Excellent article Jeju. Here is an example of extensive cell testing showing different energy provided at different power levels:http://www.candlepowerforums.com/vb/showthread.php?423413-Test-review-of-AW-17500-1100mAh-(Black)-2016
This is just an example of LiIon cell chemistry (Soul EV is different chemistry but should behave in a very similar way). In particular discharge energy chart:
0.2A = 4.2 Wh (approximate from reading chart)
3A = 3.7 Wh
So at 2.7C in this test we get 12% less energy
(again these are approximate from chart)
In summer easy driving will pull around 13 kW which is 0.43C so we get almost max energy output. In winter if you start pulling say 20 kW (snow/wind increased resistance, heating, etc.) now it is 0.7C
Keep in mind during acceleration we pull 1C - 2C
This is another reason (besides increased air resistance at higher speed) why range drops at higher speeds.
Back to balancing,
From the LiIon forums indeed there are discussions about individual cells going out of balance in a pack, especially 4+ cell flashlights. Couple of factors to consider:
- high quality cells (example Eneloop) will have a very consistent performance and will be less out of balance
- new cells will be more consistent, less out of balance
- best way to balance is a slow charge
Here is my interpretation of the best rules to follow based on these factors and stuff I read on forums:
1) for a new pack/car (less than 50K) cells should remain fairly balanced most of the time
2) for older packs (over 80K) increased internal resistance differences for different cells will cause more balancing issues more often
3) so new pack needs less frequent balancing, older more frequent balancing
To balance as pointed above:
Repeat 2-4 times:
1) Level 2 to 90%
2) Level 1 from 90% to 100%
Important point is that you don't need to worry about balancing too much until your car is older, especially when not going below 30% SOC. Even if a particular cell is lower than others at 30% SOC it means it may be 25% or 20% or even 15% which is still fine.
Thanks for the reminder when Level 1 is still useful as other posts were talking about Level 1 being useless and wasteful.