Low 12V battery warning
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W206
Low 12V battery warning
What should be the optimal resting voltage of the 12V battery on GLB35? Is 12.6V the cutoff? I got a critical 12V battery warning from Mercedes Me and said I need to drive it for 30 to 60 minutes continuously. So I took it out on a back road and did some spirited driving for 30 minutes. Now the resting voltage reads 12.34V on a multimeter. Should I get an AC charger and put it on charge? Thanks.
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
Battery voltage is somewhat temperature dependent. It’s winter, so voltage could be lower. What’s the temperature where the battery has been sitting?
Thread Starter
Junior Member
Joined: Sep 2019
Posts: 35
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W206
MBWorld Fanatic!
Joined: Sep 2013
Posts: 2,346
Likes: 692
2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
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Saab
You may have done this, but if your car is going to sit for at least seven or more days, you can activate Standby Mode. You can find in MBUX under the Settings -> Vehicle menu. It is suppose to help save your battery if the car is expected to sit.
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From: SWW WA USA
21 GLB35 07 E550 Sport
IMHO yes. Portland area '21 GLB 35 owner. A week or so before the cold weather hit us the MMe service was informing me of the critical status of the battery, the day before snowmaggedon I picked up my E550 from a service (and a new battery for it, it was time) and bought an MB 5A trickle charger. I connected the charger to the GLB and it showed an "OK" status (green light) but with a 50% charge level and IMHO the most important status - the "Fault" indicator was not illuminated. I left the charger connected for 8 days while the weather was in the teens and 20s, it took 5 days to get to 75% status and on day 9 the charger indicated a 100% charge and I disconnected it. The error messages were being sent out while the garage was in generally in the upper 40s to lower 50s.
Two days ago I drove the GLB about 125 miles and yesterday about 40 miles. Out of curiosity I hooked up the charger a couple of hours ago and the charge status showed an amber color at 50%, it's still amber but now at 75%. The temp in the garage is again in the mid-40s. The Fault light is still not illuminated. My takeaway from this is that I'm aware the GLB's battery is just over 3 years old and the system isn't charging it fully - it's due for a B1 service in the next couple of weeks and, despite not showing a Fault I'm going to have a new battery installed and not wait for a fault to leave me stranded. Do look into getting an MB trickle charger, my 2¢.
Two days ago I drove the GLB about 125 miles and yesterday about 40 miles. Out of curiosity I hooked up the charger a couple of hours ago and the charge status showed an amber color at 50%, it's still amber but now at 75%. The temp in the garage is again in the mid-40s. The Fault light is still not illuminated. My takeaway from this is that I'm aware the GLB's battery is just over 3 years old and the system isn't charging it fully - it's due for a B1 service in the next couple of weeks and, despite not showing a Fault I'm going to have a new battery installed and not wait for a fault to leave me stranded. Do look into getting an MB trickle charger, my 2¢.
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2013 glk 350
9 days on a charger at 5a to go from 50-100%? Did you test for phantom load draw? Or maybe the charger doesn’t work right . You could test the charger or try it on another vehicle. 9 days is too long to charge . Has battery been tested? AGM last 6-9 years when taken care of. My 13 is on its second battery and it tests fine. I can understand a day to charge , but not 9!
