Recharging 12v battery

[Writerman]

I just had the MCU memory chip replaced in my 2016 Model S by a third party service provider. Now, my car is saying "12v battery must be replaced soon" and some functions (Summon) aren't working.

Is this likely to be associated with the MCU chip replacement? The engineer told me the 12v battery would not be receiving charge while he worked on the MCU but everything seemed fine when he reconnected at the end of the job.

Is it worth trying to connect a smart charger to the 12v? My smart charger claims to be able to recondition batteries (and did so very effectively in my wife's Prius). If so, do I need to disconnect the battery prior to charging or is it OK just to connect and go? I've not looked yet but I'm hoping the battery terminals are easy to find but any advise in that department would be welcomed.

 

[MXLRplus]

You might consider one of the cigar lighter chargers.

I have a device that plugs into cigar lighters that tells me what voltage the 12v system is running at. For MX = 12.6v when car is asleep, 13.8v when car is awake. 10.9v is dipping into the permanent damage zone for AGMs.

I also have a 12v cigar solar maintainer but that is used for long term outside storage of cars/trucks. I don't thick it would be effective on a Tesla since the phantom drain is really high.

 

[HH525]

How long did the replacement take?