Canion Battery Readings

[Zelenec]

Malm, don't you think you should visit your dealer and explain your observations? Maybe there is wrong something else not just expected degradation?

 

[Barbagris]

Seems there is a problem with the way the car calculate SoC. With 88 cells in series, the SoC of the battery is the SoC of the weakest cell. In your first image, Malm, the 73 is at 2,75V: 0% SoC. The battery is out. I think that, in your car, the SoC must show the 73 cell SoC.

And for more comparison, I can show a picture of yesterday, showing less SoC in my car than in your third image (21.5 vs. 25.5), and with higher values ​​of individual (weakest) and accumulative voltages. But may be other conditions (temperature?) affecting the measurement, I don't know.

 

[Malm]

Barbagris, sometimes at 21,5% my battery looks better then yours. Maybe this time my I-MiEV estimated correctly it SoC. Or is giving a lower value then it should. I think it doesn't know how to correctly estimate SoC, unless is standing still without charging for some time, or charged to full.

 

[Malm]

Malm, don't you think you should visit your dealer and explain your observations? Maybe there is wrong something else not just expected degradation?

They will not understand a single word. I just have to take care with voltage by Canion. The energy is there, because I see what it takes to charge, and for 80% it usually takes 14,5 kW.h.

 

[Zelenec]

They will not understand a single word.

Sure they wouldn't, same here :twisted:

I see what it takes to charge, and for 80% it usually takes 14,5 kW.h.

I believe I made a big mistake believing (and claiming) that the capacity of the battery can be determined by measuring electricity used to full recharge. Sorry for that That's not a reliable method.

Even when the battery degrades, recharging consumes the same amount of energy. More the battery is degraded, the greater the internal resistance of the cells, the more energy when recharging is changed to heat and not in the chemical conversion necessary for saving energy input.

I hope I will not have to change my mind again someday :?

 

[Malm]

Zelenec, I think you were right because 2011 Nissan Leaf here in Portugal show 17%/18% degradation (lost one of the 12 bars) and they also take much less kW.h to charge to full.

 

[JoeS]

Oooh, just as another bit of information, on the AEVA found this link from 2010 about Mitsu's BMS:
http://www.analog.com/en/press-release/3_24_10_Mitsubishi_Motors_Adopts_ADIs_Low-Power/press.html

 

[Zelenec]

Zelenec, I think you were right because 2011 Nissan Leaf here in Portugal show 17%/18% degradation (lost one of the 12 bars) and they also take much less kW.h to charge to full.

I guess I'll need to speak to both "teachers" again or even confront them to find the truth about reliable signs of degradation... (confused.jpg)

 

[Zelenec]

Oooh, just as another bit of information, on the AEVA found this link from 2010 about Mitsu's BMS:
http://www.analog.com/en/press-release/3_24_10_Mitsubishi_Motors_Adopts_ADIs_Low-Power/press.html

Is this the correct link, JoeS?

 

[JoeS]

Oooh, just as another bit of information, on the AEVA found this link from 2010 about Mitsu's BMS:
http://www.analog.com/en/press-release/3_24_10_Mitsubishi_Motors_Adopts_ADIs_Low-Power/press.html

Is this the correct link, JoeS?

Zelenec, you're right as now that I looked at it closer I see little useful information in what is basically a press release. They do provide links to their hardware, but then wading through all their associated ap notes and technical articles is waaay too time consuming - I'll pass. :?

 

[Malm]

Transform 97,5% of SoC in 100% in an eye blink. The best of the malmonastic magic in video.

http://www.youtube.com/watch?v=dUFVipJ8vGM

 

[RobertC]

Transform 97,5% of SoC in 100% in an eye blink. The best of the malmonastic magic in video.

http://www.youtube.com/watch?v=dUFVipJ8vGM

What was voltage on each of the 88 cells as shown on Canion Battery Status? It looks like some of them were not at the peak of 4.105 volts.
Also, I enjoyed the Queen's 'A Kind of Magic' as the background music. I really miss Freddie Mercury.

 

[Malm]

When it is ending the charge, all cells are at 4,105V, total is 361V. When it ends charge some cells turn a little less weaker - 4,1V, 4,095V.

