measuring capacity loss through CanIon

[matija]

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.

Although 50Ah * 88 cells * 3.7 nominal voltage does return 16kWh value.

Does anyone know how to re-initiate reading of Ah in cani0n ? This measurement was done when battery was cold and not full (14°C, 82% SoC)

I've read a lot of how voltage works in those cells, how newer cars can get 0% soc at quite high voltage (like Malm getting it at 3.6V), while older packs could go near the 2.75V limit. How SoC loss is compensated with shrinking the "turtle range", etc.

So, perhaps new car would return 50Ah to cani0n. If that is true, perhaps with BMS allowing to discharge cells deeper and deeper as they age, actually represent almost no visible SoC loss to users ?

I would love to hear others opinion.

 

[Aerowhatt]

It’s cool that the update is showing this info since EVbatmon is such a PIA.

That’s correct that Mitsu hid part of the battery capacity from us to basically eliminate any user sense of battery degradation. Brilliant really, since degradation is kind of steep at first and then slows. Basically if you use the car as intended (never seeing turtle or running down to the bone). You would never know from the dash that the capacity was slowly decreasing. In doing so they also make the battery last longer by designating the “bottom” above the actual bottom.

I don’t recall anyone with reading above 47 ah for these battery cells. Manufacturer specs are a slow discharge under ideal conditions. Certainly not what happens in an EV!

It looks to me like it is the “calibration charge” which returns this info to the system. The three dates shown on my canion read out, all coincide with trips to the mountains followed by an uninterrupted charge to 100%.

The history panes in canion can be a bit misleading since they are disconnected in time from the current summary list on the left of the screen.

Aerowhatt

 

[matija]

Interesting read. I’m wondering though, what’s tte Ah value read by cani0n on new i-miev. Or, from which value downwards would one start noticing range drop?

I know that I do not notice quarter drop in range, although numbers suggest it - 35.5Ah / 47Ah = ~75% SoH.

 

[Aerowhatt]

Does anyone know how to re-initiate reading of Ah in cani0n ?

So this is interesting. I had set my iMiev to charge in the early morning hours of Saturday on Friday evening. Apparently I got some food poisoning and spent most of Saturday down for the count . As a result the car charged as scheduled and was left plugged in until late Saturday night. During that period it returned two new AH and temperature readings for the pack on the Ah screen of canion. So triggering a new reading is not only as I had guessed. Since it also recorded one when fully charged and left plugged in all day. I have caught both of our cars re-connecting with the EVSE for a few minutes, hours after completing their witching hour charge cycles, While I was fiddling about in the garage in the morning before unplugging them. I'm assuming that is what happened yesterday some time since the first reading was a bit lower reading than the second one was.

Aerowhatt

 

[matija]

Will definately try this, with external power source for mobile device that runs cani0n. Although, I believe reading at low temperature numbers are not in favor of getting high Ah readings. Just had my battery at 2°C this morning.

Somehow I got new reading though, it was 35.25Ah at even lower temperature. I'm wondering what numbers will pop up in the spring. And I'm still thinking what do compare those readings to. 42Ah, 47Ah, or is it perhaps dynamic, just with lower reserved margin of the battery.

 

[rnlcarlov]

EvBatMon has shown Ah for a while now. It considers 48Ah as 0% degradation.

 

[Aerowhatt]

EvBatMon has shown Ah for a while now. It considers 48Ah as 0% degradation.

I wish there were more info available from Mitsu on this subject. I don't have any faith in EvBatMon or the accuracy, origin, or viability any parameters it sets.

Aerowhatt

 

[Aerowhatt]

So I had another deep discharge and full recharge but no new Ah value was added to the vehicle log. Perhaps it is just periodic in nature when the system records a value??

Aerowhatt

 

[rnlcarlov]

So I had another deep discharge and full recharge but no new Ah value was added to the vehicle log. Perhaps it is just periodic in nature when the system records a value??

