Got this advisory when PCM didnt come on “PCM unavailable due to low battery voltage.” 350 miles on the car and some time on battery power configuring homelink etc. But also several hours on battery tender ((Li specific for the Li battery). Is this normal? Drove car about 35 miles since, Battery indicated 13.4V after that. I know Li battery cars have their quirks, but this is ridiculous.

 

It could take more than a few hours on a battery tender to reach a full charge.
Thirty-five miles of driving is probably not enough to fully charge.
Does the tender indicate the state of charge? Mine gives a percentage.

 

I figured that, but the battery had to be fully charged from my 250 mile trip the pervious day. Maybe 1/2 hour with PCM doing configuration on battery. 3 hours on charger …CTEK just lights, not %. It would appear the Li battery will lose its charge rather quickly if left to power the car w/o engine running.

 

From RL anecdotal evidence only, it is quite possible that 30 minutes setting up the PCM is enough draw to cause an issue. I would keep it on the CTEK when not driving it for the next couple of days and hope it does not reoccur.