Weird SOC activity

For the past month or so, the SOC has been jumping around quite a bit. I know this is normally indicative of impending traction battery failure (and so is the 205k on the odometer). Well, today it happened. The dash panel lit up like a christmas tree. Drove it home with no loss of performance. No loss of efficiency, either (avg 45 mpg, but it always averages lower in the winter/spring months).

I pulled the +12Vdc line off of the aux battery and let it sit a few minutes. When I reapplied power and started the car, no warning lights. In fact, the SOC meter is now behaving normally. I went for a 15 mile, half hour drive and noticed no difference in performance other than a) the SOC meter is now behaving more like I expect and B ) the car turns the ICE off more. MPG average for this drive was 49.2 mpg, and it was a combo of city and highway.

I did floor it for a good 15 seconds while merging onto the highway and the SOC meter dropped to 1 bar before rising to and maintaining 6.

I checked the inverter fluid and the pump seems to be functioning. The aux battery (yellow top) was purchased 2 years ago.

I guess my question is, is this actually an impending traction battery failure? If so, I suppose I should order a few cells in the near future.

 

It was probably closer to 10 seconds (to roughly 65 mph). Wasn't timing it.

The gen 3 modules are drop ins? What would be the advantage (other than that they are "new")? Really not looking to spend $1500 right now, we're trying to move this summer.

 

$2200 for brand new (MSRP minus core credit) or $1500 for one with uncertainty. I drive about 700 miles a week, it might be better to eat the extra $700 for peace of mind.