Hey everyone, yet again another 211 battery problem. In May of this year I replaced the aux battery, rear battery (oem) and the (oem) alternator. All was well, but I have noticed that after 2 days or more of sitting the red battery light comes on, granted it’s kind of cold here in the 50’s. After driving the car and cycling the keyes it charges up and goes away. The car non started voltage after sitting a day is 12.2 and idling is 14.0 so that seems fine. As of now I have hooked the main battery to a 12v trickle charger to see if it does anything. Will plan to drive it later today or tmre.

 

You have a bad module that is not going to sleep and it is draining your battery. Multiple posts on this or you can consult WIS. You're going to have to take it from here....

 

so I just have to start it daily so it doesn’t drain? That’s okay?

 

[QUOTE=AMG__POWER;7933733I have noticed that after 2 days or more of sitting the red battery light comes on, g[/QUOTE]

Check the battery voltage after 2 days, and see what it is. 11.9-12.1 V should be fine. Look at the voltage while cranking. 10V and above is OK. Where did you get the alternator?

 

yeah it’s usually in that range; the alternator is oem mercedes

 

Update- whilst cranking, 10.8, idling 14.0.
sos and teleaid took a dump tho