captainowow
Posts: 1
Joined: Sun Feb 10, 2019 9:27 am

2015 Chevy Spark EV battery

Sun Feb 10, 2019 9:35 am

Am new to this forum but believe I've read enough to now think I made a mistake in purchasing a used 2015 Spark. It only has 30k mileage but it look like the battery(s) may be losing life. We purchased the 240v outlet to charge our spark. Since October it was charging at a range of around 65-68 miles, which I found superior but, in the last 2 weeks its only charging 58 miles regularly. I drive to and from work and daily end up with the final mileage left at around 14 miles.

Should we be concerned the battery is no longer showing signs of high charge volume? I say the cost to replace the batteries is around $10k on a couple of webpage. I am recovering from cancer and we have no more savings for such an expense.

Should I shoot myself for buying a used Spark? or is there still hope of longevity for our car?

OB

NORTON
Posts: 1193
Joined: Fri May 01, 2015 5:52 am
Location: KC,MO

Re: 2015 Chevy Spark EV battery

Sun Feb 10, 2019 11:04 am

captainowow wrote: โ†‘
Sun Feb 10, 2019 9:35 am
.... is there still hope of longevity for our car?
Hang in there until spring! I think you'll like the numbers you see then.

My Spark EV is finally displaying in 60 mi range in this terrible midwest weather we have been having lately.
I haven't logged battery capacity numbers from the 'Energy Page' because I don't get it below 50% capacity in my winter commuting.
I plug in at home and at work in the winter months.
I'm approaching 62k mi. and I feel the pack is doing fine.

Keep in mind all Li-Ion batteries have degradation due to usage and life.
When people ask me 'How much?' to replace the pack, I answer 'When do I replace the pack?' At 60 mi. range? At 50 or 40?
Someone on this forum is over 100k miles on his Spark EV.
Used '14 2LT w/ DCFC.
+65k miles. Only one LONG visit to the shop....
GM needs Modern Troubleshooting tools for Modern EV's.

scrambler
Posts: 127
Joined: Sat Jan 14, 2017 4:11 pm

Re: 2015 Chevy Spark EV battery

Sun Feb 10, 2019 2:07 pm

And remember, the range estimate has nothing to do with the battery charge level.
It is just a guess on how many miles you may be able to do on a full charge, based on the last few days of use.

So when it changes significantly, it is almost in every case, because the driving conditions have changed in such a way that you are consuming more electricity. Things like colder weather, use of the heater, higher speed or more agressive driving...

If you want to monitor your battery capacity, search this form and you will find several ways to do that in a reasonably reliable ways.

I bought a 2014 used a few years ago with 52k miles that was showing a usable capacity of about 16kwh. Now at 65k miles, I am down to around 14kwh, and the chart of the capacity overtime is a regularly descending one.
Image
Last edited by scrambler on Sun Feb 10, 2019 3:15 pm, edited 1 time in total.

SparkE
Posts: 303
Joined: Tue Sep 06, 2016 1:18 am

Re: 2015 Chevy Spark EV battery

Sun Feb 10, 2019 2:16 pm

captainowow wrote: โ†‘
Sun Feb 10, 2019 9:35 am
Am new to this forum but believe I've read enough to now think I made a mistake in purchasing a used 2015 Spark. It only has 30k mileage but it look like the battery(s) may be losing life. We purchased the 240v outlet to charge our spark. Since October it was charging at a range of around 65-68 miles, which I found superior but, in the last 2 weeks its only charging 58 miles regularly. I drive to and from work and daily end up with the final mileage left at around 14 miles.

Should we be concerned the battery is no longer showing signs of high charge volume? I say the cost to replace the batteries is around $10k on a couple of webpage. I am recovering from cancer and we have no more savings for such an expense.
The 'range' displayed on the dash screen is humorously call the G-O-M, which stands for "Guess O' Meter" : it is an estimate (GUESS) of your range based on previous data (speed, driving style, rolling resistance {tire inflation}, terrain {UP hills then DOWN hills}, fighting head-on wind, weather {poor mileage in rain}, etc.). The guess is primarily based on the "Miles per Kilo-Watt-hour" figure (m/kWh) that the car calculates has been used - how far you can drive for each kWh of energy pulled from the battery. The biggest thing that a driver can do to increase driving efficiency in all weather is *slow down*. That is because wind resistance goes up with the SQUARE of the speed.

One of the things that will affect your range is *temperature*. It will affect it a LOT. The "store energy in battery" and "take energy out of battery" is a *chemical* reaction, which does not perform as well when it is cold, so the efficiency (m/kWh) goes down.

The other big thing affecting range in cold weather is the heater. In a gas car, the engine produces heat as a by-product, which is generally thrown away, but when it is cold it is piped into the car cabin to heat it, and it costs nothing (doesn't affect mileage). An electric car on the other hand has to run the heater using electricity (just like a small home electric heater or a toaster) - which thus is electricity that *isn't* being used to move the car forward, it is used all the same but is used instead to heat - so the m/kWh pulled from the battery goes down - a LOT. (Winter mileage can tank by 33% or even more if it is *really* cold. It will still have a noticeable effect, even if it is 'only' 45 degrees in the morning.)

