12V battery died, SOH and SOC messed up after replacing 12V

[docj]

There isn't much slack in the cables but it might work.

Why would you want to do that?

 

[Jbechtold]

GM - facing a failing (2nd/non-OEM) 12v on my 2012: Is it preferred - so as not to confuse the EMS, cause relearning, etc - to "jumper" the 12v leads with a small external cell during the exchange? E.g. just keep continuous 12v to the hot and gnd, safely of course, during the main battery swap?

I've done it for years on picky BMW's that otherwise want to be reacquainted with their new battery at the stealership - and it seemed sensible practice on these non-ICE/highly-computerized vehicles as well....?

Remember, Leafs do not fully charge the 12v battery, ALWAYS leading to premature failure.