How many years / miles can we expect battery failure?

[genec]

I couldn't find the answers in this forum.
I have a 2012 with 29k miles.
I'd like to have at least a ballpark of how much time / miles I have left until battery failure.

 

[jray3]

You shouldn't experience battery failure, but if a cell does fail, you'll notice a rapid decrease in the number of bars visible after a full recharge.

Malm is the first list member to see a permanent loss of capacity in his battery due to age and use. Read up on his posts.

Normal aging for our batteries will be a gradual loss of capacity that would extend out for many years if we decide that a 15 year-old car with 20 miles of range still meets our needs.
In simplified terms, the battery came with greater than advertised capacity, hidden below the last bar on the State of Charge gauge. For the first few years of use, that hidden capacity 'in the turtle' will be unused by most folks. Only after the car loses all of that buffer will the turtle truly mean "pull over now!" Last summer, I traveled a careful 8.5 miles on the turtle one time, though I've never driven the car all the way until it shuts down.

I expect to hit 80,000 miles before the battery is below 80% capacity, and still show 12 bars after recharge at 100,000 miles if I'm lucky. Unless an attractive battery replacement/upgrade option emerges, we'll likely run the car all the way down past 50% capacity loss, or under 30 miles of useful range before spending significantly on an upgrade or replacement.

This is a reminder to fire up Canion and check my fully charged stats...

 

[PV1]

Nobody really knows how long these cells will last. What we do know is there is an 8 year/100,000 mile warranty on the battery pack. Some fail at 5K miles, some at 22K (mine, for instance), and some may never fail. What I do think is that earlier cells (pre-Boeing 787 incident) are more prone to failure than newer cells, as some manufacturing improvements have taken place since then. That, and Mitsubishi/GS Yuasa has more real-world data and may have made some improvements on newer models and newer battery packs.

Over the 3 years I've been on this forum, I have heard accounts of five battery failures, as well as one of my own. Per my own estimations and math, the cell failure rate is still well below 1%, as only one failing cell will dramatically affect the range of the i-MiEV.

One of the oldest, if not the oldest, i-MiEV on this forum is a 2011, and has yet to experience a failure of the battery pack. Has its capacity degraded? Yes, but all cells are still pretty healthy and the car has no reported issues charging. It just has a bit less range than it did before.

If there were a certain known failure point, you could almost guarantee it would be longer than the warranty period. Having to replace nearly every battery pack at 98,000 miles (hypothetically) under warranty could spell a lot of financial trouble for Mitsubishi. Given that a LEAF owner has driven more than 100,000 miles with little issue, I think that further bolsters the longevity of lithium ion if not pushed all the way to the charge limits. Cell phones and laptops use the full voltage range of lithium, while EVs like the i-MiEV only use about 80% for their usable range. Between that and the operating temperature (phones are almost always 90 F and up), batteries in EVs should have no problem lasting 10 years. Really, the end of the usable life is whenever the range no longer meets your needs. I drove my white i-MiEV for two weeks with a failing cell, and it was only the last two days did things get interesting (10 mile range).

 

[Malm]

Two answers to the question, both with references to my experience (I think the 2011 I-MIEV is mine).

My car has 80.000 km and 4 years and 2 months. Has no evidence of any problem at this moment. It goes to an annual check every year, with any problem reported.

One thing that I know is that, now, every bar is less energy then when it was new, but I can do 80 km with one charge at normal speed (70/80 km/h).

I think that there are others I-MiEVs with the same age that will behave like mine, specially those that are in hot climates, like Australia, but users simply can't yet see the difference.

The highest battery degradation rate of mine, I think, is because I used it for long trips in summer, and my battery has been for several days at 40-50ºC, for sure. In the last year I became aware of the problem and I use the car in a way that I reduce the heat in the battery significantly. So, now I believe degradation rate of my battery is significantly reduced compared to first 3 years.

So, for the moment, everything is like new (charges 16 bars, all cells go to 4,105 or 4,11V, turtle with energy to drive 5-10 km), excepts that one complete charge is less energy (between 10 to 30%, I really can't tell how much is the loss).

I think it is a question of luck, maybe at the end of 10 years some of us will have a battery with 70% capacity with any problem, and other, after the end of the 8 years warranty, experience battery failure.

