I'm posting this here too just in case there are no electricians lurking about over on vintage.

Will installing a 65A regulator on a W123 55A alternator increase the amperage output, or does the alternator itself need to be changed to gain the increase?

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Don't Chrome them; polish them

I'm pretty sure the stator and rotor would have to be changed to make it pump out mare amps.

Are you having issues with the stock unit?

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"I was a dirty bird, Carol's not grungey - she's *****in" John Milner....American Graffiti

None at all. It's just that I have noticed that regulators for sale state for 65a alternators even though they are the same regulators that go on the older models. Apparently the rear of the armature is the same diameter on the 55a and 65a alternators.

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Don't Chrome them; polish them

I think you are right about the armature.

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"I was a dirty bird, Carol's not grungey - she's *****in" John Milner....American Graffiti

I'm not an electrician, but I'm pretty sure that's not how it works. A voltage regulator is supposed to maintain a constant voltage level for the design of the alterntor, there is no way it could "increase" the output, I don't think. Or everyone would be swapping regulators instead of entirely new alternators.

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1991 300E - 212K and rising fast...

throw a newer one on there..

110-143 amp or the 150 amp up to 2000 or 2001. Not a big deal...

very correct . the regulator simply maintains the voltage at around 14V and cuts of when the battery reaches 14V ,a Full charg condition.
A faulty regulator may not achieve full charging voltage or it may overcharge and blow the OVP fuse.

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mark

M110s use pretty different brackets (v-belts) than what the 110-143A units do.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
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Six others from BMW, GM, and Ford.

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if you run a battery down till its dead then jump start the battery can this cause damage to the regulater on the alternator causing it to drop volts to 12.65 under a load,i just installed a new raman bosch alt and it appears its defective i wonder if a new regulator would help,any ideas?

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A rebuilt alternator is already going to have a new regulator/brushes - or it should have if the rebuilder has even an ounce of decency - so I doubt that putting on another alternator will help, unless you ran down the battery with the new alternator.

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you mean replacing the regulator wont help,yeah its a fully refurbished factory 65axl alt with all new everything,but it just went defective only putting out 12.65 v under a load,i wasnt sure if maybe the regulator was defective,id much rather replace a regulator than the alternator again,i had to replace this alt with the belt still on tight ,took me 3 hours,i was not able to figure out how to loosen up the upper bolt to pivot the tensioner,i was able to loosen up the lower bolt/rod that goes to the tensioner thats it,i couldnt get a socket or attachment to fit the upper bolt in the bracket.

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enjoy life,take the coal that is handed to you and turn it into diamonds. { PHILLIPIANS 4:13}

Where are you connecting your meter to measure the load?

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i had the meter on the top of the pos and neg posts on the battery.

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enjoy life,take the coal that is handed to you and turn it into diamonds. { PHILLIPIANS 4:13}