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.