Posts: 339
Joined: Wed Jan 28, 2015 1:52 pm
Location: Albuquerque NM

Re: measuring capacity loss through CanIon

Tue Nov 28, 2017 6:14 pm

matija wrote: Another thing is, how to interpret those readings. Does 35Ah versus 48Ah actually mean 27% SOH loss in my case ? Could be subjective, but I do not see 27% less daily range on this car :-) I've actually read somewhere, that with degradation, Mitsu's BMS allows different/lower voltages of cells to be utilized, hence mitigating that SOH loss in real-world. Another thing is that turtle range becomes smaller.

I do know that the car does this from all I have read and experienced. The idea, I'm certain was to instill confidence in owners. Look what happened when leaf owners saw range decreasing on relatively new cars. Tesla does this too, hides some unused capacity in the battery range calculations for down the road. So that the owners have a more congruent experience as their batteries age and rack up miles.

Actually, any ICE will get a decrease in efficiency as they wear. It's just almost impossible to notice, since the energy onboard is so plentiful. A 10 gallon gas tank would be roughly equal to ~20 iMiev batteries worth of energy. If our batteries were 20 times the energy we currently rely on, would this topic even exist?

usable battery capacity is dependent on temperature. However that shouldn't be indicative of nominal battery capacity. Most of the battery capacity measuring I'm familiar with, is temperature adjusted. Whether the Mitsu system compensates for temperature in it's measurements is an unknown. Both of our cars are showing right around 43ah on Canion. Both are 2014's built a month apart. One has twice the miles on it as the other one, for whatever that is worth? One outlier reading of 41ah among seven total. So it's not a definitive measurement IMO. Except perhaps as an average of several readings?

2014 cool silver ES, acquired new 4/2015
2014 Labrador Black Pearl ES, acquired new 3/2016

Posts: 56
Joined: Wed Apr 13, 2016 8:30 am

Re: measuring capacity loss through CanIon

Mon Dec 04, 2017 9:24 am

It looks like my car makes corrections to the Ah value twice a year. As I previously said, the Ah counter decreases my 0.1Ah every 20-something days. My car was at 39.9Ah this April, but in May it corrected to 40.8Ah. In October I was back to 40.3Ah but in November I noticed another recalculation to 41.1 Ah, which is where I'm at now. So it looks like I could count an adjustment every 6 months.
The first time I had an Ah reading was in April 2016, and it was 41.3Ah. I didn't notice any big changes in the recalculations that year, unlike this one.

Posts: 6
Joined: Sat Nov 11, 2017 10:48 am

Re: measuring capacity loss through CanIon

Mon Dec 04, 2017 2:15 pm

Good informative replies, thanx.
2017 BMW 225xe
2011 Citroën C-Zero

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