 

[mentaluproar]

What would I look for in the cannon app that would tell me if a cell was bad or if the battery has a low state of health? I know leafspy can do it.

 

[Malm]

If a cell is going to fail soon, it will charge significantly less then the others at full charge. And the difference will became bigger and bigger day by day. I also know Leafspy, and Canion only can show you the voltage of the 88 cells. Our experience and knowledge (that grows here with the information that we share) will tell use when there is a problem.

 

[kiev]

What would I look for in the cannon app that would tell me if a cell was bad or if the battery has a low state of health? I know leafspy can do it.

Notice the one cell that is lower than all the rest (previously posted by PV1)

 

[PV1]

Yep, CaniOn will show one or more cells at a lower voltage than the others (more than .01 volt difference). As the condition worsens, the charge gauge on the dashboard will show full charge at a reduced number of bars. For example. When first starting my car after a failure developed, my gauge showed a full charge as 13 bars and not the usual 16 bars. After each charge, there were less bars each time. Eventually only charging to 3 bars the morning I drove to the dealer.

The screenshot posted by KiEV was my car at the dealer when dropping it off. The first screenshot when I saw the condition showed cell #10 .08 volts below the rest. While that may not sound like much, each cell only drops roughly .6 volts over the charge range from 1 to 16 bars.

Other than a cell being unusually low in voltage, the SoC will also not be 99-100% after a completed charge cycle.

 

[rosacastillon]

At the risk of making my $32K original priced 2012 i-MiEV worth even less than it's current $8-9K resale value---

My wife drives her 2012 i-MiEV 25-26 miles round trip per day commuting to work. We charge after two round trips, after 50-65+ miles.
We never charge the battery when it is more than 50% charged. We often drive it to 1 or 2 bars remaining, occaisionally reaching turtle mode (once everly 3-4 months).

We live in Las Vegas. Daytime temperatures in the summer reach 106 frequently. Ambient temperatures reflecting off asphalt are higher, approximately 109+. Charging is done in the summer in a 90 degree covered garage, allowing for cool down time, if possible.

Our first battery lasted two Las Vegas summers (2013 and 2014) and 11K miles. It's range degraded from (originally) 62 miles down to 38-42 miles on a charge (66% remaining, for a 33% decrease after 2 years). I documented the loss of range, daytime temperature, temperature at charging, % loss of capacity, both by miles and by bars, allowing for losses due to A/C by resetting the trip odometer, carefully every day, for 3 months. I pointed out my vehicle was warranteed to deliver more than 80% of it's original range after 5 years, and 70% after 10. I sent my data sheet to the dealer when I took it in for testing. I wrote letters to the Head of Mitsubishi North America, also including my data. I also explained I thought that I was doing the Beta testing for i-MiEVs in my climate.

The vehicle has indicated overly optimistic mileage that has resulted in my wife being stranded once, at midnight.

Mitsubishi replaced the battery at no cost, but ordering from Japan took two months. We are now on our first summer on the 2nd battery, and range so far is excellent (70+ miles). The vehicle meets our needs, except for the limited range. We will see if the second battery can withstand the Las Vegas heat sometime next summer (2016).

There were two i-MiEVs sold in Las Vegas in 2012. I think none in 2013-2015. The vehicle is excellent. The battery might be for temporate climates only.

-Mike Horsley for Rosa Castillon

 

[Phximiev]

I have the same questions since we live in Phoenix. This summer has seen some very hot days, up to 114 over severals days, yesterday 112 or so. At the moment, we haven't seen any degradation, but we do wonder. Mitsubishi replaced our battery last December.

I also wonder, but can't find anything to support the notion, if Mitsubishi didn't make their battery more heat resistant over the last couple of years, given the Nissan lawsuit and their experienes. The LEV 50 appears to be 2009-2010(?) technology and it would seem that they could/would have done something to the chemistry since, but perhaps not announced it.

All very speculative.

 

[pbui19]

For vehicles in hot climate, I wonder if the flapper mod to divert cool AC air into the pack would mitigate the temperature degradation ? discussed in the "Passive Cooling" thread:

http://myimiev.com/forum/viewtopic.php?p=23161#p23161

of course the range would be reduced, but it's worth saving the pack, especially after warranty period.

