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As above
i own a 2014 cla220 cdi amg sport, owned it since feb this year and love the beast, when i 1st purchased it the dealer fitted a new battery for me as the original was not holding its charge very well, must confess i did not look at what they fitted, checked the battery voltage today while i was fitting a blackvue dashcam and the voltage seemed rather low, (car has been sat since saturday doing nothing)
so my question is what size/spec battery should i have on the car?
if the car has been sat for 2 days doing nothing what would you expect the voltage to be? mine was just over 12v, when i started the engine the reading was over 14v

cheers

oh by the way 1st post please be gentle :)
 

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voltage seemed rather low, (car has been sat since saturday doing nothing)
so my question is what size/spec battery should i have on the car?
if the car has been sat for 2 days doing nothing what would you expect the voltage to be? mine was just over 12v, when i started the engine the reading was over 14v
oh by the way 1st post please be gentle :)
Your CLA is constantly using battery power when the engine is not running, so I see no cause for concern. Another UK owner may be able to post a picture of his 220 battery for you.
No need to be gentle...you have started many good subjects here, but as one gets older, he tends to be forgetful.
 

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ummm … errr … there are parasitic drains when static on the order if 250mAh (like mine) depending on the telematics
that said a good battery with high soc (state of charge) can sustain a few days etc etc
Then as it ages the soc attainable drops as the chemistry ages with time and drains
12.6v static (2.1v per cell, 6 cells) after a couple days is fine … though the soc will show signs of aging when it starts to drop (so get good calibrated meter and use the same scale when tracking day to day)
 

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Circa 14.4V is the charging voltage from the alternator.

You need to put more voltage in to charge it.

Sitting idle 12.6V as said is fully charged but this will drop off after a while. Don't worry about it
 
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