Reduced power from batteries.

[drsurd]

My 2014 L2 w DFCF Spark EV ( 64,000 miles) was getting 5.1 m/kwh til recently. On a trip two weeks ago I got 5.6 mi/kWh on a 150 mile round trip. My Battery has about 15.5 kWh capacity.

I still have the 15.5 kWh capacity but all of a sudden my range is down to about 64 miles while babying it ( no ac, no chamge in temperature, its been around 80 degrees, no change in driving behavior , terrain or weather, tires, or tire inflation. No change in charging. lev II at home.

So the batteries while having the same energy capacity (15.5 kWh) are not producing the same power efficiency.

Any ideas on what can be causing this loss in power efficiency of the batteries?

EE ( battery capacity) + range WAS 5.1 ( 15.5) = 79 mile range.
three days later 4.1 ( 15.5 = 63 mile range

I did not drive below 10 % SOC. GOM showing about 10 miles left on both of these trips.

Something is saping my range. could it be 12 V battery? Brakes are ok and no caliper stuck. thanks for any suggestions.

 

[NORTON]

My 2014 L2 w DFCF Spark EV ( 64,000 miles) was getting 5.1 m/kwh til recently. ....

Something is saping my range. could it be 12 V battery? Brakes are ok and no caliper stuck. thanks for any suggestions.

Tire pressure?
Head winds? (It is possible to get strong headwinds in both directions on a daily commute. But not common...)
Check the Wheel Alignment just to be sure.
(I just spent $23 to check the alignment on my Bolt because I am unhappy with it's efficiency, how about 3.3 mi/kWh ? :? But I have cheapo non-LRR tires on the front... And +80% highway speeds. )
Do you measure your brakes with an IR temp reader? If so use that on the tire tread to see if there are hot areas.
Has your charging routine remained the same? As in, charging over night with similar overnight temps?
What is your energy usage showing for 'Battery Conditioning' after using up the pack?
You said 'No AC usage' so that should display 0%.

You have a weird issue.... Good luck !

 

[Oceanbreeze]

I've seen some of that type of behavior on mine also. I haven't tracked this in terms of the GOM range estimate but specifically only to the drive cycle efficiency shown at the end of every trip. The same exact in-town route on different days with identical mild weather (mid 60s-mid 70s), with no other loads, it often gives 6.7 mi/kWh, but at random times it will give me 5.6, or 8.6, or 9.2 and a few times over 10 mi/kWh (I have pics of some of those runs if anyone wants proof)

The GOM for sure is an estimate based on previous driving patterns but I haven't found how far back the algorithm looks to determine that range estimate. In contrast I've assumed that the drive cycle stats must be very accurate, as it would be fairly reliable to measure the precise amount of energy drawn for a given distance. But with such wild variation, I am beginning to wonder about the precision of those drive cycle calculations. :?

I could only think of some sort of battery conditioning cycle that might be running on some of those drive cycles, but not others. But I haven't seen any document or post that substantiates this.

It looks like you've looked into all the sensible energy draining possibilities.

The only workaround I'd offer is to check the battery energy remaining using a bluetooth OBDII scanner. But I admit, even if you see say 8 kWh remaining, but the GOM gives you a range of say 30 miles you'd probably not want to chance it if you don't have a charging point along the way.

 

[Oceanbreeze]

(I just spent $23 to check the alignment on my Bolt because I am unhappy with it's efficiency, how about 3.3 mi/kWh ? :? But I have cheapo non-LRR tires on the front... And +80% highway speeds. )

That's disappointing, I was hoping the Bolt would be a little more efficient than that, even on hwy usage. Every friend here with a full range EV (Niro, Tesla, ID4) and stock tires gets really low mileage compared to the Spark EV.

 

[NORTON]

That's disappointing, I was hoping the Bolt would be a little more efficient than that, even on hwy usage. Every friend here with a full range EV (Niro, Tesla, ID4) and stock tires gets really low mileage compared to the Spark EV.

But all 'hwy usage' is not the same. Each owner has different usage.
For instance, this time of year and in the winter, almost every return commute has a Precondition cycle to cool the car before getting into it.
That is factored into the mi/kWh displayed.
For me, hwy usage is 65-80 mph keeping pace with the traffic. And it's hotter than HayL and AC is used.
Next set of tires will definitely be LRR, even though on paper that may not 'pay back'.
I just want to see how much better they can be than the cheap'o tires I have on the front currently.

 

[drsurd]

Thanks for the responses.
Tire pressure the same. Driving and charging habits and routes the same. Wind not an issue. This has now gone on
for three weeks. Enough of a sample size to know that energy efficiency has now dropped over 25 % suddenly.

Getting the 12 V battery checked tomorrow.

Or Might be one bad cell in the large battery effecting the overall energy efficiency?

 

[Porsche]

I suspect you really don't have a problem at all. With the information you have given, everything is probably fine. The range displayed after a full charge is dependent on recent driving and is highly variable. And in practice, no two trips are ever really the same. Here's a possible explanation, but just one possible conjecture. You had a sizable trip at 5.6mi/kWh, but a few weeks ago. So, maybe some short trips in between had lower efficiencies. Then, two weeks later, the 5.6mi/kWh trip falls off the back end of the algorithm, and boom, the next full charge shows a lower average. You never said that you consistently see 4.1mi/kWh, you only calculated it, right? Do you actually write down the miles per kWh and odometer change every single time you drive the car and calculate a weighted average, for weeks, months? Or, similarly, you can look at the kWh since last charge display and the total odometer change since last charge. But all of this is really only meaningful over many charges before you'd conclude there's a problem.

Stuff like this happens all the time. Say we have a cold spell. It's been 55F for a few days and I had the heat on. Oh no, after a full charge, I only have a 52 mile range. Of course, my range hasn't changed at all. Now, it's 70 degrees and sunny. I drive for 10 miles. My range changes from 52 miles to 48 miles. I drive another 5 miles. My range stays at 48 miles. I drive another 5 miles. My range goes up to 50 miles. Eventually, things average out.

Here's a little trick I use, especially if the projected range after a full charge seems low. After a full charge, at the beginning of your trip, take the displayed range and add it to the miles on the odometer. Just keep track of the lowest two digits. Then keep track of the sum as you drive. By doing so, You're getting actual miles vs projected miles. You'll know far more accurately what your range will end up being. Here's an example:
Guessometer: 69 miles, odometer: 46,375 miles. sum (truncated to two least significant digits): 69+75 = 164 = 64. Keep that number in your head (or write it down). If you drive 10 miles, but the range only drops by 8, you've added 2 miles to your original 69 mile projection. At any time, you can just add the two again, and if it's more or less (than 64 in this case), that's how much your range went up or down by. Of course, like the stock market, past performance is not a guarantee of future results