neomaxcom
Posts: 15
Joined: Fri Feb 09, 2018 12:37 pm

Re: Battery degredation

Sun May 19, 2019 1:43 pm

I was feeling pretty good about the degradation on my early (Feb 2013 first registration by GM in Michigan) 2014 Spark EV (serial # ends in 000067) last summer. The division method of estimating capacity was showing 15.2 kw capacity as late as last October. I had just turned 20000 miles - I bought in Feb 2018 with 10,000 mi on the clock - when I bought replacement front tires and expected a drop in range from the 80-90 GOM estimate. I even got some 95 mile GOM readings last fall.

Anyway, I was somewhat pleased this last March when we had a stretch of nice weather (Atlanta Ga area) and the GOM returned a low-80s guestimate and mentally I figured that the drop from the 90 mile GOM was due to the tire change.

Last week I had a route that took me over 72 miles with 9 miles left on the GOM and decided to figure battery capacity with a good trip to estimate it. I was a bit taken aback by the 14.4 estimate (13.3 / .92%). Of course I'm down to about 21 months of warranty coverage left but I'm far from the 100,000 mile limit

In reading this topic, I saw that the 2014 Spark EV had a 22kw A123 battery and the 2014's warranty calls for warranty coverage at 65%. That would suggest that warranty replacement could occur when the A123 battery degraded to 14.3 KW within eight years and 100,000 miles.

One thing that has bothered me in all this is that none of the discussions of degradation has ever set an actual capacity in KW at which below that figure invocation of the warranty is certain. Is this because GM hasn't replaced any drive battery for degradation?

It is obvious that some Spark EV's have gone out of warranty on the basis of mileage. What was the battery capacity of those units?

Another question deals with answering 'what is the capacity of a battery in service' - how do you best measure it as obviously I've not been sooo concerned about this that I've not done the OBDII thing. Would a dealership's 'estimate' vary from this 'figure' presumably because of a different measuring routine.

As the Spark EV heads toward its eight year warranty period, it is in the interest of all owners to know how this game is going to be played. As the owner of one of the first to run out of time, I have to also wonder if having my Spark EV in Georgia (not CA) and it having low miles (I estimate under 50,000 at the time the battery warranty expires) will have what impact.

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

Re: Battery degredation

Sun May 19, 2019 2:13 pm

neomaxcom wrote:
Sun May 19, 2019 1:43 pm

In reading this topic, I saw that the 2014 Spark EV had a 22kw A123 battery and the 2014's warranty calls for warranty coverage at 65%. That would suggest that warranty replacement could occur when the A123 battery degraded to 14.3 KW within eight years and 100,000 miles.
First the 2014 Spark total original battery capacity is supposed to be 21kWh not 22 kWh

But the thing to keep in mind is that when you evaluate your current capacity, you are getting the current USABLE capacity, and not the current full capacity.

The nominal USABLE capacity is not the full 21kWh, because the Spark never fully charges or discharges the battery to protect it.
Unfortunately, there are no information on what is the nominal USABLE battery capacity, but it is supposed to be somewhere between 18.5 kWh to 19.5kWh.

This means the threshold for 35% degradation would be around 12 kWh to 12.675 kWh and not 14.3 kWh as you mention above.

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

Re: Battery degredation

Sun May 19, 2019 2:54 pm

scrambler wrote:
Sun May 19, 2019 2:13 pm
neomaxcom wrote:
Sun May 19, 2019 1:43 pm

In reading this topic, I saw that the 2014 Spark EV had a 22kw A123 battery and the 2014's warranty calls for warranty coverage at 65%. That would suggest that warranty replacement could occur when the A123 battery degraded to 14.3 KW within eight years and 100,000 miles.
First the 2014 Spark total original battery capacity is supposed to be 21kWh not 22 kWh

But the thing to keep in mind is that when you evaluate your current capacity, you are getting the current USABLE capacity, and not the current full capacity.

The nominal USABLE capacity is not the full 21kWh, because the Spark never fully charges or discharges the battery to protect it.
Unfortunately, there are no information on what is the nominal USABLE battery capacity, but it is supposed to be somewhere between 18.5 kWh to 19.5kWh.

This means the threshold for 35% degradation would be around 12 kWh to 12.675 kWh and not 14.3 kWh as you mention above.
I purchased a 2014 Spark EV 2LT w/o DCFC which had 1500 miles on the ODO. At 2000 miles, and using the data from the energy information screen, I calculated my battery capacity at 20.01 kWh. Now, at 18435 miles, my TorquePro measured battery capacity is 16.2 kWh. If I assume the "calculated" numbers are reasonably accurate, then I lose 1 kWh in battery capacity every 4300 miles. If I also assume my starting battery capacity value of 20.01 kWh is accurate, a 35% loss would amount to 7 kWh and my warranty point would be at 13.0 kWh or lower. My last TorquePro measurement was 16.2 kWh. If the degradation continues at the current rate, I have to lose 3.2 kwh (13,760 miles) before I can open a warranty claim. The car was first sold in June 2014 so I have until June 2022 before I run out of the time portion of the warranty - just 3 years from next month. It will be close. I could end up with a car having about 32k miles on the ODO and 13 kWhs of battery capacity. At 5 mi / kWh, I will have a maximum range of 65 miles. I am currently achieving 95 miles at 100% SoC (5.86 mi/kWh).

I am now limiting my charging to 80-85% SoC to see if that has any effect. Initial results look good but I need to collect many more months of data to see if the battery continues to degrade at the rate I have seen so far.

