Miles vs age on battery degrading question

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evboy

Well-known member
Joined
Jan 12, 2015
Messages
198
I'm looking at a 2014 spark ev. u can buy them on carmax for 10500. My question is i only drive about 3500 miles a year. i was concerned, if i buy a 2014 spark with a123 batteries in them, they wont have a replacement, since its not a LG battery like 2015. Should i quit worrying since 10 years of driving is only adding 35000 miles to it? will my battery still hold a good range with only 35k added or will it lose alot of range anyway after 10 years because the battery aged 10 years. If I by a used one with 15k miles on it, it will only have 50k on it in 2027. What do u guys think. Should i buy a 2015 instead which cost more but has a LG battery in it. Will the battery degrade with age even if I dont put alot of miles on it? Will a 2014 spark ev with 50k miles on it today have the same range as a 2014 spark ev with 50k miles on it in 2027 ?

Also, the Nissan leaf has completely collapsed in resale value. U can buy a 2013 for 6500. do u see the spark dropping like that or is it exclusive to the leaf since they didnt use liquid cooling on their battery.
 
You raise some interesting questions.
AFAIK, there is 'shelf life' and 'usage life' with Li-ion batteries.
Degradation is just a fact of life with batteries of any chemistry.

I started to record it on my phone. I have dozens of pics of the displays at shutdown when more that 50% has been used.
I have the spread sheet ready with 1 row of data. Some snowy boring day I'll enter all the data I have. I started late. I don't have any from when it was a newer car.
I'm still not finding an exact answer for kWh rating of the '14 pack, but it appears to be bigger than the '15, correct?

Why worry about an event 8 yrs out? You'd be a very gentle user.
Some data shows shelf life is longer if not stored at 100% SOC. If you are not dealing with extremes in temp, you could leave it unplugged and not constantly at 100%.

I wonder if: externally the packs are identical and the power and data connections and the coolant connections are the same on both years.
Hopefully none of us will be reporting on this issue for a long, long time. :mrgreen:
 
You can also avoid filling to 100% by using 'departure time' charging mode, and setting the departure time to be later than you actually leave. For example, if you always leave the house at 8:30 AM, set 'departure' at 9:30 and if you leave at 8:30 your battery will be at about 85% SoC. If you remember to unplug on the weekends around 8:30-9:00, you'll never fully charge the battery.
 
evboy said:
I'm looking at a 2014 spark ev. u can buy them on carmax for 10500. My question is i only drive about 3500 miles a year. i was concerned, if i buy a 2014 spark with a123 batteries in them, they wont have a replacement, since its not a LG battery like 2015. Should i quit worrying since 10 years of driving is only adding 35000 miles to it? will my battery still hold a good range with only 35k added or will it lose alot of range anyway after 10 years because the battery aged 10 years. If I by a used one with 15k miles on it, it will only have 50k on it in 2027. What do u guys think. Should i buy a 2015 instead which cost more but has a LG battery in it. Will the battery degrade with age even if I dont put alot of miles on it? Will a 2014 spark ev with 50k miles on it today have the same range as a 2014 spark ev with 50k miles on it in 2027 ?

Also, the Nissan leaf has completely collapsed in resale value. U can buy a 2013 for 6500. do u see the spark dropping like that or is it exclusive to the leaf since they didnt use liquid cooling on their battery.

This is the capacity of my 2014 Spark EV over 3 years.

The graph was created from readings off the energy screen after discharges of greater than 50%.

I was disappointed at the level of degradation.

kevin
SparkBattery.png
 
Maybe 2014 degrade quicker than 2015? I measured my 2015 few months ago by charging to full and taking a reading at every 1% or 0.1kWh used and plotted to find capacity at 100%. I got 18.1 kWh at 13K miles. More recently I again charged full and took 4 data points (about 20%, 50%, 60% 80%), and it came out to be 18.3 kWh (yes, higher, but probably not as accurate). It seems degradation after 1.5 years and hundreds of DCFC doesn't affect battery capacity much.

