arnis wrote:Once again I'm witnessing interesting behavior of HX and SOH values.
My vehicle is almost 3 years old. This winter, for 5 months, SOH and Hx
values were frozen, literally, near 98 99% values. Those values NEVER change
if battery doesn't heat up to at least 15C (4 temperature bars).
This year we went from snowstorms, hail, subfreezing awesome weather to
+23C (73F), absolutely sunny, in like, 2-3 weeks. As soon as pack got up to 15C
SOH and Hx values started to drop (they do that every spring). And for now,
30-35 days later after winter Hx/SOH "frozen" period, I've dropped form 99.03%
Hx and 99% SOH down to 91,08% Hx and 91% SOH.
With absolutely no change in range. Actually range is way better due to more efficient
chemistry (I stopped using heater at +5C). Went up from 120km to around 150km, same
usage scenarios, 50% at speed 100km/h, all else urban.
Both scenarios no HVAC draw, same tires, different pack temperature (5C vs 25C).
HX SOH values will start going up again in fall, and freeze for winter.
PS! If I DC charge, both values will go up for short period. This is known behavior.
As far as I understand, values creep up slowly. And the closer the battery is to the 4
temperature bar lower limit (+15C), the higher those numbers go.
Therefore those values are not good for capacity estimation.
mine change in Winter... In fact I took a new car with SOH 100, Hx 102ish and ran them down to 97/ 97.23% in slightly more than 2 weeks. Max temp during that time was in the garage in the low to mid 50's. Mostly at the upper 30's to low 40's
