Sudden loss of capacity

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I've been tracking my capacity with Torque Pro, and it's been holding steady at 15.2 kWh since March of 2020. Range on a full charge has been running around 68 miles. A little low, but I don't have the original tires on it, and my usual trips are downhill on a full charge (so not much regen), then back uphill. If I do some uphill then downhill trips, the range goes up.

Today I was concerned that the GOM read 58 miles, so I did a Torque Pro reading, and it came up 13.6 kWh! Is this real? What happened? All the cell voltages look normal.

I did do something out of the ordinary on Monday. I drove the car about 16 miles downhill, to the New Melones Tuttletown Recreation Area, using about 0.2 kWh, then left it for a couple of hours while I went for a walk. I had been meaning to try out the L2 charging station there, so I plugged the car in for a few minutes after my walk just to see whether the charger was operational. It seemed to work fine, although I didn't wait for a full charge before unplugging and driving home about 16 miles uphill.

On arriving home, I plugged in and let it charge overnight on Rate and Departure Time. It didn't have time to get to a full charge but the next morning (Tuesday) I went out for groceries and plugged in when I got home. I wasn't concerned about a low range display, because as I said, it didn't have a full charge. This morning (Wednesday) was a full charge, showing 58 miles of range and 13.6 kWh.

Any ideas? I suppose I'll just drive as usual for a while and see whether the range comes back up.

 

[SparkE]

1) cold weather. This can affect your capacity (if it is < 50 degrees - a LOT if it is < 30 degrees)

2) You have Torque Pro. Fill to full. Drive it down a bit (?10 %? ?20%?). Look at the voltages of all of the cells in the battery. Is one of them much lower than the others? If so, you have a problem cell.

 

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2) You have Torque Pro. Fill to full. Drive it down a bit (?10 %? ?20%?). Look at the voltages of all of the cells in the battery. Is one of them much lower than the others? If so, you have a problem cell.

Thank you very much. I'll try number 2 and post what I see.

Update 11/20/2020:
We went out for groceries, and returned with 80% SOC. I plugged in the OBD2 reader immediately on our return, and found that all the cell voltages were either 3.99 or 4.00 volts. I guess that's good in that I don't want to deal with taking the car in right now, and I really don't think my local Chevy dealer knows anything at all about EVs. Battery temperature was 57 degrees and coolant and air temperatures were 54 degrees. Capacity still at 13.6 kWh.

I think I'll go for a longish drive on Monday starting in the uphill direction and see whether that has any effect. After that I suppose I'll wait for my monthly diagnostics report. The reduced capacity is disappointing, but has no impact on me personally with the the short trips that I'm using the car for.

 

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As I said I was going to, I took a longish drive uphill yesterday. I went for a walk for a couple of hours, then did a Torque Pro check. All of the cell voltages were 3.87 volts. There was one cell that flickered back and forth between 3.87 and 3.88, but settled down at 3.87. Torque indicated 62.7% SOC (DIC). The car's energy display was a little inconsistent in showing 40% used. GOM indicated 30 miles left, which went down to 28 miles after a little uphill driving, then up to 42 miles on arriving home.

I checked the capacity a few minutes ago, and it was still 13.6 kWh (actually 13.567 compared to 13.600 before). I'll check the capacity tomorrow after a full charge. I didn't have time to get to a full charge last night on my Rate and Departure Time schedule at 8 amps. Also my wife made a quick trip to the post office. I suspect the indicated capacity is still going to be 13.6 kWh.

 

[Kermit]

My capacity dropped quite a bit this year and I haven't been driving much. I've only seen the capacity rise once and that was during the hot summer. I don't think you'll get the capacity back. The question is, Will the GOM range that you can get out of it still work for you?

 

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Still 13.6 kWh.

... Will the GOM range that you can get out of it still work for you?

Absolutely. I think that I've gone below 50% SOC on only maybe 3 occasions. We have a Toyota Highlander for road trips and camping, but it goes weeks without being used. And there's an Enterprise Rent-A-Car location 2 miles from home.

I'll continue to report capacity monthly in another thread.

