GOM (estimated mileage) and battery degradation

[SparkE]

Visited a friend recently, he plugged me in to his company's L2 network while we ate lunch (a *very* long lunch) and went to 'full' for the first time in .... 4 months? Temp was around 78 degrees, and I was very happy to see that my 2015 Spark EV had a full range of ... 106 miles. Yes, it's based on driving habits and temp, however my original 2016 (the one my wife totaled) almost never got over 110, so I am very happy. The car is over 4 years old and still has most of its battery capacity. I think it is because *I* don't charge to full very often (generally between 75-80%).

DrMorgan, have your experiments on 'not charging to full' revealed less battery capacity loss, or is the battery degradation still fairly linear on your two?

 

[MrDRMorgan]

SparkE - Interesting results so far.

2014 Spark EV - 16.2 kWh at 17813 miles and 15.7 kWh at 20118 miles.
2016 Spark EV - 15.6 kWh at 17874 miles and 15.5 at 23926 miles. A lot of DCFC charging to 90% is included too.

This week both cars gave me a full-charge GOM of 92 miles.

 

[SparkE]

DrMorgan, you have been tracking the battery capacity of your vehicles for a while and (i think) even have posted details of battery degradation in your 2 sparks.

I remember that you posted a while ago that you would experiment on 'not charging to full' - have you done that and has it revealed less (or 'slower') battery capacity loss, or is the battery degradation still fairly linear on your two?

I realize that YOU living in the central valley (HOT!) and me living near San Jose (temperate, usually, but not THIS year for some bizarre reason - 104F yesterday!) that temperature can have an effect on battery longevity. When it's hot, I don't charge - I set an alarm and wake up early (sometimes 5 a.m.) to plug in the car when the battery pack has cooled. If I had a 'regular schedule', I'd just use "departure timing", set it to an hour or two *after* I planned on leaving, and plug it in all night and just unplug in the morning.

 

[MrDRMorgan]

SparkE -

My 2014 Spark EV has been charged using delayed timing so I charge overnight using the L1 EVSE that came with the car. I set my target finish time so I will have 80% charge at 8 am. A few times I have let it go to 100%. At 17813 Miles on 4 April 19, my measured battery capacity was 16.2 kWh. At 20118 miles on 11 Sep 2019 my measured battery capacity was 15.7 kWh. I lost 0.5 kWh in about 2300 miles. The graph shows battery capacity stays linear for a while, drops by 0.1 kWh and continue flat for a while more and drops again.

My 2016 Spark EV has been charged using an L2 EVSE (3.3 kWh) and delayed timing. but, many times I needed 95%+ for a trip so I charged to 99%. In addition, I have had many DCFC sessions where I cut off at 92%. I lost 0.1 kWh in about 6100 miles.

Both cars currently give me a full-charge GOM value of 92-95 miles. The current battery capacity in the 2014 is 15.6 kWh and the 2016 is 15.5 kWh.

Lately, my garage temperature in the evening has been running about 95 deg. F and remains fairly warm overnight. I will continue tracking the battery capacity to see what effect cooling weather will have on the degradation rate for each vehicle.

 

[RSC]

I started tracking my battery capacity (Torque Pro) on a monthly basis:

Date Mileage Capacity (kWh)
5/5/2019 18601 16.1
6/1/2019 18905 15.9
7/3/2019 19259 15.9
7/13/2019 19425 16.2
8/1/2019 19669 16.3
9/1/2019 19878 16.4

I haven't succeeded in using BBCode to format this as a table.

This is almost all L1 charging at 8 amps, maybe a couple of times at 12 amps and one L2 session to get the car home from the dealer (16K miles, September 2018). As you can see, I don't drive much. The car is plugged in almost all the time, set to Rate and Departure charging. On the PG&E EV-A plan, this is almost all at night. I'm retired, so the car doesn't sit in a parking lot for very long. Sometimes when I return from a drive on a hot day I'll charge Immediate for 5 or 10 minutes just so battery cooling will kick in (unplug, then plug back in within 10 seconds).

The GOM currently shows 72 miles. I don't have LRR tires and live on a hill, so I don't get much regen starting out from full.

There seems to be a recent upward trend in capacity. It will be interesting to see what the capacity is on Oct. 1.

 

[MrDRMorgan]

I started tracking my battery capacity (Torque Pro) on a monthly basis:

Date Mileage Capacity (kWh)
5/5/2019 18601 16.1
6/1/2019 18905 15.9
7/3/2019 19259 15.9
7/13/2019 19425 16.2
8/1/2019 19669 16.3
9/1/2019 19878 16.4

I haven't succeeded in using BBCode to format this as a table.

