Battery Degradation vs Battery Limited Warranty

[MrDRMorgan]

The problem with GM is, they won't give you the number your battery has to hit to qualify for the warranty. Is the calculation for degradation based on a 21kWh battery for a 2016 model? Mine suddenly started dropping this summer, now it's down to 13.5 according to Torque Pro.

I am using 19 kWh as being a full capacity new battery. Therefore, 60% is 11.4 kWh. I am currently measuring a TorquePro value of 14.1 kWh at about 32k miles.

 

[SparkE]

The 2014 is "around" 21 kWh. The 2015 and 16 had a different battery supplier than the '14s, and are "around" 18.5 kWh.

65% of 21 is 13.65 (2014)

65% of 18.5 is 12.025 (2015)

60% of 18.5 is 11.1 (2016)

 

[rtaite]

The 2014 is "around" 21 kWh. The 2015 and 16 had a different battery supplier than the '14s, and are "around" 18.5 kWh.

65% of 21 is 13.65 (2014)

65% of 18.5 is 12.025 (2015)

60% of 18.5 is 11.1 (2016)

Well, I don't think it is quite as simple as you're saying. The 2014 battery was rated at 21.4 KWH with only 17.3 KWH usable which comes from here: https://www.gm-volt.com/attachments/slide5-jpg.164190/

That means they have intentionally crippled the battery to only reach 80.8% of its potential capacity. Some reviewers have computed the actual number to be 91% of potential capacity -- this is obviously a zealously guarded trade secret. If you take that into consideration, then 65% of "new" would be 11.245. On the other hand, GM could simply provide a "software update" to release the 19.2% of the battery which is crippled and would probably yield another 2 to 3 KWH of capacity to give you 2 to 3 more good years before you decide to junk the car. Chevrolet/GM might also provide preferential pricing to those who want to convert to the 2015/16 battery since I expect the street price of lithium ion battery packs will be even cheaper than it is now.

I am betting that a software update to provide us with extra range (i.e., the 19.2% they crippled given back to us) will be available in 2022.

Any thoughts/bets?

 

[Kermit]

From my torque pro readings the individual cells are charging to about 98% their max voltage. I doubt their is any hidden capacity available on our cars.

 

[Planerench]

So after chatting with GM on my phone with texts, I set up another appointment with the dealership via a local Customer Experience Representative. The same shop manager told the rep there is no "capacity test" and if there is a problem the car will throw a code. My next call will be to the State Attorney General I think. Perhaps I can get some traction there. The battery capacity pencils out to 12.5 pretty consistently.

 

[TheLondonBroiler]

Thanks for the update. Hopefully the Mothership can help the dealership clowns sort it out..... although nowadays I wonder if the majority of the Mothership personnel, might actually be clowns...

 

[zzzzzzzz]

So, battery degradation has hit a low point yesterday, at 13.16 kW for 71.12% (below). I'm right at 60k miles now on the 2016 model; outside temperature this morning was at 35F in Portland. I'm not usingTorquePro, just taking snaps from the main display. Don't mind the sporadic date logging, as I've just taken random data samplings as of lates:

Date - Driving % - Climate % - Energy Used (kW) - Total (kW) - % from 18.5 (kW)
5/1/19 - 23 - 0 - 3.7 - 16.09 - 86.96%
1/7/20 - 25 - 1 - 3.9 - 15.00 - 81.08%
1/8/20 - 24 - 1 - 4 - 16.00 - 86.49%
1/15/20 - 25 - 2 - 4.2 - 15.56 - 84.08%
1/22/20 - 25 - 2 - 4.2 - 15.56 - 84.08%
2/10/20 - 24 - 0 - 3.7 - 15.42 - 83.33%
3/5/20 - 25 - 0 - 3.7 - 14.80 - 80.00%
6/24/20 - 22 - 0 - 3.1 - 14.09 - 76.17%
6/29/20 - 23 - 0 - 3.2 - 13.91 - 75.21%
7/7/20 - 23 - 0 - 3.3 - 14.35 - 77.56%
8/5/20 - 22 - 0 - 3.2 - 14.55 - 78.62%
8/18/20 - 23 - 0 - 3.2 - 13.91 - 75.21%
11/3/20 - 29 - 0 - 4.1 - 14.14 - 76.42%
11/16/20 - 28 - 1 - 3.9 - 13.45 - 72.69%
11/20/20 - 29 - 3 - 4.3 - 13.44 - 72.64%
11/30/20 - 54 - 3 - 7.5 - 13.16 - 71.12%

Thoughts? Regression line doesn't look great, as it looks like it has deteriorated rapidly in 2020 (almost 16%!)