 

[ZNuts]

The 2016 I bought in August used to show 80-85 miles range and now shows 60-68. I garage the car and the weather here in the Pacific NW is mild with daytime high in the high 40s-low 50s now.

Yup, it's a bit of concern but I'll see what the next summer brings. I do have a ICE car that I take for longer trips but this makes me think about maybe upgrade to a Bolt sooner.

 

[SparkE]

The 2016 I bought in August used to show 80-85 miles range and now shows 60-68. I garage the car and the weather here in the Pacific NW is mild with daytime high in the high 40s-low 50s now.

Yup, it's a bit of concern but I'll see what the next summer brings. I do have a ICE car that I take for longer trips but this makes me think about maybe upgrade to a Bolt sooner.

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A battery pack temp in the low 50s will lower your range. I used to have 95 consistently on the GOM at full charge this summer (I generally use the car "around town", my fastest speed around 45 mph on expressways). With winter here, night-time temps in the high 30s or low 40s, daytime temps around 55-60, I am getting about 75-80 on the GOM. And I don't use the heater unless the car is plugged in.

 

[zzzzzzzz]

It seems like almost EVERYONE has had a sudden drop of capacity this year. Could this just be due to faster driving, due to less traffic? It's not like GM can send a mass update to all the cars that can slowly retard battery capacity. I'm stumped.

 

[TheLondonBroiler]

I'm going off memory (heaven help us all), but I'm pretty sure there have been several instances of members discovering approximately 1kwh was no longer available. I know I've had that experience and believe I shared it. The battery degradation threads are four plus years old and essentially have established in the past two years, that Spark battery degradation continues to be significant and universal.

 

[SparkE]

It really makes me think that GM "really got it right" with the Bolt EV and its battery. Reports of multiple vehicles with over 100K mileage, maybe 10% max battery degradation over 3.5 - 4 years. My Sparky has around 15 kWh (out of an original 18.5) after 4 years and 20k miles ; that's 20%. And I consider myself lucky! (But I also only have about 20k miles on the car - it really is our "around town" vehicle, for trips < 80 miles round-trip - which is most of our driving when all is said and done.)

A Bolt can be found used now for under $15k (in the SF area at least). With incentives (if you must have new) there are reports of 2020 Bolts being sold for under 28K, not counting the tax incentives or govt rebates. The Spark will do fine for years to come for us (2 car family) but I might replace it with a Bolt when the prices drop under $10k. That would relegate our gasmobile to usage only for trips over 200 miles - maybe twice or four times a year (or times when both of us need to use a car at the same time). She already only gets driven about 3500 miles a year - with a Bolt, it would probably drop down to 1500 miles (trips to SoCal or Tahoe, basically). At the moment, drives to the north SF Bay and Sacramento and down to Monterey bay are done in the gas car - that would end if I had a Bolt (I'd need a 20-25 minute charge stop for my trips to Sacramento, but what the hay).

 

[TheLondonBroiler]

I'm going off memory (heaven help us all), but I'm pretty sure there have been several instances of members discovering approximately 1kwh was no longer available.

Found it. According to torque pro readings 0.8kwh was lost in a two week time frame. Keep in mind it was when it was getting cold.... just like now.

https://www.mychevysparkev.com/forum/viewtopic.php?f=7&t=4464&p=22620#p22620

 

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Got the monthly OnStar diagnostics report today. Supposedly everything is fine, but the GOM still estimates a range of 60 miles.

 

[user 1908]

I took a suggestion from this forum, and have been running my battery to 20 percent before charging.

If others like me have driven a lot less due to COVID, it appears exercisong the battery lIke that will restore some capacity. At one point Torque Pro showed 13.4; after doing it three times, it’s back up to 14.0.

 

[RSC]

I took a suggestion from this forum, and have been running my battery to 20 percent before charging.

If others like me have driven a lot less due to COVID, it appears exercisong the battery lIke that will restore some capacity. At one point Torque Pro showed 13.4; after doing it three times, it’s back up to 14.0.

Thanks. I might try that. This would be a good time of year, while the weather is still cool. I'm reluctant to leave the car unplugged for long when the weather is really hot.