Voltage drops on acceleration - Mercedes-Benz Forum

 
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post #1 of 8 (permalink) Old 10-14-2014, 11:00 AM Thread Starter
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Voltage drops on acceleration

I am troubleshooting charging in my 77 280SE. What confuses me is that when there is acceleration the voltage output drops?

Anyone know what might cause this, to go from 12.8 to 11.7 when accelerating?

Thanks!
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post #2 of 8 (permalink) Old 10-14-2014, 01:46 PM
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Bad regulator, eh?

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post #3 of 8 (permalink) Old 10-14-2014, 03:36 PM
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Does it also change with the addition of load to the system (turn on high beams and blinker). If yes, I would lean toward regulator.

Does this year have the regulator integrated with the brushes in the alternator? Worn brushes could "float" with the increased rpm of the alternator causing the drop in voltage.
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post #4 of 8 (permalink) Old 10-14-2014, 05:58 PM Thread Starter
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Bad regulator, eh?
Where is the regulator? Thanks for the reply.
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post #5 of 8 (permalink) Old 10-14-2014, 06:40 PM
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I believe the regulator is build into the alternator. So you must replace the alternator. Smarter minds will chime in wilh a more definite answer.
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post #6 of 8 (permalink) Old 10-15-2014, 08:43 AM
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loose belt ???? .the regulator is at rear of alternator , 2 screws , easy to replace on car .
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post #7 of 8 (permalink) Old 10-17-2014, 07:12 AM
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Where is the regulator? Thanks for the reply.
This is the regulator, it's on the back of the alternator.

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Alternators are reasonable, too, plus they come with the regulator included.

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post #8 of 8 (permalink) Old 10-17-2014, 09:14 AM
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if the brushes on alternator are worn and not making contact , the alternator light will not come on when turning ignition on .
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