 

[MrDRMorgan]

So, battery degradation has hit a low point yesterday, at 13.16 kW for 71.12% (below). I'm right at 60k miles now on the 2016 model; outside temperature this morning was at 35F in Portland. I'm not usingTorquePro, just taking snaps from the main display. Don't mind the sporadic date logging, as I've just taken random data samplings as of lates:

Date - Driving % - Climate % - Energy Used (kW) - Total (kW) - % from 18.5 (kW)
5/1/19 - 23 - 0 - 3.7 - 16.09 - 86.96%
1/7/20 - 25 - 1 - 3.9 - 15.00 - 81.08%
1/8/20 - 24 - 1 - 4 - 16.00 - 86.49%
1/15/20 - 25 - 2 - 4.2 - 15.56 - 84.08%
1/22/20 - 25 - 2 - 4.2 - 15.56 - 84.08%
2/10/20 - 24 - 0 - 3.7 - 15.42 - 83.33%
3/5/20 - 25 - 0 - 3.7 - 14.80 - 80.00%
6/24/20 - 22 - 0 - 3.1 - 14.09 - 76.17%
6/29/20 - 23 - 0 - 3.2 - 13.91 - 75.21%
7/7/20 - 23 - 0 - 3.3 - 14.35 - 77.56%
8/5/20 - 22 - 0 - 3.2 - 14.55 - 78.62%
8/18/20 - 23 - 0 - 3.2 - 13.91 - 75.21%
11/3/20 - 29 - 0 - 4.1 - 14.14 - 76.42%
11/16/20 - 28 - 1 - 3.9 - 13.45 - 72.69%
11/20/20 - 29 - 3 - 4.3 - 13.44 - 72.64%
11/30/20 - 54 - 3 - 7.5 - 13.16 - 71.12%

Thoughts? Regression line doesn't look great, as it looks like it has deteriorated rapidly in 2020 (almost 16%!)

I would love to have your results. I have 32438 miles on my 2016 Spark EV and my current battery capacity, as measured today using TorquePro, is 13.7 kwh. What is of more concern is my battery capacity has dropped from 14.5 kwh at 31346 miles on 9 Aug to 13.7 kwh at 32438 miles on 1 Dec. What is interesting is my GOM range is still 85 miles. At this degradation rate, I will hit the warranty replacement point sometime next year.

This rapid drop in capacity makes me wonder if reduced driving due to Covid restrictions has had an impact on battery capacity health.

 

[zzzzzzzz]

13.7 kW? That does seem low for only 32k miles. At 32k miles I was still getting about 16-17 kW approximately. I wonder why the sudden drop off for you.

For me, I think there could be a few factors that I'm trying to consider:

1) I am "unfortunately" not working remotely anymore, so I drive into the office every day. And during this pandemic the freeways and roads have been relatively free of traffic, so my commute has been very fast.
2) I have an open recall for range estimation. Could that affect it?
3) I have 195/55R15 front tires that are 2 years old now. Could wear affect it? I also need to inflate the tires a bit, as they're about 34-32 PSI now, cold.
4) Car has been parked outside now, since last September. I don't think the cold affects it too much as the decrease in capacity has been consistent, even during the summer months.
5) I have a subwoofer that was always ON, no remote on, but since disconnected it completely just last week. Doesn't appear to affect range much.

What else?

 

[TheLondonBroiler]

13.7 kW? That does seem low for only 32k miles.

What else?

Pretty much par for the course. Time and usage both appear to be merciless at removing capacity from Spark battery packs. We all charge to 100% for the most part, and that impacts cycle life. This only snowballs as you have less range, you need to charge to a higher SOC, furthering the problem. Text book definition of a vicious cycle.

 

[SparkE]

13.7 kW? That does seem low for only 32k miles.