But then, my usage pattern is very different from yours, though I think I'm more abusive in that I drive 2000 ft uphill high speed on almost every drive session.
 
kevin said:
evboy said:
I'm looking at a 2014 spark ev. u can buy them on carmax for 10500. My question is i only drive about 3500 miles a year. i was concerned, if i buy a 2014 spark with a123 batteries in them, they wont have a replacement, since its not a LG battery like 2015. Should i quit worrying since 10 years of driving is only adding 35000 miles to it? will my battery still hold a good range with only 35k added or will it lose alot of range anyway after 10 years because the battery aged 10 years. If I by a used one with 15k miles on it, it will only have 50k on it in 2027. What do u guys think. Should i buy a 2015 instead which cost more but has a LG battery in it. Will the battery degrade with age even if I dont put alot of miles on it? Will a 2014 spark ev with 50k miles on it today have the same range as a 2014 spark ev with 50k miles on it in 2027 ?

Also, the Nissan leaf has completely collapsed in resale value. U can buy a 2013 for 6500. do u see the spark dropping like that or is it exclusive to the leaf since they didnt use liquid cooling on their battery.

This is the capacity of my 2014 Spark EV over 3 years.

The graph was created from readings off the energy screen after discharges of greater than 50%.

I was disappointed at the level of degradation.

kevin
SparkBattery.png
I have been collecting Energy Info for my 2014 Spark EV 2LT since March 2016. The results for 57 charging sessions fall almost exactly on Kevin's graph for the interval of 4500 miles to 8000 miles. My data shows a battery capacity drop of .3 kwh for the 3500 mile interval. My 2015 Spark EV 2LT actually shows a .3 kwh increase in battery capacity for 70 charging sessions between the interval 8500 to 14000 miles.
 
sounds like the lg battery is better. i assumed that since they are a huge company and a123 was a startup. lg is a technology god and makes tvs cell phones batteries.... u name it. i guess i should stick to 2015. maybe i wait for june for a little more depreciation. i hate buying a car that isnt at least 3 years old.

also do u see it collapsing in price like the Leaf. They are giving 2013 leafs away. buying a new leaf will go down as the worst purchase you could ever make.
 
evboy said:
sounds like the lg battery is better.....
How do you know without seeing similar plots from a bunch of '15 Spark EV's?

As they/we say in the EV biz,,,,, Only time will tell.
 
hi. I haven't graphed mine (I have a 2015), but I drive mine as a commuter and have had it for 19 months. in that time, I've driven it 17k miles, and my commute is very similar every week. I've noticed zero degradation in the range of my car so far (all things being equal). by that, I mean that for similar weather/temp circumstances, I get the same range out of the car. I'm extremely pleased about this, and forsee no battery issues in the future for me. btw I have always charged on my L2 at home never DCFC, and I try to not go below 20% battery (but I have a handful of times).
 
Norton is correct in that you need to have lot more data to draw conclusions about 2014 vs 2015 in general. However, given that I drive down to "low" (1 mile remaining) few times and often down below 10 miles remaining as well as hundreds of DCFC (several times a week) and only got 0.3 kWh change from 18.4 kWh that it's supposed to be from factory, it seems my 2015 battery does quite well even with my usage pattern. My GOM still shows around 100 miles few times that I did charge to 100%. While I don't know how abusive Kevin is to his 2014, it'd be hard to top the level of use my 2015 has experienced.

Again, that's just one data point of 2014 vs 2015. You really can't draw general conclusion. Maybe I just got lucky or Kevin got unlucky. Or maybe Kevin is just a wild man behind the wheel! :)
 
SparkevBlogspot said:
Norton is correct in that you need to have lot more data to draw conclusions about 2014 vs 2015 in general. However, given that I drive down to "low" (1 mile remaining) few times and often down below 10 miles remaining as well as hundreds of DCFC (several times a week) and only got 0.3 kWh change from 18.4 kWh that it's supposed to be from factory, it seems my 2015 battery does quite well even with my usage pattern. My GOM still shows around 100 miles few times that I did charge to 100%. While I don't know how abusive Kevin is to his 2014, it'd be hard to top the level of use my 2015 has experienced.

