I replaced the battery just over two years ago, properly coded in by the installer.  My car is a 2014 CR140 with Stop Start, the battery fitted was a decent Varta E39 (I think) AGM suitable for the car, 4 year guarantee I think...

 

With lockdown and working from home I have been using the car a lot less, so it isn't getting run/charged as much as it normally would.

With the current cold snap cranking is a bit sluggish and I wondered about giving it a full re-charge with a CTEK smart charger which has the correct AGM charging mode.

 

I know some smart charger manufacturers say they can be fitted while the battery is in situ and connected but I fear this will damage the electronics.  Disconnecting the battery seems the sensible approach, negative off first, then positive then connect up the charger.  I believe radio coding shouldn't be an issue while the battery is disconnected from replies to my original post a couple of years ago.

 

I would appreciate any advice on the best approach for charging in this type of scenario.

Cheers

Dave

Edited 2 January, 20215 yr by TasMan

To @TasMan - On mine "Skoda Superb 2 Face Lift Combi, 2014, 2.0TDI, 170ps, 4х4, 6DSG" with "AGM" battery I use "Ctek" charger too but do not disconnect the battery from Car. My battery is still original from the Car factory and I expect a failure soon :( I give it charge once a mount. There is no Problem with electric of the Car..

I use a AA trickle charger and don't disconnect , but clip the negative lead to the Tag above the terminal on my Karoq.

The service manual says an AGM battery can be charged while connected to the vehicle but the negative connection of the charger should be connected to an earth point on the body rather than directly to the battery's negative terminal.

 

Quote

On vehicles with the “start-stop” system and with the battery
monitoring control unit - J367- installed, the “-”-terminal (black)
of the charger must be connected to the body mass. If it is
connected directly to the negative terminal of the battery, this
can lead to the failure of the “start-stop” system after charging.

The “-” terminal (black) of the charger must be connected to
the Earth point in engine compartment in such a way as to ensure
a firm connection between the charger terminal and the
earth point (e.g. to the terminal of the earth lead of the cylinder
block or to the lifting eye of the cylinder block).

On severely discharged batteries, it can happen that on the
battery charger the charging voltage can switch over to the
nominal value of 6 V (the battery charger automatically evaluates
if it is a 6 V battery). In this case, the battery charger must
be switched over manually to charge a 12 V battery, see ⇒
Operating instructions of the battery charger .

 

Thanks for all the replies, I will have a nosy under the bonnet for the body / engine earth point and go from there.  Just wanted to be sure as a blown control module would be an expensive and bad start to my new year !!