Yes, I believe it is periodic. Triplet owners here in Portugal have observed that it desceases 0.1Ah about every 20-something days. Then once a year it does a recalculation based on some sort of internal test, which can push the Ah higher or lower, depending on the actual battery condition.

 

[matija]

Someone I know got another reading during long trip around 350km from previousone. I however, got it just randomly during short 15km commute, around 500km from previous one.

I wonder, if Ah reading at 5°C is to be treated identically as the one gotten at 25°C ? We know that battery capacity differs with temperature.

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.

 

[Aerowhatt]

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?

Aerowhatt

 

[rnlcarlov]

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.

 

[matija]

Good informative replies, thanx.

 

[Barbagris]

Does anyone know why I do not have any reading in the Ah field?

CanION is updated, the car is a clone (Peugeot) and the OBD-II is an STN1170.

Everything measures perfectly, just does not give me any value for "Ah" :x

Any ideas?

 

[priusfan]

Bonjour Barbe Grise
What is your interface?
What is the firmware level?

I know previous firmware could not allow to access this info.
Maybe you can try to update the firmware .
see here: https://www.scantool.net/downloads/updates/stn1170/

Xavier

 

[Barbagris]

Bonsoir, Xavier, merci de votre attention!

My interface is a STN1170, but no from scantool; mine is from AH Design
http://ahdesign.us/blog/stn1170-bluetooth-obdii-adapter/

Until now, everything had gone perfectly, but I do not read the capacity value

I think it's not a good idea to update the AH Design device with the scantool firmware (if it is possible)

Well, now I know what the problem was, maybe it's time to buy a new interface.

Merci beaucoup!

 

[JoeS]

Barbagris, my fairly old STN1170 from AH Design works just fine using CaniOn v141 and gives me Ah reading.

 

[Aerowhatt]

Bonsoir, Xavier, merci de votre attention!

My interface is a STN1170, but no from scantool; mine is from AH Design
http://ahdesign.us/blog/stn1170-bluetooth-obdii-adapter/

Until now, everything had gone perfectly, but I do not read the capacity value

I think it's not a good idea to update the AH Design device with the scantool firmware (if it is possible)

Well, now I know what the problem was, maybe it's time to buy a new interface.

Merci beaucoup!

Perhaps just give it some time. I know that when I plugged my wife's "i" into the canion app it did not register AH for hours if not a day or more. If memory serves canion was monitoring a charge cycle when it popped up. Looks to me like it's canion that stores the history etc. So from what I saw the first reading took a while to show up.

Aerowhatt

 

[priusfan]

@BarbeGrise :mrgreen:
It should be possible to update the stn1170 from Andy.
It is necessary to use a laptop (with BT!!) and use the StnFirmwareUpdater.exe included in the download.

If you decide to buy another interface, the choice is between obdlink lx and OBDLINK LX :mrgreen:
much better to buy directly in US....

Xavier

 

[Barbagris]

@BarbeGrise :mrgreen:
It should be possible to update the stn1170 from Andy.
It is necessary to use a laptop (with BT!!) and use the StnFirmwareUpdater.exe included in the download.

Maybe it has not been a good idea.

Software downloaded, laptop (Windows 10) connected by Bluetooth (COM3), launched the program.

Connecting to device
Connection successfull

,,,and program crashed. Image.

Try several times, reseting the laptop, try compatibility Windows 8, 7, XP. Always start, and crash.

And the BT interface seems to have been damaged; canion says "connected", send some few commands, and, again says "connected", in a eternal loop.

If you decide to buy another interface, the choice is between obdlink lx and OBDLINK LX :mrgreen:
much better to buy directly in US....

OK.
At eBay I see several "OBDLINK LX", half the price... but from China. :roll:
At Amazon (Spain) it is supplied by a French seller (no customs) but this seller is "new" (the dongle is from China? USA?) :roll:
I will buy it at Amazon USA. In a few weeks we will comment (I hope)