Increased battery range after service for check engine light

[Lonewarrior]

The two coldest days we've had so far this year. First occurrence, cold soak, overnight early morning temp was 29F, but low 30's by the time I launched (after pre-heating with lvl 2 plugged in) and likely mid to high 30's at onset of cautions.

It made a re-appearance this past Sunday after an overnight/early morning temp of 23F, in this case, a few hours away from home overnight outside in the driveway plugged into lvl 1 at my son's house. We were babysitting a grandson and fairly early in the morning I unplugged and moved it out into the cul-de-sac in the sunshine. Pre-warmed on battery before departing in the early afternoon and got a recurrence of the HV batt codes and simultaneous "power system" caution 240 miles after the first occurrence. It was probably about mid-30's again at onset of the problem. Again, running in HV/Sport at onset, about 55-60 mph steady state.

Cleared codes, re-charged. Took it to town and back in sport, all EV operation, and actual miles driven were 80% of EV miles depleted.
No codes, but it was warmish today, low to mid 60's.

The code appeared as a result of the pre-warming. A cold and older battery charges more slowly, and when pre-warming begins it immediately places a heavy demand on an already weaker pack, causing the vehicle to draw power from the charging station at its maximum rate. That in return triggered something the BMS didn't like.

Next time, take a look at the charging speed when the battery is cold and observe what happens to the charging power when the climate control is activated. I’ve seen many instances where charging power was limited to around 4 kW due to low temperatures, only to surge immediately to 7 kW (maximum power) once the climate control was turned on.

I don’t believe this indicates any harm to the car; rather, it’s simply the vehicle signaling that the battery pack is aging.