It would be great to see Canion display of the battery temperatures.

 

[PV1]

The closer we keep the cells to 75 degrees F, the less temperature stress and degradation we'll see.

It seems that hot temperatures gradually degrade the pack and cold temperatures below freezing can cause cell failure. Of course, there have been a couple of cases (including mine) where the cells get hot and then suffer a failure. But, we still don't know if it is a cell failure, whether or not caused by internal debris (Dreamliner?), or if it is a component failure on the management board. With my cell failure and others, we noticed a slow trend of decreasing voltage, which suggests a component short on the management board. I would think an internal cell short would be more dramatic. The cell still charges, discharges, and otherwise behaves like the other cells, it's just that the voltage continually drops over the span of a couple of weeks, eventually to the point where the car is unusable (I had a useable range of 9 miles by the time I dropped it off at the dealer).

 

[JoeS]

...My wife drives her 2012 i-MiEV 25-26 miles round trip per day commuting to work. We charge after two round trips, after 50-65+ miles. We never charge the battery when it is more than 50% charged. We often drive it to 1 or 2 bars remaining, occaisionally reaching turtle mode (once everly 3-4 months)....

Boy, and I thought I was conservative (at the top end)! You're doing great at keeping the lower voltage in high temperatures at the upper end, but I don't understand driving the SoC down so low. I would worry that, with a peak current of over 150A, that now becomes a significant multiple of the near-depleted battery's capacity.

In over 50,000 miles of driving now three i-MiEVs, I've never seen turtle. It's actually quite easy to stay away from there.

In your shoes I would charge for maybe 1-1/2 hours every morning after the battery has cooled off overnight, and keep it between, say, 4-5 bars and 9-10 bars. 25 mile daily drives in the i-MiEV is a dream commute, and you can have your aircon blasting away the whole time.

Back on-topic, everyone has pretty well answered the OP. IMO, after 3-1/2 years that the i-MiEV has been on the market in the US, it's still too early in the game to even worry about battery failure. The i-MiEV I bought new now has almost 40,000 miles on it (carefully nurtured battery), and its range is indistinguishable from my two used i-MiEVs: one with a brand new pack earlier this year and the other with around 18,000 miles on it.

 

[DriveGreen]

I took our car to the Mitsubishi dealer to review the outstanding recalls and take care of them.

While there, I was shown on the screen of the 'service advisor' that Mitsubishi has increased the main (drive) battery warranty from 8years 160,000 km to 10 years 160,000km on all 2012 cars, like ours. I think it is good news. (We have just rolled over 10,000k.) What I see the major issue could be, other than hot climate, is the way the battery is charged. The drive till down to 20% and charge to 80% idea is good on paper, but totally unpractical with a small drive battery we all have.

 

[ChaplainBill]

I have a 2012 and have noticed a big drop in range lately= I started with 80-90 miles after every night of charging, and now it is only 55 consistently. I took it to the local Hawaii Dealer, and left it for two weeks for them to study the problem, and get advice from others who have dealt with this kind of failure. My dealer did nothing, saying the drop was "normal" and that the batteries were still within the range I should expect. I think, based on what I have learned here about replacing batteries in similar situations, that I need to become more of a "squeaky wheel" if I want to get some help?! Who should I contact at Mitsubishi of North America to get them to advise my Hawaii dealership to take this problem seriously? Aloha, Chaplain Bill Crockett.

 

[PV1]

A sudden drop like that isn't what I'd call normal. If you have an android phone or tablet, I'd invest in an OBDLink MX so you can get a reading of the cell voltages. Usually a dramatic drop in RR is the first sign of a cell failure, followed by the inability to charge to 16 bars.

 

[Malm]

A sudden drop like that isn't what I'd call normal. If you have an android phone or tablet, I'd invest in an OBDLink MX so you can get a reading of the cell voltages. Usually a dramatic drop in RR is the first sign of a cell failure, followed by the inability to charge to 16 bars.

I don't agree. For me its normal to see an I-MiEV lose 20% from a day to the other, without any problem. I explained that before, after some time, can be years, the car will, by itself, recalculate its capacity. And if the car find that the capacity is 20% lower then when it was new, it will recalculate it and then will give a number of range remaining in line with that new recalculated capacity. If it has a problem, then you will not see the 16 bars. That is not the case.

