Join Date: Jan 2020
Location: Colorado Springs
Cold Weather Effect on Efficiency/Range
During a recent cold snap with temperatures between 5°F and 20°F I was surprised to see the I-Pace consumed 73 kWh/100 miles as reported by WattCat. My range plummeted to 116 miles – a drop of 50%! Wanting to determine the greatest effect on energy consumption/range, I ran a series of 4 tests to determine the overall impact cold weather and climate control has on I-Pace efficiency/range.
I drove a 37 mile country route in 30°F weather at the same time on 4 consecutive nights with no preconditioning. Average speed was 50 MPH +/- 2. Traffic lights were minimal with few vehicles on the road.
Test 1 was without climate control and the car did well using 34.54 kWh/100M (range 245 miles). This was quite unexpected as I believed that a cold battery would lose efficiency. Perhaps the long drive and the I-Pace battery management system helped to keep efficiency near normal. Test 2 was with climate set to 72° but not in Auto and AC turned off. The car managed 46.1 kWh/100M (range 184 miles) - a 33% increase in energy consumption and corresponding loss of range! Test 3 was with climate in Auto and AC on. The results were nearly identical to Test 2 – 45.83 kWh/100M (range 185M). Lastly, Test 4 was with driver seat heater on and climate off. Result was 41.13 kWh/100M (range 206M) - a difference of 19% but keeping the windows clear was a huge problem.
At just below freezing, I managed near normal range/efficiency without climate control. The advice to use seat heaters to save energy is accurate but it's difficult to keep windshield and windows from icing. Using seat heaters uses 24% less energy than using climate control. There has been a lot of discussion about using the climate control in Auto (AC on) or turning the AC off. I saw only a 1% difference between the two methods so use whatever you like. It's probably better to run the AC to keep seals from drying out and then leaking refrigerant.
The other issue is how the I-Pace/InControl reports energy consumption versus WattCat numbers. Test 1 without climate showed WattCat and the I-Pace reported consumption as identical (less than 1% difference) but once climate control is used, the I-Pace underestimated consumption by 18% and underestimated by 11% when using seat heaters. It's clear that the car cannot fully account for energy consumed by the climate control system. It's also evident that short trips have a huge impact on energy consumed in cold weather.
For those planning a long drive in cold weather I recommend you keep a close eye on the miles traveled divided by the SoC drop. Thanks and sorry for the long post.