JoeS wrote:So, why the rigmarole the dealers subjected some of our members to in order to measure capacity (e.g., charge fully and drain battery using heater), not to mention a dealer telling me they couldn't do it?
Malm, since you have a good handle on this, how do your EVBatMon (CAN) numbers compare with various other techniques for determining capacity? Incidentally, wish you all the best in getting Mitsubishi to replace your degraded (but not broken) pack. The magic number for Leaf and Kia, IIRC, is 30% capacity loss; i.e., down to 70% of original capacity.
Determining capacity by discharging it to 20% and then charging it to 100%, in my opinion, doesn´t work. Why? 1 - Because SoC can sometimes jump for another number in a millisecond. 2 - Because 20% of SoC can be 35% of real charge of the battery (specially in a new car, at this stage the car can stop at 0,0% SoC with still 3,6 V in the weakest cell), at 0,0% SoC the car will be 15% full. 3 - A 100% charge is not always to 100% full, sometimes the charge stops at 359/360 total voltage, and not at 361V.
Before I had EvBatMon I had my own method. See the voltage at 0,0% SoC by Canion and how much was a bar of 5% in energy (50-55%) when charging. If the car can go to 0,0% SoC and one bar of 5% is about 630 Wh, then I think the car has a range of a new one and the remaining capacity will be over something like 42 Ah. I tested some second hand i-MiEVs for some of my friends with this method and it worked well.
For me, the best way to know the capacity in an i-MiEV is this number given by the EvBatMon. Yes, it can be not very well calculated in a old battery with cells much with more degradation then the others (I agree with zzcoopej).
Riding an i-Miev since 4/2011 in Portugal, 100.000 kms.