My Spark full charge estimated range just dropped 10%

[Sparki]

I am very happy with the Spark over the last two months and 1,100 miles. Originally, the display consistently showed 85 to 89 miles after a full charge. Starting a few days ago that went to 77 miles and has stuck there over the last three charging cycles. We have never taken the battery below 40% and are charging the slow way through the 115 plug - fine for us as we don't need fast charge times. Is this change in range due to our driving habits and the fact that the computer has determined that this is in fact a more realistic range (my wife loves to take on BMW's at the stoplights while I make a game out of maximizing efficiency)..
Ideas welcome? I don't think it is a sign of premature battery degradation - hope not. Yesterday I computed my theoretical range based on kwh used for a given number of miles and it came out to 87, yet the display maintained that on average I would only get mid 70's??

 

[Electricbowtie]

Welcome to the cold weather. I have had my Volt 18 months now and when it gets colder regardless of running my heater, my range drops from 45 to 35 miles per charge, so I fully expect that with our Spark EV as well. Just plan for shorter ranges and top off when you can.

 

[iletric]

Also, if you're taking on BMWs your GOM may be reprogramming itself as the car remembers previous power usage and adjusts expected range accordingly.

The car is still very new so there will be surprises around the corner. Cold nights definitely are one of those even though TMS does, or is supposed to, kick-in during charging to keep the battery at normal temp. Generally though, you charge up much less juice at 50F and lower than at 75F.

 

[SenorChispa]

I've only had my car 3 days and noticed the same thing and then some. After a full overnight charge, my range is only 73 miles. It has been in the 50's F during the day and 30's at night. Is that considered cold weather? If so I'm in trouble come January when it's in the 30's at noon and the teens at night.

 

[iletric]

Yes, 30s is considered cold for charging the battery - even though Spark has TMS and ambient temp SHOULD NOT be an issue. TMS is supposed to maintain optimal temp during charging. I don't know what the threshold is for it to kick in. I'm sure there are many on this forum who do, and will post.

Makes no difference though because we can do nothing about it other than garage the car.

Generally, you cram less electrons in winter. The optimal temp for charging (i.e. getting the most charge/range) into traction battery is 70-80F.

 

[SenorChispa]

Last night I got only 69 miles at full charge. That's almost 18% below the advertised range. So it has been steadily dropping over the past 3 nights, from 78 the first night to 74 the next, and now 69. Temperature at night has been consistently in the 30s so I think there must be something else going on.

I have been driving pretty aggressively (can't resist). If the range estimator bases it's guess on a rolling average of recently recorded driving history, that would explain the drop. Anyone know if this is the case?

 

[TonyWilliams]

... If the range estimator bases it's guess on a rolling average of recently recorded driving history, that would explain the drop. Anyone know if this is the case?

This is the industry wide normal operation. Only Tesla offers "rated range", where you don't need a fuel gauge. If you charge up to 265 miles, it's full. If the battery becomes degraded, it will only charge to a lower value.

 

[markcmann]

?..I have been driving pretty aggressively (can't resist). If the range estimator bases it's guess on a rolling average of recently recorded driving history, that would explain the drop. Anyone know if this is the case?

If you have been driving "pretty aggressively" this is exactly why the "Guess-O-Meter" has been progressively been dropping your expected range. I've put over 5500 miles on my Spark EV and have seen a range of as low as 78 and as high of 92 and this has been due to a direct correlation to my driving habits. You would see an increase in your expected range by driving a couple of days by driving with a lighter foot.

 

[SenorChispa]

Makes perfect sense. I'll give that a try this week. I wonder what time window it uses for its rolling average., and if it is possible to reset it the way you do a trip odometer?

 

[markcmann]

Makes perfect sense. I'll give that a try this week. I wonder what time window it uses for its rolling average., and if it is possible to reset it the way you do a trip odometer?

It seems to reset (or appears to) between full charging cycles.

 

[gatedad]

Mark:

A better way to gauge the capacity is to use the amount if energy your dashboard shows available every morning when you get in and the see how your typical commute is affected. I drive a Mitsubishi I-MiEV, and my commute is 16.2 miles each way. I know exaclty when I "lose" my first "bar"(I call them energy bars, we have 16 of them on our display). In the summer I get just about 5.4 miles before I lose my first bar. In the winter, however(such as today when we are having a real cold snap here in Philly), I lost my first bar at 4.4 miles. The battery seems to improve as the car is driven in the cold(I guess it heats up internally) and I don't lose nearly as much after about 10 minutes. {Using the heater, though, that's another story altogether...}. I'd suggest seeing if you use the same amount of energy while driving the same route in the same manner. if you get comparable efficiency, then you are really only dealing with the computer estimations being affected by the previous driving you have done. Good luck with your Spark EV! I am jealous.
Lou

 

[SenorChispa]

Having experimented now for while, I can report that the varying range estimation is almost entirely due to driving habits. Temperature doesn't seem to have that much effect, except for the fact that I use the heater more when it's cold. Drive nice for a few days, range goes up each day. Drive fast, range goes down, down, down. The estimator seems to calculate a rolling average over several days (5?).

 

[emissionfree]

I've been experimenting with this for a while now. I think the range estimation history tracking is related closer to distance traveled rather than calendar time. It seems to remember ~100 miles of driving history. Depending on how far your drive, it could take a couple days or even a week to relearn any new driving habits, weather changes, or even vehicle loading (hauling my bicycle).

 

[SenorChispa]

That makes sense. With my commute 100 miles is about 4 days.

Now that I've had the car longer, and we've had a steady run of cold temperature (40s daytime, 20s at night) for a couple of weeks, I do believe that cold has a larger effect than I first thought. The battery pack warmer minimizes the impact, but I still am not able to get quite the range I did in Fall when temps were higher, even when accounting for the increased heater usage. Driving habits and heater usage are certainly the biggest factors, but plain old cold weather does have some impact.