This is almost all L1 charging at 8 amps, maybe a couple of times at 12 amps and one L2 session to get the car home from the dealer (16K miles, September 2018). As you can see, I don't drive much. The car is plugged in almost all the time, set to Rate and Departure charging. On the PG&E EV-A plan, this is almost all at night. I'm retired, so the car doesn't sit in a parking lot for very long. Sometimes when I return from a drive on a hot day I'll charge Immediate for 5 or 10 minutes just so battery cooling will kick in.

The GOM currently shows 72 miles. I don't have LRR tires and live on a hill, so I don't get much regen starting out from full.

There seems to be a recent upward trend in capacity. It will be interesting to see what the capacity is on Oct. 1.

I saw an increase in capacity on my 2016 Spark EV too. It rose from 15.5 to 15.8 and then slowly came back down to 15.5.

 

[dmanning68132]

I'm really interested in the best way to do this. I have 2 Spark EVs - a 2014 with only 5000 miles on it that I've had for 2 years, and an 2016 with 23000 miles on it I got last month. I know there's a difference between the 2014 and 2016 model, but on these colder fall days, the 2014 is topping out at 56-60 miles at "full"; in the summer it would hit the low 70s. The 2016 would typically top out around 85, and it's down to mid 70s right now. Caveat on both - they sit outside, and I'm not driving these cards 40+ miles per day - they're city commuters for me and my teen drivers. The concern, obviously, is on the 2014. When I bought it in 2017, it was as a Certified Chevrolet used car - with a 7-year warranty. The miles, and the price, made it a no brainer.

What I need to know - how can I calculate the battery degradation, and how do I set the charger to stop at 80% if that is indeed the way I should be charging it? These both just plug into 120v outlets, btw, although I've charged them at L2 an DCFC stations locally when they both were very depleted at the same time.

Thanks!

Dave

 

[Kermit]

To get my car to stop charging around 80% I have the charging set by departure time. I only charge via 120v at 8 amps so I don't have to hit any buttons before getting out of the car. I have the departure time set to 1pm and since I leave for work around 8AM that gets it to about 80% charged. I also have it set to charge less on Friday morning (departure time set to Noon) so after I drive it Friday it sits over the weekend at about 50% while unplugged. I plug it in Sunday night to charge to 80% for the week (if I forget to plug it in the 50% charge is more than enough to get me to work and back a couple of days).

I do charge to 100% about once a month because I have heard it allows the battery cells to balance.

Also if you ever need to charge immediately you just have to plug the cord in unplug it and plug it back in to bypass these settings.

As far as figuring out the 80% mark if you don't have an OBD2 reader and enginelink (ios) or torque pro (android) you could just get it to 8 bars on the battery meter.

Your location may change these charging suggestions though, if you live somewhere very hot or very cold you may want to leave it plugged in to allow the car to condition the battery at least on the days that are very cold or hot.

 

[MrDRMorgan]

To get my car to stop charging around 80% I have the charging set by departure time. I only charge via 120v at 8 amps so I don't have to hit any buttons before getting out of the car. I have the departure time set to 1pm and since I leave for work around 8AM that gets it to about 80% charged. I also have it set to charge less on Friday morning (departure time set to Noon) so after I drive it Friday it sits over the weekend at about 50% while unplugged. I plug it in Sunday night to charge to 80% for the week (if I forget to plug it in the 50% charge is more than enough to get me to work and back a couple of days).

I do charge to 100% about once a month because I have heard it allows the battery cells to balance.

Also if you ever need to charge immediately you just have to plug the cord in unplug it and plug it back in to bypass these settings.

As far as figuring out the 80% mark if you don't have an OBD2 reader and enginelink (ios) or torque pro (android) you could just get it to 8 bars on the battery meter.

Your location may change these charging suggestions though, if you live somewhere very hot or very cold you may want to leave it plugged in to allow the car to condition the battery at least on the days that are very cold or hot.

I found that each higher bar is illuminated when the charge level reaches 1% higher than the bar below it. For instance, at 70% charge, 7 bars will be illuminated. At 71% the eighth bar illuminates. This happens while adding or using battery capacity. You can use TorquePro to confirm this.

 

[MrDRMorgan]

For what it is worth, I went back through all of the battery capacity data I collected for the 2014, 2015 and 2016 Spark EVs I have owned or leased. Here is a summary of the battery degradation I have experienced:

2014 Spark EV 2LT (purchased as a used vehicle):
At 1.9 k miles the "calculated" battery capacity was 20.01 kWh
The average "calculated" battery capacity for the interval of 12.3k to 14k miles was 17.0 kWh
The most current "TorquePro" measured battery capacity at 20.8k miles is 15.6kWh.

2015 Spark EV 2LT with DCFC (leased):
At 2.2k miles the calculated battery capacity was 19.1 kWh.
The average "calculated" battery capacity for the interval of 24k to 26.8k miles was 15.9 kWh.

