installed and was perfect offset so it bolted right in. But Ive heard the 143 amp or 150 amp may require you to remove your existing pulley and install it on the new 1. Its all detailed very well in the thread I mentioned.

The funny thing was the 120 amp I bought (from Ken at The Benz Store) was CHEAPER than the wimpy 70 amp unit. Ken also set me up with a used wire harness for extra $15 so the job was simple.

And dont worry about the belt, its plenty strong to drive the alternator, you wont have an issue.

So now my headlights are brighter, battery lasts longer, squirrel cage motor blows like a hurricane. Why MB ever saw fit to use such a low power alternator is beyond me...