Voltage Regulator
Thread Starter
Super Member
Joined: Dec 2007
Posts: 978
Likes: 224
2005 S500 Designo
Voltage Regulator
My alternator doesn’t seem to produce power at idle, only when it’s slightly above idle. It’s possible this is an energy saving feature of the car, but I’m not sure. It could be a bad voltage regulator. These typically go between 100k and 150k. I don’t think my alternator has been replaced.
However. I can’t seem to find even an alternator for the car.
Here’s the part number from mboemparts.com: 275-150-00-50-80
Is this something that can/should be replaced? is not producing voltage at idle an indicator of a bad voltage regulator? Is the job kill yourself bad?
However. I can’t seem to find even an alternator for the car.
Here’s the part number from mboemparts.com: 275-150-00-50-80
Is this something that can/should be replaced? is not producing voltage at idle an indicator of a bad voltage regulator? Is the job kill yourself bad?
My alternator doesn’t seem to produce power at idle, only when it’s slightly above idle. It’s possible this is an energy saving feature of the car, but I’m not sure. It could be a bad voltage regulator. These typically go between 100k and 150k. I don’t think my alternator has been replaced.
However. I can’t seem to find even an alternator for the car.
Here’s the part number from mboemparts.com: 275-150-00-50-80
Is this something that can/should be replaced? is not producing voltage at idle an indicator of a bad voltage regulator? Is the job kill yourself bad?
However. I can’t seem to find even an alternator for the car.
Here’s the part number from mboemparts.com: 275-150-00-50-80
Is this something that can/should be replaced? is not producing voltage at idle an indicator of a bad voltage regulator? Is the job kill yourself bad?
Member
Joined: Jul 2019
Posts: 122
Likes: 41
2007 CL600
You should have about 14v regardless of idle or not. It may fluctuate as you rev the car because the voltage regulator needs to make adjustments to keep it as close to 14v while the rotation speed varies.
If you are not getting 14v at idle then it is almost certainly the regulator that is causing the issue. I believe the diode bridge could also be an issue. I recall reading about someone who managed to get this remedied (the watercooled alternator on the older S600/S65/CL equivalent models.) by going to an alternator refurbisher.
If you have a newer S600/S65 with the air-cooled Bosch alternator then you can only replace the regulator. The diode bridge is build into the rear housing.
If you are not getting 14v at idle then it is almost certainly the regulator that is causing the issue. I believe the diode bridge could also be an issue. I recall reading about someone who managed to get this remedied (the watercooled alternator on the older S600/S65/CL equivalent models.) by going to an alternator refurbisher.
If you have a newer S600/S65 with the air-cooled Bosch alternator then you can only replace the regulator. The diode bridge is build into the rear housing.
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Thread Starter
Super Member
Joined: Dec 2007
Posts: 978
Likes: 224
2005 S500 Designo
You should have about 14v regardless of idle or not. It may fluctuate as you rev the car because the voltage regulator needs to make adjustments to keep it as close to 14v while the rotation speed varies.
If you are not getting 14v at idle then it is almost certainly the regulator that is causing the issue. I believe the diode bridge could also be an issue. I recall reading about someone who managed to get this remedied (the watercooled alternator on the older S600/S65/CL equivalent models.) by going to an alternator refurbisher.
If you have a newer S600/S65 with the air-cooled Bosch alternator then you can only replace the regulator. The diode bridge is build into the rear housing.
If you are not getting 14v at idle then it is almost certainly the regulator that is causing the issue. I believe the diode bridge could also be an issue. I recall reading about someone who managed to get this remedied (the watercooled alternator on the older S600/S65/CL equivalent models.) by going to an alternator refurbisher.
If you have a newer S600/S65 with the air-cooled Bosch alternator then you can only replace the regulator. The diode bridge is build into the rear housing.
Member
Joined: Jul 2019
Posts: 122
Likes: 41
2007 CL600
May be possible with the newer bracket A2751550135 but I don't know how the various lines differed around on the older engine revision. My M275.953 has various oil and hydraulic lines that route around the alternator and are bolted to the bracket in various places. I also don't know how your alternator connections may differ.
Easiest option would be to just get yours refurbished, or buy a used one and send that off for a full refurbishment.
Easiest option would be to just get yours refurbished, or buy a used one and send that off for a full refurbishment.
Thread Starter
Super Member
Joined: Dec 2007
Posts: 978
Likes: 224
2005 S500 Designo
May be possible with the newer bracket A2751550135 but I don't know how the various lines differed around on the older engine revision. My M275.953 has various oil and hydraulic lines that route around the alternator and are bolted to the bracket in various places. I also don't know how your alternator connections may differ.
Easiest option would be to just get yours refurbished, or buy a used one and send that off for a full refurbishment.
Easiest option would be to just get yours refurbished, or buy a used one and send that off for a full refurbishment.