Short story (maybe a bit too late for that ... ;) ) : your range estimate should go back up when it warms up.

If your 'regular' speed is 70 mph, then slowing down to 55 mpg will let you drive further (15%? 25%?)

You can "remote start" (also called "preconditioning") the car. Read the manual to see how to use the key fob to start this. If you 'precondition' the car, it will pull the energy needed for this from the wall instead of pulling it out of the battery - so do this when the car is plugged in, and do it about 10-15 minutes before you leave the house. Preconditioning will turn on the battery heater (warming the battery for greater efficiency while driving) AND it will use the climate settings that were in place when the car was last turned on. So, when you park the car in the evening, set the heater to (say) 72 degrees F, and the fan to 2 or 3. When you precondition the car the next morning, the car will be toasty warm inside when you get in, and the battery will be warmer and more efficient.

Some useful info/tactics for winter :
- use "preconditioning" to warm battery and the car inside when plugged in (remember to set heater controls just before turning the car off)
- use the "seat warmer" while driving, instead of the car's (air) heater - MUCH more efficient. While driving, turn air heater OFF (unless you need defrost)
- find (and bring with you) a lap blanket - a smallish blanket the you put on your lap that covers your lap/upper legs while driving (NOT your feet which might interfere with braking or accel). That will keep you warmer during the drive, especially if you use the seat warmer. Don't leave the blanket in the cold car if you can help it : bring it inside the home at night, and inside to work during the day (so the blanket is warm, or at least NOT cold) when you put in on your lap
- since the heater isn't going to be on, drive with (warmed) gloves and a coat instead of using the heater all the time

All that being said, if you generally only drive the car for 2-6 miles before you park it again, all of the "warm the battery" and "use a blanket" techniques aren't going to make a big difference in your everyday life (unless you regularly drive close to the range limit fairly often, when it would be useful to get an extra 4 or 8 miles of range). If the car is just an 'around the town' car, simply put your mind at ease and tell yourself that the estimated range will go back up when it warms up.

SparkE
Posts: 303
Joined: Tue Sep 06, 2016 1:18 am

Re: 2015 Chevy Spark EV battery

Sun Feb 10, 2019 2:36 pm

For anyone that cares, the drag force can be modeled by this equation :

๐น๐ท=12๐œŒ๐ถ๐ท๐ด๐‘ฃ2

where

๐น๐ท is the drag force, which is by definition the force component in the direction of the flow velocity
๐œŒ is the mass density of the fluid (air in our case: ๐œŒโ‰ˆ1.1839 Kg/m3 at 1 atm and 25 ยฐC)
๐‘ฃ is the velocity relative to the air
๐ด is the reference area, the cross sectional area of the front of the car
๐ถ๐ท is the drag coefficient - a dimensionless coefficient related to the object's geometry and taking into account both skin friction and form drag; in the case of the Chevy Spark, ๐ถ๐ท= 0.32

The thing that a DRIVER can influence is velocity (speed) - everything else is either fixed (Cd, A) or the driver cannot control (air density). Luckily for US, the v is the variable that has the most effect, as it is squared.


So, if the air resistance at 35 mph were 4 boo-bops (yeah, making it up) then the air resistance at 70 mph would be 16 boo-bops.

MrDRMorgan
Posts: 914
Joined: Wed Oct 30, 2013 7:27 am
Location: Manteca, California

Re: 2015 Chevy Spark EV battery

Wed Mar 13, 2019 12:48 pm

scrambler wrote: โ†‘
Sun Feb 10, 2019 2:07 pm
And remember, the range estimate has nothing to do with the battery charge level.
It is just a guess on how many miles you may be able to do on a full charge, based on the last few days of use.

So when it changes significantly, it is almost in every case, because the driving conditions have changed in such a way that you are consuming more electricity. Things like colder weather, use of the heater, higher speed or more agressive driving...

If you want to monitor your battery capacity, search this form and you will find several ways to do that in a reasonably reliable ways.

I bought a 2014 used a few years ago with 52k miles that was showing a usable capacity of about 16kwh. Now at 65k miles, I am down to around 14kwh, and the chart of the capacity overtime is a regularly descending one.
Image
This graph is interesting. You are showing a loss of approximately 1.0 kWh per year from 50k miles o 62k miles. For the last 7 months I have been using TorquePro to measure the battery capacity in my 2014 and 2016 Spark EVs. Both cars currently have about 17k miles on the ODO. Low and behold, the battery capacity in each car has decreased 0.9 kWh over the last 7 months. The battery capacity in the 2014 is currently 16.3 kWh and the battery capacity in the 2016 is 15.7 kWh. If this continues, Chevrolet may have to replace the battery in both cars.

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