Battery or alternator issue
Thread Starter
Newbie
Joined: Nov 2025
Posts: 1
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2011amg s63
Battery or alternator issue
My battery was dead, so I took it to AutoZone and they charged it for me once I installed it. I went back so they can check the battery and the alternator. They stated that the alternator was charging, but the battery was only at 60% when they charged it It was at 100% it. I only drove half a mile right back to AutoZone and it drained half the battery. Can this be an electrical shortage?
Senior Member
Joined: Oct 2011
Posts: 320
Likes: 185
From: Philadelphia
2002 CLK55 AMG: 2004 S55 AMG: 2009 C63
"Access the secret HVAC menu by turning the key to position two. Make sure your climate control is on and just turn the fan down to low. Then hold the "Rest" button in until you see the menu pop up on the screen. Using the Driver side up/down hot/cold arrows, scroll up (about 24 times) until you get to NR.24 which will show you your current battery voltage. You can then turn the car on and the screen will stay. Turn your fan on high and cut the wheel back and forth and see how much voltage your dropping, if any. It will also tell you if your alternator is charging properly by a spike from the car being off to turning it on and running."
Copied from a previous post.
Good luck
- Joe
Copied from a previous post.
Good luck
- Joe
Member
Joined: Nov 2025
Posts: 85
Likes: 3
From: Taiwan
W212 E63 AMG
My battery was dead, so I took it to AutoZone and they charged it for me once I installed it. I went back so they can check the battery and the alternator. They stated that the alternator was charging, but the battery was only at 60% when they charged it It was at 100% it. I only drove half a mile right back to AutoZone and it drained half the battery. Can this be an electrical shortage?
Member
Joined: Nov 2016
Posts: 160
Likes: 46
S-65 AMG
"Access the secret HVAC menu by turning the key to position two. Make sure your climate control is on and just turn the fan down to low. Then hold the "Rest" button in until you see the menu pop up on the screen. Using the Driver side up/down hot/cold arrows, scroll up (about 24 times) until you get to NR.24 which will show you your current battery voltage. You can then turn the car on and the screen will stay. Turn your fan on high and cut the wheel back and forth and see how much voltage your dropping, if any. It will also tell you if your alternator is charging properly by a spike from the car being off to turning it on and running."
Copied from a previous post.
Good luck
- Joe
Copied from a previous post.
Good luck
- Joe
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Senior Member
Joined: Oct 2011
Posts: 320
Likes: 185
From: Philadelphia
2002 CLK55 AMG: 2004 S55 AMG: 2009 C63
2010 is a w221, so wrong forum. However yes it is accurate. Only way for us 220 guys to see hidden information not displayed in the cluster/infotainment.
- Joe
- Joe
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