 

[Malm]

At the risk of making my $32K original priced 2012 i-MiEV worth even less than it's current $8-9K resale value---

My wife drives her 2012 i-MiEV 25-26 miles round trip per day commuting to work. We charge after two round trips, after 50-65+ miles.
We never charge the battery when it is more than 50% charged. We often drive it to 1 or 2 bars remaining, occaisionally reaching turtle mode (once everly 3-4 months).

We live in Las Vegas. Daytime temperatures in the summer reach 106 frequently. Ambient temperatures reflecting off asphalt are higher, approximately 109+. Charging is done in the summer in a 90 degree covered garage, allowing for cool down time, if possible.

Our first battery lasted two Las Vegas summers (2013 and 2014) and 11K miles. It's range degraded from (originally) 62 miles down to 38-42 miles on a charge (66% remaining, for a 33% decrease after 2 years). I documented the loss of range, daytime temperature, temperature at charging, % loss of capacity, both by miles and by bars, allowing for losses due to A/C by resetting the trip odometer, carefully every day, for 3 months. I pointed out my vehicle was warranteed to deliver more than 80% of it's original range after 5 years, and 70% after 10. I sent my data sheet to the dealer when I took it in for testing. I wrote letters to the Head of Mitsubishi North America, also including my data. I also explained I thought that I was doing the Beta testing for i-MiEVs in my climate.

The vehicle has indicated overly optimistic mileage that has resulted in my wife being stranded once, at midnight.

Mitsubishi replaced the battery at no cost, but ordering from Japan took two months. We are now on our first summer on the 2nd battery, and range so far is excellent (70+ miles). The vehicle meets our needs, except for the limited range. We will see if the second battery can withstand the Las Vegas heat sometime next summer (2016).

There were two i-MiEVs sold in Las Vegas in 2012. I think none in 2013-2015. The vehicle is excellent. The battery might be for temporate climates only.

-Mike Horsley for Rosa Castillon

Ok. Many, many, many thanks for your information. In 2 years, a 33% decrease. Without loosing any bar. For me, definitively the effect of high temperatures. Much higher then mine, that has a degradation bellow 30% in 4 years (35 Ah versus a new 46,5 Ah). In the first summer you will not see differences because what happens is that the range will not go down until the weakest cell is touching 2,75 V.

Most interesting - "The vehicle has indicated overly optimistic mileage that has resulted in my wife being stranded once, at midnight." It happened to me. Stopping without going to turtle, and showing something like 4 miles range remaining. The battery was losing capacity fast but the car was not recalculating the capacity. Because, as I said many times before, the car only recalculates its remaining capacity after some time.

"The battery might be for temporate climates only"--- I can't agree more. I believe in that since 2013. So, you all know how, from a day to another, my car is now getting temperatures from a much higher latitude.

One of the most valuable information in this forum. Again, many thanks.

 

[JoeS]

I have a 2012 and have noticed a big drop in range lately= I started with 80-90 miles after every night of charging, and now it is only 55 consistently...

Chaplain Bill, I wouldn't be too concerned about this unless, when fully fully charging the car, it fails to achieve 16 bars. As long as the car gets you where you're going and you're not often trying for >60miles on one charge, I'd simply live with it and see what develops as you still have many many years of warranty left (and you're already on record with Mitsubishi as having brought the car in).

With my brand-new battery, my fully-charged Range Remaining varies between 50 miles and 90 miles, and is simply an indication of my erratic driving. On the other hand, my wife usually gets RR>70 miles (unless she hopped onto the freeway) on her i-MiEV with almost 40,000miles on it whenever we (rarely) fully charge it. It doesn't take much to significantly lower this number (e.g., a leadfoot takeoff from a traffic light). I defy anyone to predict what their RR will end up being (+/-1 mile) after plugging in the car and fully charging, and it becomes quite a game in the family to try to outdo each other. :evil: :lol:

 

[Phximiev]

Found this from Mitsubishi, is it a new upgraded LEV 50 or the same with a different name?

And perhaps one could buy just one?

http://www.gsyuasa-lp.com/LIM50E-lithium-battery