What else?

Pretty much par for the course. Time and usage both appear to be merciless at removing capacity from Spark battery packs. We all charge to 100% for the most part, and that impacts cycle life. This only snowballs as you have less range, you need to charge to a higher SOC, furthering the problem. Text book definition of a vicious cycle.

I, myself, rarely charge past 85%. And I don't charge when it is hot. During the summer, I used to plug in the Spark in the early morning when I get up, when the pack is at its coolest. Now, I use departure timing, and have it set to me leaving (being at 100%) at 10:30 in the morning, so all I have to do is unplug it around 9 a.m. I don't know if it has done any good or not, but it is free to simply pay attention and it takes maybe 30 seconds in the morning. And I still have over 15 kWh in the battery.

But then, I rarely drive it over 40 miles in a day, so I can do that. When I *know* I am going to drive over 50 miles, it charges overnight to 100%. Probably once every 2-3 months in normal times - not once since April of this year.

 

[user 1908]

I took a suggestion from one of the other posts on here, and I’m running my battery down below 30% before recharging. My experience is my battery went from 13.4 to 14.0 after doing it three times.

 

[zzzzzzzz]

Still no major improvements on my side. I pumped up the tires to 40PSI 5 days ago and still average 13.26 kWh capacity since then. I have been parking the car outside since last September 2019 due to an addition of a Fiat Abarth 500 taking up that garage space now, so I think as a test, for tonight for tomorrow and Wednesday's commute I'll switch those spaces and see if parking in the garage makes any noticeable difference.

Frustrating. This weekend I've been looking at i3's and Bolts. If the degradation keeps up, I'd rather get rid of it now. It's been a good 4-5 years owning the Spark, and no complaints other then this range issue (potentially).

 

[TheLondonBroiler]

Still no major improvements on my side. I pumped up the tires to 40PSI 5 days ago and still average 13.26 kWh capacity since then.

see if parking in the garage makes any noticeable difference.

If the degradation keeps up, I'd rather get rid of it now. It's been a good 4-5 years owning the Spark, and no complaints other then this range issue (potentially).

I think if you're expecting more than half a kilowatt, you're going to be disappointed. My Spark was reading 13.3kwh, but after taking it on a 1,500 mile trip over the course of a week, with dozens of fast charges, it was giving a reading of 13.7kwh.

If degradation keeps the same rate of degradation, "technically" you should be eligible for a new battery @ 10.8kwh (in your 2016). Will the Spark meet your needs (or many owners for that matter) at that point though, I wonder? If you're surrounded by fast chargers, it's more likely, but if not....

Regardless of what you decide to do with it, best of luck.

 

[zzzzzzzz]

I think if you're expecting more than half a kilowatt, you're going to be disappointed. My Spark was reading 13.3kwh, but after taking it on a 1,500 mile trip over the course of a week, with dozens of fast charges, it was giving a reading of 13.7kwh.

If degradation keeps the same rate of degradation, "technically" you should be eligible for a new battery @ 10.8kwh (in your 2016). Will the Spark meet your needs (or many owners for that matter) at that point though, I wonder? If you're surrounded by fast chargers, it's more likely, but if not....

Regardless of what you decide to do with it, best of luck.

LondonBroiler, looking at your signature got me curious on my own lifetime efficiency, and at 60,426 miles on the Chevrolet app its at a dismal 4.0 mi/kWh. I don't know what I'm expecting, just hate this sudden drop of capacity in the last year. If the capacity stayed within about .5kWh per year, I'd be fine with that, but it's much worst. What I have been pondering is just trading in the Spark for...maybe a 2020 Bolt? There has to be lots of inventory and plenty of sales now at year end. If I can get 5k in trade-in for my Spark, I'd be happy with that.

I see you have a Bolt also, and at 70k miles in about a year's time? :shock: How is the Bolt compared to the Spark?

 

[TheLondonBroiler]

If the capacity stayed within about .5kWh per year, I'd be fine with that, but it's much worst. What I have been pondering is just trading in the Spark for...maybe a 2020 Bolt? There has to be lots of inventory and plenty of sales now at year end. If I can get 5k in trade-in for my Spark, I'd be happy with that.

