Submariner1
Senior Member
- Joined
- Sep 3, 2016
- Messages
- 4,694
- Reaction score
- 788
- Location
- Windsor Berkshire
- Your Mercedes
- CL500 2009 5.5
some may remember the mare I had with my recent new CL Battery .... basically it passed the Mobilo attery test on 4 call outs, and then thankfully refused to start on the 4th call out and failed the test ... shorting cells or something!
So MB replaced it.
Pretty much the same crap on this battery, wont hold a charge. Charge it fully, and the next day its at 12.6V .... which over the last 4 months has dropped to 12.4V.
The ususal charge cycle:-
Charge it for 10 hours till the CTEK went into “care mode”, and the Battery is at 13.1V leave it 2 days and its was at 12.5V
Note in this, what I call a full charge cycle, the CTEK would output up to 14.9V and 3.59A until fully charged, then drop down to 13.1V in care mode with say 700mA current.
Recently since my op. The car was not driven for 20 days. And the battery was at 12.2V. To be expected. Moving her in the driveway .. so 3 starts . She started fine.
Put her on charge ... expecting at least 8 to 10 hours to get her fully charged .
Oddly I noticed after about 1 hour she was staying at about 12.9V ... and 3.2A , by then she would normally be at 14.6V to 14.9V. And rise to 3.59A ( the Cteks max.).
Then blow me in 4 hours I noticed she was in “Care Mode” at 12.8V and 870mA! Not the normal 13.1V.
So left for 4 more hours and disconnected ... next day she was only at 12.2V!
I tried the CTEK on the wifes A Class battery, ok its only a 70AH battery not 95AH, that was at 12.6V and within 30 mins it was pumping out 14.2 V. As I expected the Ctek woukd behave.
To me this all spells its another of these dam defective MB batteries. But could it be the Ctek?
To my mind, if the CTEK works as it should on the A Class battery; but does not produce more than 13.1V on the CL it smacks of something like a high or low resistance in the CL Battery tricking the CTek into thinking its fully charged, and thus making it go into Care Mode; or this naff battery just wont take more than 12.9V.
Any ideas?
Note the CL Alternator produced 14.3V at tickoover, or 14.9V at the start of a short journey as it should.
This battery has been tested 3 times by Mobilo and once by the main dealer .. passed every time.
Last month the battery reg. was also tested by the dealer, when ot was in for the wheel sensors at no charge.
They confirmed the battery drain fluctuated between a few short peaks of 40mA and 2 mA. All within spec as they say my CLs config. Could happily be up to 60 to 65mA
So no battery drsin issues imo.
Mobilo also tested the drain and once shut down found 20mA.
So before I go balistic on Mercedes, do you think it could be the Ctek charger?
I guess you can feel from the tone of the post, I think its effing disgraceful, Mercedes refuse to change a battery without you paying for it to be tested .... where the test costs more than the battery! To me thats no warranty at all.
Or should I just leave her until, she fails to start and call out Mobilo, until “they” realise its costing them a dam site more in call outs than the cost of 3 batteries?
TBH I am a tad surprised she started 3 times at only 12.2Vs.
Note so far she always manages to start ... so does it matter!
So MB replaced it.
Pretty much the same crap on this battery, wont hold a charge. Charge it fully, and the next day its at 12.6V .... which over the last 4 months has dropped to 12.4V.
The ususal charge cycle:-
Charge it for 10 hours till the CTEK went into “care mode”, and the Battery is at 13.1V leave it 2 days and its was at 12.5V
Note in this, what I call a full charge cycle, the CTEK would output up to 14.9V and 3.59A until fully charged, then drop down to 13.1V in care mode with say 700mA current.
Recently since my op. The car was not driven for 20 days. And the battery was at 12.2V. To be expected. Moving her in the driveway .. so 3 starts . She started fine.
Put her on charge ... expecting at least 8 to 10 hours to get her fully charged .
Oddly I noticed after about 1 hour she was staying at about 12.9V ... and 3.2A , by then she would normally be at 14.6V to 14.9V. And rise to 3.59A ( the Cteks max.).
Then blow me in 4 hours I noticed she was in “Care Mode” at 12.8V and 870mA! Not the normal 13.1V.
So left for 4 more hours and disconnected ... next day she was only at 12.2V!
I tried the CTEK on the wifes A Class battery, ok its only a 70AH battery not 95AH, that was at 12.6V and within 30 mins it was pumping out 14.2 V. As I expected the Ctek woukd behave.
To me this all spells its another of these dam defective MB batteries. But could it be the Ctek?
To my mind, if the CTEK works as it should on the A Class battery; but does not produce more than 13.1V on the CL it smacks of something like a high or low resistance in the CL Battery tricking the CTek into thinking its fully charged, and thus making it go into Care Mode; or this naff battery just wont take more than 12.9V.
Any ideas?
Note the CL Alternator produced 14.3V at tickoover, or 14.9V at the start of a short journey as it should.
This battery has been tested 3 times by Mobilo and once by the main dealer .. passed every time.
Last month the battery reg. was also tested by the dealer, when ot was in for the wheel sensors at no charge.
They confirmed the battery drain fluctuated between a few short peaks of 40mA and 2 mA. All within spec as they say my CLs config. Could happily be up to 60 to 65mA
So no battery drsin issues imo.
Mobilo also tested the drain and once shut down found 20mA.
So before I go balistic on Mercedes, do you think it could be the Ctek charger?
I guess you can feel from the tone of the post, I think its effing disgraceful, Mercedes refuse to change a battery without you paying for it to be tested .... where the test costs more than the battery! To me thats no warranty at all.
Or should I just leave her until, she fails to start and call out Mobilo, until “they” realise its costing them a dam site more in call outs than the cost of 3 batteries?
TBH I am a tad surprised she started 3 times at only 12.2Vs.
Note so far she always manages to start ... so does it matter!
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