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Hi all,

I've searched around, and I haven't found anything mentioning this in the past....

I've recently upgraded the audio system (new Continental head unit, amplifier, subwoofer, and larger speakers) in my 1986 560SL, and this appears to have also coincided with a decline in alternator functionality....to the point that the alternator finally failed to turn over the engine last week. I need to replace the alternator, but I was curious if there's a recommendation for a higher output alternator for the R107 than the OE. Ideally, I think I need 100+ amp output. I know that the AL129X was an option for the W123 as a higher output amp, but is there something similar that folks have identified for the R107?

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Hi all,

I've searched around, and I haven't found anything mentioning this in the past....

I've recently upgraded the audio system (new Continental head unit, amplifier, subwoofer, and larger speakers) in my 1986 560SL, and this appears to have also coincided with a decline in alternator functionality....to the point that the alternator finally failed to turn over the engine last week. I need to replace the alternator, but I was curious if there's a recommendation for a higher output alternator for the R107 than the OE. Ideally, I think I need 100+ amp output. I know that the AL129X was an option for the W123 as a higher output amp, but is there something similar that folks have identified for the R107?
I've never heard of a high output alternator for an R107 but in the car/audio world I think the folks running high current amp(s) use Singer, DC, Mechman, or US. Links below. Maybe one of the companies could build something custom for you. I think the max output of your stock alternator is 70 or 80A

You said "the alternator finally failed to turn over the engine". Maybe you meant to say your new audio system drained your battery faster than the alternator could charge it?



https://www.dcpowerinc.com


 

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Discussion Starter #5
Thanks for the links - and yes, I meant to say that the battery had been drained to the point that it could no longer start the engine....due to the load from both the audio system and A/C. The problem with a lot of these aftermarket alternators is the fitment in the extremely tight R107 engine compartment, but I'll check with these manufacturers to see if they've done anything for the R107 previously.

I've never heard of a high output alternator for an R107 but in the car/audio world I think the folks running high current amp(s) use Singer, DC, Mechman, or US. Links below. Maybe one of the companies could build something custom for you. I think the max output of your stock alternator is 70 or 80A

You said "the alternator finally failed to turn over the engine". Maybe you meant to say your new audio system drained your battery faster than the alternator could charge it?



https://www.dcpowerinc.com


 

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Discussion Starter #7
Yes, the battery was replaced. However, the electronic components are drawing more amperage than the alternator can provide, thus it's draining the battery to accommodate. The battery replacement would only be short-term until the alternator can be replaced/enlarged.
 

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How do you know that the electronic components are drawing more amperage than the alternator can supply? Did you measure it? If the stock alternator is capable of supplying 80 amps or so, I would think that would be more than enough to run everything you need. 80 amps at 12 volts is 960 watts. Unless your running sound amplifiers of the type found at rock concerts, it is not likely that you are exceeding the alternator output capability.

Can I assume the power supply to the audio equipment is fused? If so, what size fuse is in the line?

Good luck.
 

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Samson uses the stock alternator from the 1996 SL600. I believe its 150 amps. It may be possible that it will just bolt in place but you would have to upgrade your output wiring, which may be very easy on the 560SL. You will also need to swap the pulley.
 

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Before we toss the old alternator, have you checked the voltage regulator?

This is a wear component and will give symptoms of a failing alternator.

He lives on the back and will require you to remove the alternator. Since you're looking for an upgrade, I would take a look at him first. Very cheap fix.

Here's a video of Kent talking about it:

PS, your set up is sick AF!

AF means as fruitloops for you gents not up on the lingo :p
 
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