Again, that's just one data point of 2014 vs 2015. You really can't draw general conclusion. Maybe I just got lucky or Kevin got unlucky. Or maybe Kevin is just a wild man behind the wheel! :)
To add a little more to the discussion I offer the following:

For my 2014 Spark EV: (I drive in L and mainly in town)
Miles traveled: 3369
Number of charging sessions (full charge): 58
Avg miles/kWh: 5.58
Avg full charge battery capacity: 18.59 kW
GOM at full charge: Min: 98 Avg: 105 Max: 112

For my 2015 Spark EV: (My wife drives in D in town and on the freeway)
Miles traveled: 5623
Number of charging sessions (full charge): 70
Avg miles/kWh: 5.32
Avg full charge battery capacity: 17.78 kW
GOM at full charge: Min: 86 Avg: 97 Max: 104

Note: All data was collected starting in March 2016 and continues to be collected. I plan to continue collecting data through next year to get a better picture of battery capacity degradation for both cars.
 
kevin said:
evboy said:
I'm looking at a 2014 spark ev. u can buy them on carmax for 10500. My question is i only drive about 3500 miles a year. i was concerned, if i buy a 2014 spark with a123 batteries in them, they wont have a replacement, since its not a LG battery like 2015. Should i quit worrying since 10 years of driving is only adding 35000 miles to it? will my battery still hold a good range with only 35k added or will it lose alot of range anyway after 10 years because the battery aged 10 years. If I by a used one with 15k miles on it, it will only have 50k on it in 2027. What do u guys think. Should i buy a 2015 instead which cost more but has a LG battery in it. Will the battery degrade with age even if I dont put alot of miles on it? Will a 2014 spark ev with 50k miles on it today have the same range as a 2014 spark ev with 50k miles on it in 2027 ?

Also, the Nissan leaf has completely collapsed in resale value. U can buy a 2013 for 6500. do u see the spark dropping like that or is it exclusive to the leaf since they didnt use liquid cooling on their battery.

This is the capacity of my 2014 Spark EV over 3 years.

The graph was created from readings off the energy screen after discharges of greater than 50%.

I was disappointed at the level of degradation.

kevin
SparkBattery.png

As I understand it, A123 cell (LFP chemistry) degradation is completely based on calendar life with minimal impact by cycle life. Although a 18.4% degradation is quite excessive and more than mine. Do you have an updated graph?

I bought my '14 Spark EV (w/o DCFC, build date 09/13), in 04/15 after sitting on the lot for 500 days. At 21000 miles, the lowest capacity I've seen was around 16.5 kWh (but this amount varies significantly as you know).

Some questions that may impact degradation:
- Do you leave your car outside or garaged?
- Do you leave your vehicle plugged in when not driving? (sitting at high SOC)

For me:
- My vehicle is typically garaged, but outside in scorching desert heat while at work (I also get workplace charging so that helps with the battery TMS)
- I typically only plug in at work, with the occasional home charging so my vehicle is almost NEVER sitting at a high SOC which helps fight degradation a lot. I know GM recommends plugging in your vehicle while not in use (especially for the volt) to keep the TMS active but I felt it was worth it to keep SOC lower with TMS off than leaving the TMS on for summer heat/winter cold especially in a garaged vehicle in SoCal weather.
 
Jedi2155 said:
....

>As I understand it, A123 cell (LFP chemistry) degradation is completely based on calendar life with minimal impact by cycle life. Although a 18.4% >degradation is quite excessive and more than mine. Do you have an updated graph?

>I bought my '14 Spark EV (w/o DCFC, build date 09/13), in 04/15 after sitting on the lot for 500 days. At 21000 miles, the lowest capacity I've seen was >around 16.5 kWh (but this amount varies significantly as you know).

