ElDobro
Posts: 91
Joined: Sat Aug 31, 2019 1:05 pm
Location: NJ

Re: Battery degredation

Sat Aug 01, 2020 8:53 am

marcusku wrote:
Sat Aug 01, 2020 8:29 am
Two dealers now have told me that they do not have a way to give me the theoretical capacity but plugging into the car's computer. So if this is true how do they determine of the battery is below the threshold?
There's a document they have to follow and it requires a scan tool.

NORTON
Posts: 1337
Joined: Fri May 01, 2015 5:52 am
Location: KC,MO

Re: Battery degredation

Sun Aug 02, 2020 7:30 am

Recent data points from the car's energy page:

miles - date- - - display #'s - - calc kWh
81697 -6-12-20 -58% -10.2 -17.59
82314 -6-29-20 -81% -14.0 -17.28
81557 -6-9-20 -61% -10.9 -17.87
83298 -7-23-20 -63% -11.1 -17.62
(not sorted correctly...)

Are these numbers going to be that much different from what one would get from TorquePro or the dealer's Scan system?
Used '14 2LT w/ DCFC. +85k miles.
Mostly free charging! Only one LONG visit to the shop....
GM needs Modern Troubleshooting tools for Modern EV's.
3 step Trouble Tree, 1st try car died again, 2nd try / cost $800. 3rd try fixed the problem.

MrDRMorgan
Posts: 1143
Joined: Wed Oct 30, 2013 7:27 am
Location: Manteca in Central California

Re: Battery degredation

Sun Aug 02, 2020 3:00 pm

NORTON wrote:
Sun Aug 02, 2020 7:30 am
Recent data points from the car's energy page:

miles - date- - - display #'s - - calc kWh
81697 -6-12-20 -58% -10.2 -17.59
82314 -6-29-20 -81% -14.0 -17.28
81557 -6-9-20 -61% -10.9 -17.87
83298 -7-23-20 -63% -11.1 -17.62
(not sorted correctly...)

Are these numbers going to be that much different from what one would get from TorquePro or the dealer's Scan system?
Norton - I have a bigger question! How does one drive a 2014 Spark EV for almost 83k miles and still have a calculated battery capacity of 17.62 kWh when the battery capacity in my 2014 Spark EV w/o DCFC and 24k miles on the ODO is already 15.0 kWh ???? What is your secret? :D

NORTON
Posts: 1337
Joined: Fri May 01, 2015 5:52 am
Location: KC,MO

Re: Battery degredation

Wed Aug 05, 2020 10:01 am

MrDRMorgan wrote:
Sun Aug 02, 2020 3:00 pm
.... What is your secret? :D
First, are these numbers going to be much different than if I used the TorquePro app?

Second, the only thing I do which considers battery health is to not leave it at 100% SOC for longer than necessary.
For the most part I charge once a day, and leave it at home overnight at <60%, then charge at work next day.
If it's a hot one, I'll wait until lunch to plug into the Free Public L2 so it is topped up for less than an hour or so.

That's it!! These cars are happiest using Free electrons! :lol:

I definitely don't baby it. I bump the 90 mph limiter once or twice a week and commute in the left lane with my buds at +70-85 mph.
I like to accel semi-hard up to speed then hit the cruise control.
I'm easy on the brakes and regen forces. I use N to coast off the highway.

Weekends are a different story. We just putz around town locally... She's in the car usually... :P
I'm such a cheap azz that if I need to add some electrons I'll add just enough to get to work on Monday morning.
Used '14 2LT w/ DCFC. +85k miles.
Mostly free charging! Only one LONG visit to the shop....
GM needs Modern Troubleshooting tools for Modern EV's.
3 step Trouble Tree, 1st try car died again, 2nd try / cost $800. 3rd try fixed the problem.

