2011 c300 battery drain
12-05-2016, 06:13 PM
#1
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c300
2011 c300 battery drain
Have a 2011 c300. The OEM battery died recently and it killed the alternator too. I replaced the alternator and along with it a new battery. I have been noticing that the car draws a large current
When i look at the vehicle data menu i get the following when the car is running:
VB: ranges from 13.1 - 14.6 v
IB: at start its around 35A and than reduces to 5-6A during the drive
Does c300 draw 35A current ?
The big issues is my battery voltage seems to drop over night. After a long drive my battery shows a full charge of 12.6v and than the next day it shows 12.0v. Is this normal ?
When i look at the vehicle data menu i get the following when the car is running:
VB: ranges from 13.1 - 14.6 v
IB: at start its around 35A and than reduces to 5-6A during the drive
Does c300 draw 35A current ?
The big issues is my battery voltage seems to drop over night. After a long drive my battery shows a full charge of 12.6v and than the next day it shows 12.0v. Is this normal ?
12-06-2016, 02:49 PM
#2
MBWorld Fanatic!
Have a 2011 c300. The OEM battery died recently and it killed the alternator too. I replaced the alternator and along with it a new battery. I have been noticing that the car draws a large current
When i look at the vehicle data menu i get the following when the car is running:
VB: ranges from 13.1 - 14.6 v
IB: at start its around 35A and than reduces to 5-6A during the drive
Does c300 draw 35A current ?
The big issues is my battery voltage seems to drop over night. After a long drive my battery shows a full charge of 12.6v and than the next day it shows 12.0v. Is this normal ?
When i look at the vehicle data menu i get the following when the car is running:
VB: ranges from 13.1 - 14.6 v
IB: at start its around 35A and than reduces to 5-6A during the drive
Does c300 draw 35A current ?
The big issues is my battery voltage seems to drop over night. After a long drive my battery shows a full charge of 12.6v and than the next day it shows 12.0v. Is this normal ?
Before starting Volts 12.1, Amps 33
Whilst starting volts around 10, amps 102.The starter draws a lot which is normal.
Idling Volts 14, Amps 33 & reducing to 13 amps over about 3 minutes.After 15 minutes driving the amps were 5.9.
I say that your system is completely normal. My system was 12.4 V after a run & 12.1V in the morning.
I must say I am surprised of the high 33 amp load with just the key in the ignition .
Why does the load slowly decline from 33 to 6 odd amps over 15 minutes?
Any auto electrical engineers out there ?
Last edited by Carsy; 12-06-2016 at 07:55 PM.
12-08-2016, 01:44 AM
#3
12.1 v before start seems low - should be close to 12.6 if charged properly the previous day.
First step would be take battery to auto parts. Shop and get it load tested
if alternator is running you should see around 13.5v to 14v at battery
if not have alternator testwd
But even if alternator is charging you could have bad diodes that are causing battery drain when off - so make sure those are tested
you then need to check all cable connections between alt and bat are tight and clean - ground strap too.
if all that is good - then you need to test every fuse for current drain (auto electrician can do that or it is quite easy with multimeter and appropriate adapter) - when ignition is off .
First step would be take battery to auto parts. Shop and get it load tested
if alternator is running you should see around 13.5v to 14v at battery
if not have alternator testwd
But even if alternator is charging you could have bad diodes that are causing battery drain when off - so make sure those are tested
you then need to check all cable connections between alt and bat are tight and clean - ground strap too.
if all that is good - then you need to test every fuse for current drain (auto electrician can do that or it is quite easy with multimeter and appropriate adapter) - when ignition is off .
12-08-2016, 04:14 AM
#4
MBWorld Fanatic!
12.1 v before start seems low - should be close to 12.6 if charged properly the previous day.
First step would be take battery to auto parts. Shop and get it load tested
if alternator is running you should see around 13.5v to 14v at battery
if not have alternator testwd
But even if alternator is charging you could have bad diodes that are causing battery drain when off - so make sure those are tested
you then need to check all cable connections between alt and bat are tight and clean - ground strap too.
if all that is good - then you need to test every fuse for current drain (auto electrician can do that or it is quite easy with multimeter and appropriate adapter) - when ignition is off .
First step would be take battery to auto parts. Shop and get it load tested
if alternator is running you should see around 13.5v to 14v at battery
if not have alternator testwd
But even if alternator is charging you could have bad diodes that are causing battery drain when off - so make sure those are tested
you then need to check all cable connections between alt and bat are tight and clean - ground strap too.
if all that is good - then you need to test every fuse for current drain (auto electrician can do that or it is quite easy with multimeter and appropriate adapter) - when ignition is off .