I think when I tried to make the charge when it was full, it just refused to take any charge at all.

 

[DonDakin]

Hello all,

Here is some temp data from my neck of the woods.

I keep my iMiev in the garage that is heated lightly. The garage temp is about 4 deg C when the temp outside is -10 Deg C and about 0

Deg C when the temp outside is -15 Deg Cand below. The car is left in the parking at wotk from about 8 Am to 5PM then driven home.


This is the temp data for my area for Jan 23 and 24th.

max mean min
Jan 23 2014 -17.5 °C -20.4 °C -23.2 °C
Jan 24 2014 -9.7 °C -16.8 °C -23.8 °C



Here is my Battery temps after charging up in the garage on Jan 24th in the morning before going out to work.

Here is the Battery temps after the car sitting from 8:00 to 5:00 outside with the temp going from -20 Deg C to about -10 Deg C.

This is my drive home energy usage for Jan 23rd on the 11 Km trip back home from work. Heat blasting and very comfortable in the car.

So ON THE 24TH the battery started out at an ave temp of 7.3 deg C stayed outside at -20 deg C approx for about 10 Hours and ended up

at -6.2 deg C loosing about 1.35 Deg C per hour average.


It's interesting to see that the temp curves have a consistent shape for low temps as well as the hogh temps that we see from malm on

hot days. In his case the innermost batterys overheat and loose capacity faster due to the overheating condition. In my case the inner

batteries stay warm and do better then the outtermost batterys which chill to ambient faster. The only problem I wonder about is this

notion that charging lithiums below zero is bad for them. I don't know if this is valid for the imiev. If it is then it could be that

in cold climates the outermost batteries will suffer more in the long term being charged at lower temps more often compared to the

innermost ones.

In any case it seems to me that some form of air recirculation should be done in the battery in order to exchange heat from the warm

cells to the colder ones. I don't know if this would work but I guess that the more even the the temp is over then entire pack the

better for all the cells in there.

Don.....

 

[Malm]

I think we should be able to change the cells position, one or twice an year. The car only charge to 95%?

 

[DonDakin]

Hi malm,

The car charges to 100 % I just don't charge that high very much but since it was very cold I let it charge as much as possible until I left for work which was 95% in this case.

It would be nice to be able to rotate the cells but probably not a practical thing to do. The only thing I can think of is to have air recirculating in the battery pack.

Have to think about it a little more it would be nice to design a system that would perhaps return air to the cabin and cycle it thru the battery. I'm not sure if there're is anything bad for the passengers like some kind of chemicals from the battery that should not be circulated in the passenger compartment.

It would be nice to have a system that would take care of a few things:

Evenly cool and heat the battery
Transfer heat from battery to the cabin if required.

Maybe one day when I have time on my hand I will open the pack and see if installing fans in there can be done just to move the air around. Maybe just hot wiring the blower in there to be able to turn it on at will would generate enough air movement to unify the cell temps more.

Don......

 

[Malm]

The car should be made to be easy to change the cells from time to time. It was obvious, since the beginning, that the inner cells would heat more.

 

[PV1]

DonDakin, if your car has either the cold weather package or quick charge package (at least US models), the easiest way to circulate air in the battery pack is to remove the servo that controls the airflow into the pack. it's located on the inner side of the footwell, right by the floor vent. This will allow air, either heated or cooled if needed, to enter the battery pack and circulate. The airflow is then controlled by the HVAC controls. I did this when the first cold snap (-10 F) hit and I was driving 60 miles a day that week. I was able to park in a fully heated garage and charge for about an hour 10 miles into my trip. I left the key on while charging and directed the warm air of the garage into the freezing battery pack. It didn't really make a difference except for more powerful regen. This mod would have more benefit in cooling the pack (or a few hot cells) than warming it up.

 

[DonDakin]

Hey PV1

That's a good idea. I have not yet played with the inlet to direct air to the battery. In my case I could drive home and leave the car in the garage directing heat into the battery pack for alittle while before charging to get the temp up above zero.

I will have a look at that.

Thanks for the tip

Don.....

 

[Malm]

http://www.youtube.com/watch?v=RkB2TG-gsvU

Slow charge as seen by CaniOn