dead battery
Thread Starter
Newbie
Joined: Feb 2018
Posts: 1
Likes: 0
300 sport 4matic
dead battery
mercedes c300 sport 4matic battery will not stay charged the auto lamp inoperative light is on. I can charge it up and as soon as I turn the car off the battery is dead again. My battery is not two years old. The sensor has been changed so what other reasons for the quick drain?
Member
Joined: May 2017
Posts: 242
Likes: 48
From: West by god Virginia
'08 C300 4Matic Sport / '11 C63
If it's dead as soon as you start it up and turn it off that sounds like a dead cell in the battery, Is yours an AGM or lead acid liquid battery?
Have you had the battery tested? Also since it has only been 2 years your battery should be under warranty and be replaced for free. Unless you went with a really crappy replacement.
Have you had the battery tested? Also since it has only been 2 years your battery should be under warranty and be replaced for free. Unless you went with a really crappy replacement.
Junior Member
Joined: Dec 2017
Posts: 19
Likes: 2
2012 C300
What kind of voltage are you getting at the battery with the car running it should be 13.8 volts or higher. If not, an alternator or voltage regulator problem.
What kind of voltage age are you getting at the battery with the car off for 20-30 minutes? If less than 12.5, you may have a shorted or dead cell in the battery.
What is the amperage draw at the battery with the engine off and car at rest? If you are getting a draw, start pulling fuses one by one to isolate what circuit the draw is coming from.
What kind of voltage age are you getting at the battery with the car off for 20-30 minutes? If less than 12.5, you may have a shorted or dead cell in the battery.
What is the amperage draw at the battery with the engine off and car at rest? If you are getting a draw, start pulling fuses one by one to isolate what circuit the draw is coming from.