My 2016 Spark EV 2LT with DCFC is giving me similar results.

neomaxcom
Posts: 15
Joined: Fri Feb 09, 2018 12:37 pm

Re: Battery degredation

Sun May 19, 2019 6:06 pm

scrambler wrote:
Sun May 19, 2019 2:13 pm
neomaxcom wrote:
Sun May 19, 2019 1:43 pm

In reading this topic, I saw that the 2014 Spark EV had a 22kw A123 battery and the 2014's warranty calls for warranty coverage at 65%. That would suggest that warranty replacement could occur when the A123 battery degraded to 14.3 KW within eight years and 100,000 miles.
First the 2014 Spark total original battery capacity is supposed to be 21kWh not 22 kWh

But the thing to keep in mind is that when you evaluate your current capacity, you are getting the current USABLE capacity, and not the current full capacity.

The nominal USABLE capacity is not the full 21kWh, because the Spark never fully charges or discharges the battery to protect it.
Unfortunately, there are no information on what is the nominal USABLE battery capacity, but it is supposed to be somewhere between 18.5 kWh to 19.5kWh.

This means the threshold for 35% degradation would be around 12 kWh to 12.675 kWh and not 14.3 kWh as you mention above.
Thanks for the correction on the full capacity. It like a lot of things regarding this point in EVs evolution, are based on inadvertent errors and it is always good to clarify the few concrete facts.

But as you point out, the best anyone can muster is KWh range. This is not a criticism of you; rather it is recognition that we're just now beginning to ask the questions.

I also know that as consumers we're starved for information while we also know that GM is, at this moment, collecting information on our cars as a class and knows precisely how the degradation is progressing both in general and in regard to each car. Still, because we don't even know the starting KWh capacity, we're just totally in the dark.

I will say that probably the most critical aspect of this is how to keep this rolling stock (EVs like the Spark) in operation. One way would be to repair or replace batteries when the degradation becomes oppressive. One way to make degradation a minimal inconvenience is to broadly expand the availability of EVSE's. If charging were available at most public parking areas - 1-4 EVSE's available at most places required to have public toilets, the value of a good running but battery-limited EV would expand dramatically. (Remember the time to a full state of charge decreases over time, even for EVs with 3.3 kw L2 maximum charging.)

It is also important, I think, for future Li-on based EVs, that the first generation of the product not be known for junking eight year-old cars with 50,000 miles on them.

fizzit
Posts: 10
Joined: Sun Nov 18, 2018 10:50 pm

Re: Battery degredation

Sun May 19, 2019 6:14 pm

Here's the front page and relevant sections of the my warranty.
https://imgur.com/a/31gcs6x

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

Re: Battery degredation

Sun May 19, 2019 6:26 pm

fizzit wrote:
Sun May 19, 2019 6:14 pm
Here's the front page and relevant sections of the my warranty.
https://imgur.com/a/31gcs6x
Looks like I owe you a beer. Much appreciated.
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

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

Re: Battery degredation

Mon May 20, 2019 8:09 am

The one thing I have really appreciated on this forum is the availability of help and constructive comments that many Spark EV drivers have contributed to our individual EV learning curves. I am in my 5th year of driving a Spark EV and I still have so much to learn.

Please keep up the good work and thanks to all!

The Spark EV is one FANTASTIC LITTLE ROAD ROCKET!!

TheDisco
Posts: 2
Joined: Tue May 28, 2019 7:22 am

Re: Battery degredation

Thu May 30, 2019 8:52 pm

Just bought a 2015, so I have another data point on battery degradation. I have 27k miles and 14.8 kWh battery capacity based on torque pro.

I'm definitely a little disappointed with that figure.

NORTON
Posts: 1210
Joined: Fri May 01, 2015 5:52 am
Location: KC,MO

Re: Battery degredation

Fri May 31, 2019 6:50 am

TheDisco wrote:
Thu May 30, 2019 8:52 pm
...I'm definitely a little disappointed with that figure.
Just for reference, how does this compare to 'On Screen' Leaf page data for battery capacity?
Used '14 2LT w/ DCFC.
+67 K miles. Mostly free electrons! Only one LONG visit to the shop....
GM needs Modern Troubleshooting tools for Modern EV's.

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

Re: Battery degredation

Fri May 31, 2019 7:44 am

TheDisco wrote:
Thu May 30, 2019 8:52 pm
Just bought a 2015, so I have another data point on battery degradation. I have 27k miles and 14.8 kWh battery capacity based on torque pro.

I'm definitely a little disappointed with that figure.
There are many of us Spark EV drivers who are experiencing HV battery degradation, myself included. But, I have not yet seen any postings about a Spark EV driver having to replace his HV battery due to the battery capacity dropping below the warranty limit. Maybe it is still too soon. A friend of mine, who had a leased 2015 Spark EV, also had 14.8 kWh left when he turned in the car with just over 30k miles. My 2016 Spark EV currently has a battery capacity of 15.5 kWh with just under 20k miles.

I am currently limiting my charging to 80 - 90% of a full charge. It is still too soon to tell, but my preliminary data shows my degradation rate has stopped dropping on both my 2014 Spark EV and 2016 Spark EV. I need to test this for many more months to see if it continues or not. Even with 15.5 kWh, my calculated full-charge range (GOM/(SOC*100)) is still near 100 miles.

Each of us will have to decide at what point the battery's degradation reaches a point where the car can no longer meet our driving needs. Each week I have a 130 mile round trip over two long grades and one up hill climb and I have to charge at the half-way point going each direction. This works great so far but the cold winter months and use of the heater makes this a real "E-TICKET" ride.

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