MrDRMorgan
Posts: 932
Joined: Wed Oct 30, 2013 7:27 am
Location: Manteca, California

Re: Questions and Data tracking

Tue May 21, 2019 8:57 am

Kermit wrote:
Tue May 21, 2019 7:56 am
Data from this month's 100% charge (May.)
Previous Charge to 100% was 108 miles. This charge to 100% and the GOM is at 107 miles.
Previous Charge to 100% kWh was 16.2000. This charge to 100% and the kWh went back down to 16.03333 kWh (odometer is at 13,692). The average was 6.9 mi/kWh this past month and I used 54.3 kWh over 375.6 miles.

Fuel is $2.57/ gallon here now and electricity is $0.074 per kWh so I am getting about 179.2 miles out of what it costs for a gallon of gas right now (after assuming 75% efficiency of the electricity actually into the battery.)

232.5 MPGe 1 Gallon of Gas = 33.7kWh
At 13,605 miles, the battery capacity for my 2016 Spark EV was 16.5 kWh. Today, at 19,031 miles, my battery capacity is 15.5 kWh as measured using TorquePro. But..... in early April 2019 I started limiting my L1 and L2 charging on my 2014 and 2016 Spark EVs to 80-85%. For the last 1000 miles on each car, there has been no change in the measured battery capacity. I will have to collect data for the next 6 months or so to see if this change in charging significantly reduces my battery degradation rate. Prior to starting this test, the battery degradation rate for both cars was about 0.25 kWh per 1000 miles.

scrambler
Posts: 132
Joined: Sat Jan 14, 2017 4:11 pm

Re: Questions and Data tracking

Tue May 21, 2019 9:02 am

The loss of capacity on our 2014 is a straight downward line that shows no sign of slowing down.

Over the last two years, it has been declining 0.15 kWh per 1,000 miles going from 15.8 kWh at 52,000 miles, down to 13.7 kWh at 66,000 miles.

If I assume a nominal usable capacity of 19 kWh that means the battery lost 27.7 %
If I assume a nominal usable capacity of 20 kWh that means the battery lost 31.5 %

Given I do about 7,000 miles a year with that car, I loose about 1.05 kWh per year.
If the nominal usable capacity is 19 kWh I should cross the 65% line at the end of the year at 71k miles
If the nominal usable capacity is 20 kWh I should cross the 65% line August next year at 75k miles

It will be interesting to see how that goes with GM :)

Has anyone ever been at a dealer for a battery degradation official estimate, and if so how much were you charge for it?

MrDRMorgan
Posts: 932
Joined: Wed Oct 30, 2013 7:27 am
Location: Manteca, California

Re: Questions and Data tracking

Tue May 21, 2019 1:38 pm

scrambler wrote:
Tue May 21, 2019 9:02 am
The loss of capacity on our 2014 is a straight downward line that shows no sign of slowing down.

Over the last two years, it has been declining 0.15 kWh per 1,000 miles going from 15.8 kWh at 52,000 miles, down to 13.7 kWh at 66,000 miles.

If I assume a nominal usable capacity of 19 kWh that means the battery lost 27.7 %
If I assume a nominal usable capacity of 20 kWh that means the battery lost 31.5 %

Given I do about 7,000 miles a year with that car, I loose about 1.05 kWh per year.
If the nominal usable capacity is 19 kWh I should cross the 65% line at the end of the year at 71k miles
If the nominal usable capacity is 20 kWh I should cross the 65% line August next year at 75k miles

It will be interesting to see how that goes with GM :)

Has anyone ever been at a dealer for a battery degradation official estimate, and if so how much were you charge for it?
I wonder if dealers even have the proper equipment. Here is a link to the Idaho National Laboratory's battery capacity testing on four 2015 Spark EVs. This is data I believe and it does show battery degradation.
https://avt.inl.gov/vehicle-button/2015-chevrolet-spark

TheLondonBroiler
Posts: 179
Joined: Tue Oct 31, 2017 6:25 am

Re: Questions and Data tracking

Tue May 21, 2019 3:54 pm

MrDRMorgan wrote: I wonder if dealers even have the proper equipment. Here is a link to the Idaho National Laboratory's battery capacity testing on four 2015 Spark EVs. This is data I believe and it does show battery degradation.
https://avt.inl.gov/vehicle-button/2015-chevrolet-spark
Very interesting write up by INL, thank you for sharing! I do see some discrepancies, but they appear minimal. With their efficiency, whoever was driving was ALWAYS VERY COMFORTABLE (It would have been heat to see their climate % of battery usage).

Dealers probably read the bms, just like we do with Torque Pro. I had brief access to alldata a few months back, there is a lengthy write up on HV battery replacement procedures.
2015 Spark EV w/ DCFC 46,XXX miles
Purchased 1/20/18 w/ 16,5XX miles
2019 Bolt EV w/ DCFC 6,XXX miles
Purchased 3/16/19 w/ 87 miles

Kermit
Posts: 37
Joined: Mon Feb 04, 2019 10:47 am

Re: Questions and Data tracking

Mon Jun 17, 2019 10:06 am

Data from this month's 100% charge (June.)
Previous Charge to 100% was 107 miles. This charge to 100% and the GOM is at 96 miles.
Previous Charge to 100% kWh was 16.03333. This charge to 100% and the kWh remained at 16.03333 kWh (odometer is at 14,008). The average was 5.1 mi/kWh this past month over 316.2 miles.
My wife drove the car for a week and it got charged to 100% most days that week and she pulled the average mi/kWh down to ~4.5mi/ kWh. I also rode my bike to work one week so the mileage was less than last month.

Fuel is $2.44/ gallon here now and electricity is $0.074 per kWh so I am getting about 126.1 miles out of what it costs for a gallon of gas right now (after assuming 75% efficiency of the electricity actually into the battery.)

171.87 MPGe (1 Gallon of Gas = 33.7kWh)
2016 Spark EV

SparkE
Posts: 308
Joined: Tue Sep 06, 2016 1:18 am

Re: Questions and Data tracking

Fri Jun 21, 2019 8:59 am

UNLESS YOU NEED THE RANGE on any particular day, I would highly recommend *NOT* charging to 100% nightly. *In general* Li_Ion batteries do not like it when completely charged or discharged (it does vary by exact chemistry of battery and anode/cathode composition). Yes, the car's engineers made it so that the batty is nover 'fully' charged or discharged, however ...

I lost very little capacity in my first SparkEV, as I rarely charged to 100%. (the Guess-O-Meter = GOM is a horrible way to estimate, but that's all I had at the time). I started with 110 miles round town, and over 2 years it dropped to around 104-106. I try to keep the battery between 30-80%, but I'm not a fanatic about it ; I just try to make that the 'norm'. (I also try to not 'fast charge' much past 70%.) If I know I'm going to be driving a long day, I charge up. I really, really try to never drop the range below 10 miles. And I charge to 'full' once every 4-6 weeks to make sure that the batteries are balanced.

Edit: Oh, we also have a gas-mobile, so that if I am ever caught short on a particular day, we just drive gas. Not so easy for those who only have one car.

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