Battery Degradation

Mitsubishi i-MiEV Forum

Help Support Mitsubishi i-MiEV Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

vwelham

New member
Joined
Oct 12, 2012
Messages
3
I'm considering the Mitsubishi i for purchase. While researching the EV market , I noticed that battery degradation is becoming discussed on the web concerning the Leaf. Battery bars are dropping off their dashboard and the Leaf range is affected...My question to i-MIEV owners is: What, if any , battery degradation are you experiencing with your i-MIEV? Can you please post your response to let me know if you are , or are not , experiencing problems with the Lithium Ion battery in the i-MIEV.
 
I have the same age and kilometers as Sandange with no issues. However, we are both in moderate climates for owning an EV.

The problem with the Leaf is that it does not contain an Active Thermal Management System. Lithium Ion battery chemistry can not be kept at temperatures above 104F/40C. Our owner's manual gives exact specifications what occurs at that tempurature and how the car will respond to it. The Mitsubishi i does have a ATMS using the onboard climate control system.

There are others here that have owned the car for almost a year and so far we have heard no complaints of decreased range even from those living in much hotter climates. The i MiEV seems to be doing really well out in the world on its own.
 
Over 7500 miles (12000km) since February 2012 and no range change noted at all. Moderate climate with only a few days close to 100degF (38degC). Averaging 4.2miles/kWhr (6.8km/kWh) wall-to-wheels. Love this car!
 
JoeS said:
Over 7500 miles (12000km) since February 2012 and no range change noted at all. Moderate climate with only a few days close to 100degF (38degC). Averaging 4.2miles/kWhr (6.8km/kWh) wall-to-wheels. Love this car!

Same experience as JoeS here, no range change noted at all with over 8,700 miles Since January 2012. Same weather conditions also.
 
As a new i-MiEV owner, I find all this very reassuring, especially in light of Nissan's ongoing problems (I still don't understand why they aren't buying cars back to take the air out of the story). Come next summer, though, I definitely intend to keep my cabin comfortably cooled, which should help keep battery temp down as well. Seems to me sacrificing a little range short term beats all heck out of prematurely aging the battery chemistry.
 
Thank - you to all you owners posting feedback regarding the (lack of) battery degradation so far on the iMiev. Took a test drive this past weekend and I was quite impressed with the vehicle. Please continue to post feedback.
 
Had mine about 5 months and 3,500 miles. I see no loss of range. Time will tell.
 
oakvilleblake said:
Have had ours for 2 months and the range has improved noticeably over time.
I don't think that's the car . . . . or the battery - I suspect it's the result of the driver learning how to drive the car for best ecomomy and range. Too bad there isn't a similar training program for those with ICE powered cars ;)

Don
 
I found this interesting. I wonder if they changed battery packs since then. Anybody know?

http://www.greencarcongress.com/2008/05/the-battery-pac.html
 
spirit said:
I found this interesting. I wonder if they changed battery packs since then. Anybody know?

http://www.greencarcongress.com/2008/05/the-battery-pac.html
There were a flurry of reports in summer, 2011, about Mitsubishi agreeing to use Toshiba SCiB cells in its i-MiEV and other future EV's. But there are also references to the i-MiEV using cells produced by the Mitsubishi-Yuasa joint venture. Maybe Toshiba wasn't able to provide SCiB cells in time, in sufficient quantity, or at an acceptable price. Or maybe they're used in some i-MiEV models but not all. I suppose until i-MiEV owners examine their battery packs closely, we won't really know for sure.
 
alohart said:
There were a flurry of reports in summer, 2011, about Mitsubishi agreeing to use Toshiba SCiB cells in its i-MiEV and other future EV's. But there are also references to the i-MiEV using cells produced by the Mitsubishi-Yuasa joint venture. Maybe Toshiba wasn't able to provide SCiB cells in time, in sufficient quantity, or at an acceptable price. Or maybe they're used in some i-MiEV models but not all. I suppose until i-MiEV owners examine their battery packs closely, we won't really know for sure.
As I understand it, the problem with SCiB is weight, about 50% more than the GS Yuasa for comparable storage. Mitsubishi does use SCiB for a shorter-range model in Japan, where it appears some buyers are more willing to trade range for a more durable battery with greater tolerance for quick-charging. I'm guessing the fact that Japan has a relatively extensive network of CHAdeMO Level 3 chargers makes it easier to live with lower RR numbers, especially if you're comfortable slamming your batteries w/CHAdeMO a couple times in a day (as Toshiba says you should be with SCiB).

In the U.S., we only get the maximum-range battery pack made by GS Yuasa. Given how much grief reviewers heap on the i-MiEV for falling several miles short of the LEAF range-wise, limiting U.S. models to "max-range batteries only" makes sense.
 
15% loss over 3 years, providing you recharge every day, is a lot. I am not sure what constitutes a cycle in this case.
 
The consensus on this thread is that battery degradation is not happening. My question is what will the indicators be of such degradation? Will it be not showing 16 bars after a full charge? Will RR after a full charge drop dramatically after a full charge?
 
I am thinking that would be correct. I am thinking we would see this 15% drop after 45-50,000 miles or earlier. It would depend on the definition of cycle. I would think the BMS would extend the life quite a bit longer. I wonder what the real world test results were.
 
We have bought our i-MiEV with some 4000 kilometers. Range used to be 107 Kilometers. When we bought the car, the battery was completely cycled to recalibrate. Since then range used to be 140 kilometers and even 164 once.

Some 2000 Kilometers later and after the update, range is 100 kilometers. Panic?

I remember we got only 85 kilometers after a full charge but 30 kilometers later it was 91 kilometers.

We used to note every kilometer in a book and count and guess. Today we have become electric oldtimers (3 month :)

We have been on a pirates convention, driven some 204 kilometers with the biggest distance 111 kilometers and the turtle was giving us a fit twice. I am sure she would have carried us the final 9 kilometers but not without complaining.

I stopped filling the batteries to the rim. We are living on the backside of a hill and 1/3 down. So after driving some 10 kilometers the batteries are full and the real voyage can begin. But remember we have to get up the hill again.

It is winter and we have bought a pants warmer for my wife, 12V 50W. The fan is constantly running to keep the windows open and we even use A/C and heater sometimes. Counting and guessing again it is still the same 120 kilometers. It needs a year at least to see if there is a loss and dont forget, driving habits changed too.
 
peterdambier, thank you for your writeup, although I did cringe when you mentioned Turtle. :shock:

Using the Range Remaining readout after fully charging the iMiEV is not a good way of assessing battery capacity. On the RR readout after fully charging we have seen a high of 103miles (166km) to a low of 35 miles(56km), all with relatively new vehicles, simply indicative of how efficiently/inefficiently people drive. I have yet to see the same RR number repeat whenever I fully charge the vehicle.

Quite frankly, if my iMiEV lost 20% capacity I probably wouldn't notice it as simple variations in my driving behavior exceed this number.

I'm hopeful that our CAN investigators will come up with some battery capacity information that may be stored in the vehicle.
 
Since the weather has turned a little colder here in NY, I think my RR number after a full charge has decreased...but I am also driving the car a little harder out of necessity.

I don't think I will know if it is real battery degradation or just the other factors at play, until next spring/summer.
 
Back
Top