I recently purchased a CPO Spark EV with 44,000 miles. This is my second Spark EV as I leased a 2014 when it first came out. I love the car and it would be my perfect car if it only had a 150 miles range or so. That said, the range is what it is. I understand that battery degradation is an unavoidable consequence of having an EV.
As I understand it the battery capacity of 2015 -2016 Spark EVs is 19 KWh and the EPA estimated range is still 82 miles. If all of the battery capacity were useable (which I know it isn't) that would mean that under EPA conditions 4.3 mi/KWh would be the energy efficiency. If one assumes a useable capacity of 18 KWh then we are talking about 4.6 mi/KWh. Battery degradation and reduced capacity would obviously reduce overall range, but it should reduce efficiency on a mile / KWh basis. Unless there is an increase in driveline inefficiency the "mi/KWh" numbers should remain constant, no?
Over my first 250 miles I am seeing efficiencies in the 3.9 - 4.0 range when I charge and reset, and average battery capacity of 13.23 KWh (70% of new). (driving in "L" which would over represent capacity due to Re-gen). even when I drive at a leisurely pace, 60 mph on the highway, I only see 4.0 mi/KWh. My tires look to be pretty crappy generic unbranded "Road Huggers". I seem to remember on my 2014 Spark EV being able to readily achieve 4.5 - 5.0 mi/KWh efficiencies on the stock Bridgestone Ecopia tires and even when I changed the fronts to Yokohama Avid Ascends, efficiencies barely dropped.
Would simply going with a better or LRR tire improve my efficiencies? Have other owners seen a drop in mi/KWh independent of other changes?