2016 Spark EV 2 LT with DCFC (purchased as a used vehicle):
The average "calculated" battery capacity for the interval of 7.7k to 10.0k miles was 17.7 kWh.
The most current "TorquePro" measured battery capacity at 25.9k miles is 15.2kWh.

It looks like it is not unreasonable to have an HV battery capacity of 15 kWh when the ODO hits 30k miles +/-.

 

[didget69]

Last night, I charged our 2015 Spark EV 2 LT at an EVGO station, and charged to 100%, with GOM showing 77 miles of range (50-degree temps last night).

Car has been in our hands since late 2016, when we purchased it as a 178 mile demo unit.
This is only the ninth time using L3/DC charging since we've owned the car. Each time on L3, we have waited until 100% is achieved.

We have primarily always charged at home on L1, and my wife plugs in the car at her office daily on their free L2 charger, always to 100%.

We have never stopped the charging at 80-90%, and have always let it stay on plug to 100% until ready to drive. 'Evie' is Now showing 23,206 miles, and 16.4kwh level on main pack.

YMMV.

Bryan

 

[MrDRMorgan]

Last night, I charged our 2015 Spark EV 2 LT at an EVGO station, and charged to 100%, with GOM showing 77 miles of range (50-degree temps last night).

Car has been in our hands since late 2016, when we purchased it as a 178 mile demo unit.
This is only the ninth time using L3/DC charging since we've owned the car. Each time on L3, we have waited until 100% is achieved.

We have primarily always charged at home on L1, and my wife plugs in the car at her office daily on their free L2 charger, always to 100%.

We have never stopped the charging at 80-90%, and have always let it stay on plug to 100% until ready to drive. 'Evie' is Now showing 23,206 miles, and 16.4kwh level on main pack.

YMMV.

Bryan

I did not have TorquePro when I was driving my leased 2015 Spark EV, so I calculated my battery capacity using the data on the Energy Information screen in the car. My calculations show I had 16.4 kWh at 23k miles. However, there was considerable variation in the calculated data points. But, I show 17.8 kWh at 18591 miles in June 2017 and 15.49 in March 2018.

Using TorquePro, my 2016 Spark EV had 15.8 kWh at 16449 miles on 13 Feb 2019 and 15.7 kWh at 23045 miles 16 Aug 19. My latest reading is 14.7 kWh at 27761 miles on 16 Jan 2020.

What I do notice is variations in the battery capacity data that track the battery temperature at the time the measurement was taken. Lower battery temperature tracks with lower battery capacity.

 

[didget69]

I'm just getting started with checking battery capacity after 3+ years & it's merely curiosity for me.

I feel pretty confident that GM Engineers designed the packs to handle 100% charge at each 'fill-up' - Time will tell!

Bryan

 

[Kermit]

I'm just getting started with checking battery capacity after 3+ years & it's merely curiosity for me.

I feel pretty confident that GM Engineers designed the packs to handle 100% charge at each 'fill-up' - Time will tell!

Bryan

Are you measuring with Torque Pro to get your capacity?

 

[Sam12345]

14kwh at 51000 miles

 

[Sam12345]

New battery pack : $4300

https://www.gmpartsclub.com/oem-parts/gm-battery-tray-23348215

{ edited by mod to make it obvious it is $4300 }

 

[Sam12345]

New battery pack : $4300

https://www.gmpartsclub.com/oem-parts/gm-battery-tray-23348215

.
Went all the way to checkout looks like $300 for shipping but no mention of a core charge ...

 

[NORTON]

Recent data points taken from the energy info page:

Mi. - -date - -displayed values - -calculated cap.
_________________________________________________
83884 8-10-20 94% 15.9 16.91
83977 8-12-20 63% 11 17.46
84081 8-14-20 75% 12.3 16.40
84260 8-18-20 82% 14.3 17.44
84307 8-19-20 59% 10.3 17.46
84356 8-20-20 66% 11.4 17.27
84403 8-21-20 65% 11.4 17.54

 

[SparkE]

New battery pack : $4300

https://www.gmpartsclub.com/oem-parts/gm-battery-tray-23348215

.
$4300 is a dam good price (IMO). As a comparaison, think about how much an ICE full engine rebuild costs?

A note to anyone who might be interested : I notice that the pack is listed for 2015-16 only, not 2014.

 

[ElDobro]

New battery pack : $4300

https://www.gmpartsclub.com/oem-parts/gm-battery-tray-23348215

.
$4300 is a dam good price (IMO). As a comparaison, think about how much an ICE full engine rebuild costs?

A note to anyone who might be interested : I notice that the pack is listed for 2015-16 only, not 2014.

2014 pack is kaput. The 2015-16 pack has to be adapted to the car.