RSC
Posts: 71
Joined: Thu Sep 20, 2018 5:45 am

Sudden loss of capacity

Wed Nov 18, 2020 8:35 am

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.
Ray
2015 Spark EV 1LT, DCFC

SparkE
Posts: 418
Joined: Tue Sep 06, 2016 1:18 am
Location: SF Bay Area (San Jose, CA)

Re: Sudden loss of capacity

Thu Nov 19, 2020 1:00 pm

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.

RSC
Posts: 71
Joined: Thu Sep 20, 2018 5:45 am

Re: Sudden loss of capacity

Thu Nov 19, 2020 2:17 pm

SparkE wrote: 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.
Ray
2015 Spark EV 1LT, DCFC

RSC
Posts: 71
Joined: Thu Sep 20, 2018 5:45 am

Re: Sudden loss of capacity

Tue Nov 24, 2020 2:48 pm

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.
Ray
2015 Spark EV 1LT, DCFC

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