matija wrote:Greetings everyone,
I have recently noticed that cani0n is now showing the Ah value of our battery modules. This raises few questions.
What is the new value of our Yuasa LEV50 cells ? They are branded as 50Ah. I doubt cani0n would really show 50 in brand new car. But if it would that means I have lost nearly 30% as cani0n shows 35.25Ah for me.
Nominal rated cell capacity is 50Ah, but the BMS on the car does not charge the cells to 100% (4.2 volts per cell) but only to 4.1 volts per cell. Depending on what reference you take as gospel, 4.1 volts on a cell chemistry that is 100% charged at 4.2 volts is about 90% charged.
If this is the case, the usable cell capacity brand new will only be about 45Ah, and certainly not 50Ah when the cells are only charged to 4.1v. Evbatmon apparently uses a figure of 46Ah, so for lack of a better figure I have been basing my degradation measurements on 100% SoH = 46Ah.
I've been graphing my Ah (and assumed SoH based on 46Ah=100% SoH) since I've had my 2011 Ion and unlike some other reports in this thread, I've never seen a "rebound" in the figure - it has been a steady linear decline with mileage/age. It's hard to tell if it is related to mileage or calendar age because I do a constant mileage every month, so the only clue would be whether degradation varies between summer and winter. (Due to heater use vs no heater use)
Here are my results so far:Full image.
I have a Lexia 3 PSA dealer diagnostic tool that works with the Ion and C-Zero (but not i-Miev) and I have been gathering the Ah figure from that - even the official diagnostic tool provides no guidance on what Ah capacity a new car should have.
I've seen mention in another thread that "older" versions of this car have a "manual BMS re-calibration procedure" that can be performed by the diagnostic tool to get it to properly re-test the capacity of the cells - I have seen what looks like this calibration procedure in the main BMS ECU and how to initiate it in the PSA Diagbox software but I have not yet had the guts to run it. Mainly because it looks like it will take something like 8-12 hours to run the test, and I need to use the car every day...
It tells you to leave the car plugged in to both power and the laptop during the test, so I'm assuming it will use the heater to discharge the battery fully (which would take about 3 hours) and then automatically charge it back up again. (which would take about 4 hours)
Next time I have a long weekend and don't think I'll be needing to use the car for a couple of days I might just try it to see if the Ah figure changes!