TheLondonBroiler
Posts: 256
Joined: Tue Oct 31, 2017 6:25 am

Re: Battery degredation

Wed Aug 05, 2020 2:04 pm

NORTON wrote:
Wed Aug 05, 2020 10:01 am
First, are these numbers going to be much different than if I used the TorquePro app?
From my experience, the Torque Pro capacity figure is pretty well accurate. With batteries, capacity will vary depending on discharge rate, temperature, and probably other factors I don't even know about. I've pulled more energy than the claimed Torque Pro figure, on mild days, with conservative driving. I haven't tried a high speed run to test the opposite, but I'm betting I could get a lower figure.

Speaking of figures, I just checked my Spark and the capacity is down 0.7kwh (13.3 from 14.0), from when I last paid it attention several months ago. It stays stored in the garage, generally kept at 60% SOC (+/-10%).

Image
NORTON wrote:
Wed Aug 05, 2020 10:01 am
Second, the only thing I do which considers battery health is to not leave it at 100% SOC for longer than necessary.
For the most part I charge once a day, and leave it at home overnight at <60%, then charge at work next day.
If it's a hot one, I'll wait until lunch to plug into the Free Public L2 so it is topped up for less than an hour or so.
I think this is a great habit and probably does explain a seemingly better than average battery capacity. Lithium cells that are a nominal 3.7 volts configuration, from all I've seen, don't fair too well in terms of lifespan, when regularly kept at higher than 4.0 volts, especially in hot temps. How does this relate to the Spark? Well in my 2015 @ 67.8% SOC (just happens to be at this SOC right now), the average cell voltage is 3.92 volts.
Image
At 75% SOC and higher, you're above 4.0 volts (going off memory). Those of us who keep the SOC high because we have to drive long distances (in relation to a single charge range), and don't have access to convenient charging during that trip/commute, are probably causing greater wear on the battery, albeit unintentional.

Random thought I just had, since 2014 A123 packs are 112 cells in series instead of 96 in series in the 2015&16 LG packs, and the packs are the same voltage, the average cell voltage should be lower. I do remember scanning LOAF's 2014 almost two years ago, and noticing how low the cell voltages seemed in relation to SOC. The two manufacturers likely used different chemistries, but it still may be beneficial to have a 2014 (with dcfc of course :D ), in this regard.
2015 Spark EV w/ DCFC 48,XXX miles
Purchased 1/20/18 w/ 16,5XX miles
0-40k mile efficiency avg - 5.3 mi/kwh

2019 Bolt EV w/ DCFC 63,XXX miles
Purchased 3/16/19 w/ 87 miles
Lifetime efficiency avg - 4.7 mi/kwh

NORTON
Posts: 1337
Joined: Fri May 01, 2015 5:52 am
Location: KC,MO

Re: Battery degredation

Thu Aug 06, 2020 9:59 am

TheLondonBroiler wrote:
Wed Aug 05, 2020 2:04 pm
From my experience, the Torque Pro capacity figure is pretty well accurate.
How do you know this?
Compared to what?
That's exactly my question.
Compared to the dealer's scanning tool, or the car's energy usage page?
Used '14 2LT w/ DCFC. +85k miles.
Mostly free charging! Only one LONG visit to the shop....
GM needs Modern Troubleshooting tools for Modern EV's.
3 step Trouble Tree, 1st try car died again, 2nd try / cost $800. 3rd try fixed the problem.

TheLondonBroiler
Posts: 256
Joined: Tue Oct 31, 2017 6:25 am

Re: Battery degredation

Thu Aug 06, 2020 10:09 am

NORTON wrote:
Thu Aug 06, 2020 9:59 am
How do you know this?
Compared to what?
That's exactly my question.
Compared to the dealer's scanning tool, or the car's energy usage page?
Compared to the car's Energy Usage Screen. The battery capacity guess is pulling data from the BECM, and therefore should be the same figure the dealer would get.

