W176 A160 2017 Whiteart Main Battery Replacement Help Requested

[MercMikeUK]

Hi there all, I’m wondering if a genius can help me with the below:
I have a 2017 Mercedes A160 Whiteart Executive Edition with the AMG pack, fully loaded with extras. The Eco/Start stop has stopped working and I've checked the main battery (as no aux battery on this vehicle). After putting a meter on the battery it is only holding at 12.2V and goes down as low as 11.3V under load so I have been advised to replace the battery. The only issue is that Mercedes say that it has a Battery Management System and that it needs to be reset when the new battery has been installed to tell the Management System not to overcharge the new battery. Now that sounds plausible as it is an AGM battery A0019828108 VARTA original Merc battery that's installed and the terminals do have sensors on them, but when using a Icarsoft MB V2 diag tool the BMS reset is not available, which would suggest that there is not a fully fledged BMS system installed. I have confirmed that the diag tool does have the correct software, both Merc and Smart software for that vehicle and it does show all the other options it should when plugged inot the OBD2 port under the drivers side foot well. I spoke to Varta Germany and they cross refrenced the original battery to be 580901080D852 of which I have purchased, but I am reluctant to change it out due to the concern my local Mercedes Service guys put to me.

Can anyone advise?

Best wishes

 

[Blobcat]

Hello and welcome

First thing I’d do with your battery is take the cell caps off and top them up. It’s a tad challenging to get them off but it is possible. The cells in AGM’s go dry between 3 and 5 years, top them up and they miraculously recover.

 

[MercMikeUK]

Many thanks Bobcat, is it deionised water that’s needed? I know they are LA so I assume so.
thanks again for your reply, very much appreciated

 

[Tony Dyson]

Many thanks Bobcat, is it deionised water that’s needed? I know they are LA so I assume so.
thanks again for your reply, very much appreciated

Either a de-ionised solution used as a top up or if the battery is completely depleted, a replacement premix battery acid solution, with a battery holding at 12.2v I would just be topping up, only use de-ionised water for top ups in an AGM battery.

 

[MercMikeUK]

Thanks Tony, I’ll give it a try and see what happens, Instill need to find out about the BMS system in case it doesn’t work or for when I do need to swap out the battery. Thanks again for your help, it’s very much appreciated

 

[Tony Dyson]

You're welcome and if you fill in the details of your profile with a location, I'm sure members will be able to advise the nearest MB Indy who will be able to reset the battery to new with Star/xentry.

 

[MercMikeUK]

Hi Tony, thanks again and I’m in Berkshire RG12