>Some questions that may impact degradation:
>- Do you leave your car outside or garaged?
>- Do you leave your vehicle plugged in when not driving? (sitting at high SOC)

For me:
- My vehicle is typically garaged, but outside in scorching desert heat while at work (I also get workplace charging so that helps with the battery TMS)
- I typically only plug in at work, with the occasional home charging so my vehicle is almost NEVER sitting at a high SOC which helps fight degradation a lot. I know GM recommends plugging in your vehicle while not in use (especially for the volt) to keep the TMS active but I felt it was worth it to keep SOC lower with TMS off than leaving the TMS on for summer heat/winter cold especially in a garaged vehicle in SoCal weather.
Afraid I didn't get any more data - the lease ended just a few days after the graph.

My usage was pretty much the same as yours. I would usually charge at work. That did mean that the battery was often at high SOC from 11AM to about 6PM in the heat of the day as I usually charged in the morning although I would think that it is not as hot in the Bay area than in SoCal.

In the summer the car usually stayed outside at night but in the winter my other car had to stay outside so i didn't have to warm the Spark up so much in the morning.

I didn't usually charge at home but when I did I tried to use the timed charging so that it only reached full SOC an hour or so before I needed it.

I only used 120v charging at home even though I did purchase the level 2 charger when I got the Spark - I found that the Spark was efficient enough that I could get all the charging I needed on level 1 - enough for about 70-80 miles during a night's charge. Admittedly I did usually set the charge rate to 12Amps.

kevin
 
Hi,

Here are a couple of other charts from the same data.

As expected the range at full charge decreased from 113miles down to 98 while the efficiency increased slightly from 5.7mi/kWh to almost 5.9mi/kWh.
I expect much of that was the tires wearing. I changed the front tires at 18000 miles but the rears were still the original at the end. After replacing the fronts I expect the efficiency to decrease significantly but I didn't see any significant change.

During warm days in the summer I even saw quite a few days where I had readings of about 8mi/kWh for round trip commutes of 25 miles.

kevin
SparkRange.png


SparkMikWh.png
 
Just shedding my insight here:

I AM a wild man behind the wheel. I average 3.5 mi/kWh (can't get enough of that 402 ft/lbs!). My SparkEV is a 2014 with 28,000 miles. I also live in Utah where the temps are very extreme (below freezing overnight in the winter). The car is always plugged in when not in use (120v at home, 240v at work). I always have temp control set to Auto at 71*F.

My Guess'o'Meter predicts 50 miles minimum and 70 miles maximum at full charge. Your mileage may vary (literally!), but my take away is that my a123 battery has suffered degradation at only 28,000 miles. Although, that could just be my driving style.
 
JeffTAC4 said:
Just shedding my insight here:..... My SparkEV is a 2014 with 28,000 miles...... but my take away is that my a123 battery has suffered degradation at only 28,000 miles...
Data, or it's just an opinion! :p

But it happens. We all know it. Every EV has it. Some just hide/mask it.
 
NORTON said:
Data, or it's just an opinion! :p

I don't have the know how to make graphs to grab data points as you have done in this thread (but I should probably look it up!). I am strictly basing this off of the fact that it was advertised at having an 82 mi range fully charged, where as my average range is only about 60 miles (70, driving conservatively).

Also, I am not complaining or upset if battery degradation has occurred. Of course I know that it's an inevitable reality with any current energy storage medium. I still get way more mileage out of a charge then I ever need on a day to day basis.

This does, however, beg another question that has already been discussed and speculated upon. With an 8 year warranty on the battery, will Chevy replace units that have become heavily degraded without having actually failed?
 
Does anyone know how Chevy determines degradation for a warranty replacement?

The data collected by Zoomit is substantial but shows a wide range of values for battery capacity. I doubt Chevy is going to drive your vehicle around for a month and come up with an average.

Maybe the answer is Chevy doesn't really know how they will measure degradation and are going to wing it?
 
doesnt the warranty say it covers more than 35% capacity loss. i read that somewhere. I know when I get close to the 8 years expiration, i will be at the dealership complaining about capacity loss and that i should get a new battery. let them figure it out. by that time batteries will be 100 dollars per kwh so thats 2100 plus install if i have to pay for it myself. one question, if the batteries lose capacity with age and not really cycling as someone here posted, arent the a123 packs that r sitting in storage now going to be bad packs since they will be sitting around for 8 years. i dont c how they can sell or install those.
 
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