I just finished a ~120kph/75mph efficiency/range test. The energy usage screen estimated around 13.6kwh available (I ran it to 36% SOC with 9.1kwh used, started with a full charge. Torque Pro readout is 13.3kwh.
2015 Spark EV w/ DCFC 48,XXX miles
Purchased 1/20/18 w/ 16,5XX miles
0-40k mile efficiency avg - 5.3 mi/kwh

2019 Bolt EV w/ DCFC 63,XXX miles
Purchased 3/16/19 w/ 87 miles
Lifetime efficiency avg - 4.7 mi/kwh

MrDRMorgan
Posts: 1143
Joined: Wed Oct 30, 2013 7:27 am
Location: Manteca in Central California

Re: Battery degredation

Thu Aug 06, 2020 2:01 pm

TheLondonBroiler wrote:
Thu Aug 06, 2020 10:09 am
NORTON wrote:
Thu Aug 06, 2020 9:59 am
How do you know this?
Compared to what?
That's exactly my question.
Compared to the dealer's scanning tool, or the car's energy usage page?
Compared to the car's Energy Usage Screen. The battery capacity guess is pulling data from the BECM, and therefore should be the same figure the dealer would get.

I just finished a ~120kph/75mph efficiency/range test. The energy usage screen estimated around 13.6kwh available (I ran it to 36% SOC with 9.1kwh used, started with a full charge. Torque Pro readout is 13.3kwh.
Am I am reading your numbers correctly? You started with a fully charged battery which measured 13.6 kWh being available and, I assume, SOC was 100%. Therefore, you used 9.1 kWh during your rocket trip down the road leaving 36% remaining (you used 64%) in the battery at the end of your ride.

Therefore, 9.1 kWh / 64% = 14.2 kWh calculated battery capacity. This number will drop if your starting SOC was less than 100%.

TheLondonBroiler
Posts: 256
Joined: Tue Oct 31, 2017 6:25 am

Re: Battery degredation

Thu Aug 06, 2020 3:22 pm

MrDRMorgan wrote:
Thu Aug 06, 2020 2:01 pm
Am I reading your numbers correctly?

Therefore, 9.1 kWh / 64% = 14.2 kWh calculated battery capacity. This number will drop if your starting SOC was less than 100%.
Morgan, you are correct. This is what happens when I use the calculator in my head.

I did another run with an average moving speed of 55mph, but was mostly doing 62 on the interstate, and averaged 6.0 miles per kwh (or 202.2 mpge!) I'm presently transferring and compiling footage from those trips, and if weather permits, I'm going to do a city circuit on 35 & 40 mph roads within the i485 loop in Charlotte. I should have a few of my usual horrible videos posted in a few days.
2015 Spark EV w/ DCFC 48,XXX miles
Purchased 1/20/18 w/ 16,5XX miles
0-40k mile efficiency avg - 5.3 mi/kwh

2019 Bolt EV w/ DCFC 63,XXX miles
Purchased 3/16/19 w/ 87 miles
Lifetime efficiency avg - 4.7 mi/kwh

MrDRMorgan
Posts: 1143
Joined: Wed Oct 30, 2013 7:27 am
Location: Manteca in Central California

Re: Battery degredation

Fri Aug 07, 2020 7:02 am

TheLondonBroiler wrote:
Thu Aug 06, 2020 3:22 pm
MrDRMorgan wrote:
Thu Aug 06, 2020 2:01 pm
Am I reading your numbers correctly?

Therefore, 9.1 kWh / 64% = 14.2 kWh calculated battery capacity. This number will drop if your starting SOC was less than 100%.
Morgan, you are correct. This is what happens when I use the calculator in my head.

I did another run with an average moving speed of 55mph, but was mostly doing 62 on the interstate, and averaged 6.0 miles per kwh (or 202.2 mpge!) I'm presently transferring and compiling footage from those trips, and if weather permits, I'm going to do a city circuit on 35 & 40 mph roads within the i485 loop in Charlotte. I should have a few of my usual horrible videos posted in a few days.
..

My First Spark EV was a leased 2015 2LT with DCFC. For three years I used the data from the Energy Information screen to estimate my battery capacity which was 18.8 kWh at 1414 miles and 15.5 kWh at 26,508 miles. In between these dates was a total of 163 measurements. The linear trend line showed a definite decline in battery capacity over time - just as I have seen for my 2014 and 2016 Spark EVs.

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