I see you have a Bolt also, and at 70k miles in about a year's time? :shock: How is the Bolt compared to the Spark?

I believe my degradation has slowed only due to not driving it much. I lost ~0.3kwh in the last 18 months with probably 3,000 miles of driving.

I like the Bolt a lot, it's a lot more refined, it's obviously bigger and has more features, compared to the Spark. The only things I dislike that I think could easily be improved upon and are worthwhile mentioning: fast charge speed/curve (2020 minimally better); seats aren't particularly comfortable; and the suspension is a bit too rough for my liking (a rear multi-link would be a huge improvement).

All in all, I think the Bolt is a better car, still "the most EV for your money," imo. There are "better" options, but all things considered, it's tough to beat.

 

[zzzzzzzz]

I believe my degradation has slowed only due to not driving it much. I lost ~0.3kwh in the last 18 months with probably 3,000 miles of driving.

I like the Bolt a lot, it's a lot more refined, it's obviously bigger and has more features, compared to the Spark. The only things I dislike that I think could easily be improved upon and are worthwhile mentioning: fast charge speed/curve (2020 minimally better); seats aren't particularly comfortable; and the suspension is a bit too rough for my liking (a rear multi-link would be a huge improvement).

All in all, I think the Bolt is a better car, still "the most EV for your money," imo. There are "better" options, but all things considered, it's tough to beat.

Thanks, good to know on the Bolt. Ideally I can find a used one at under 30k miles for around 13k and I'll buy. Or a new one at 20k.

In any case, I've just scheduled an appointment with the dealership to diagnose the battery capacity. There's a $150 diagnosis fee and if they find the battery needs to be serviced under warranty, they will forgo the charge and complete the warranty work. I bet money that the battery is "in perfectly good health and is on the correct degradation cycle" and they take my $150. At least it'll be documented in their system that the capacity is at 13 kWh or whatever so when next year comes around and I'm at 12 or 11 kWh they can see the exponential decline and will have to replace the battery.

We'll see what happens by next week.

 

[NORTON]

In any case, I've just scheduled an appointment with the dealership to diagnose the battery capacity. There's a $150 diagnosis fee ....I bet money that the battery is "in perfectly good health ... and they take my $150. At least it'll be documented ....

Sounds like a lot of bother and $150 for 'documented'.
Why not wait for warmer weather and see how your numbers look then?
You have the 8yr - 100k mile period to dik with this...

 

[zzzzzzzz]

Sounds like a lot of bother and $150 for 'documented'.
Why not wait for warmer weather and see how your numbers look then?
You have the 8yr - 100k mile period to dik with this...

I took an average of my readings per year between 2018 and 2020 and did a line prediction for 2021-2024, and at 2024 I could expect to be at 8.09 usable capacity for 36.03 miles when the warranty should be 11.04 kWh for a range of 49.2 miles (40% of 18.2kWh). I'm going to show this summary and my detailed log to the dealership, and "express" my unhappiness and major concern of the range of the vehicle thus far as well as what may happen in the next few years.

Desc - 2016 - 2018 - 2019 - 2020 - 2021 - 2022 - 2023 - 2024
kWh - 18.4 - 16.98 - 15.71 - 13.99 - 12.57 - 11.08 - 9.58 - 8.09
Miles - 82 - 75.67 - 70.01 - 62.35 - 56.02 - 49.36 - 42.69 - 36.03

We own both a Spark and Volt, so hopefully they see that I'm a diligent Chevrolet vehicle owner and be willing to help.

 

[TheLondonBroiler]

Sounds like a lot of bother and $150 for 'documented'.

I'm going to show this summary and my detailed log to the dealership, and "express" my unhappiness and major concern of the range of the vehicle thus far as well as what may happen in the next few years.

We own both a Spark and Volt, so hopefully they see that I'm a diligent Chevrolet vehicle owner and be willing to help.

Agree with Norton, wouldn't waste my time at the dealer. They're going to tell you to come back when you have a real warranty claim and maybe also that they believe degradation may not be linear..... Dude, trust me, I've got a Spark and Bolt, with the same degradation and a low range issue respectively, GM doesn't care until you have something that forces their hand.... and even then, you'll have to kick and scream and probably still have to go to court, or threaten to.