Yesterday I figured out that my battery is bad. I don’t know when it happened but it was sometime between March and August. In March we did a trip to the desert and the battery behaved as expected in both discharge (range) and charging at fast chargers.
Then over the summer I noticed that the range went to shits. 140 miles on a full charge; not the GoM though .. the GoM still thinks I have 230 miles even though I have been proving it wrong every day.
I started keeping track of all trips in August.
I thought that it was my driving. I kept track of kWh SoC as provided by WattCat. Indeed, I was churning through tremendous kWh, and the SoC *percentage* as reported by the car matched the kWh. [I calculated the correlation, WattCat’s kWh SoC correlates with car-reported SoC %age at R-squared of >0.99. There's a plot in another post.]
My consumption, even on totally benign, not-pushing-it, trips has been insanely high, by both reported SoC %age and kWh.
Yesterday I used a fast charger for the first time since March because I went up to the mountains and had to charge. I used it twice, once on the way up and once on the way down.
Here are the kWh added as reported by the charger (first number); the difference in kWh pre- and post-charging as reported by WattCat (second number); and the difference in percentage SoC pre- and post-charging as reported by the car (third number).
31.9 58.1 69%
38.7 63.7 74%
So: assuming no loss from the fast charger, my total battery capacity is:
31.9 kWh / 0.69 = 46.2 kWh
38.7 kWh / 0.74 = 52.3 kWh
(If you consider ~3% or so loss it's even worse)
And last night I did the same with my L2 charging cable, same story.
So: in contrast to
(see the WattCat thread, page 4), in my case both the reported SoC %age *and* the reported kWh SoC is erroneous. (Not WattCat's fault, obviously, but the car's because it reports an incorrect value).
How is it possible that the car doesn’t report an error when the issue is this extreme?!?