INTRODUCTION
I've long wondered about how much energy is used in preconditioning and the charging time effects. Also cold weather effects on range as I will be driving to Las Vegas in January, winter in our Northern latitudes.
BACKGROUND
The trip energy usage display often shows "how many miles lost to preconditioning" but not the kWh. So when I saw "lost 2 miles" while doing 4 miles/kWh on a mild day, I figured 500 Wh but what is really going on?
EXPERIMENT
I needed to run an errand 350 miles away on a cold, overcast day running 30-35 F (-0.5 to 2.2 C.) Using a SuperCharger automatically starts preconditioning. But switching to a business in the SuperCharger area defeats preconditioning. So this is what happened:
Next week, I need to replicate this errand. Only next time, I will duct-tape, a layer of cardboard insulation below the battery. This should reduce the thermal loss and quantify the effect.
Bob Wilson
I've long wondered about how much energy is used in preconditioning and the charging time effects. Also cold weather effects on range as I will be driving to Las Vegas in January, winter in our Northern latitudes.
BACKGROUND
The trip energy usage display often shows "how many miles lost to preconditioning" but not the kWh. So when I saw "lost 2 miles" while doing 4 miles/kWh on a mild day, I figured 500 Wh but what is really going on?
EXPERIMENT
I needed to run an errand 350 miles away on a cold, overcast day running 30-35 F (-0.5 to 2.2 C.) Using a SuperCharger automatically starts preconditioning. But switching to a business in the SuperCharger area defeats preconditioning. So this is what happened:
- "drive" - the driving time and charging time for each segment at that destination.
- Departure time at 4 AM so cabin, battery, and car were ready to arrive at Florence starting from a preconditioned state.
- "drive" - subsequent drive and charging sessions with and without preconditioning.
- 4 C increase, 23 to 27 C, in coolant temperature - at the charger, it continues to raise the battery temperature by taking some of the charging energy to warm the coolant. You can't escape not warming the battery, energy tax.
- Driving keeps the battery at 25-30 C, warmer than ambient but not enough for preconditioning.
- With preconditioning, it easily exceeded 100 kWh. Here I'm at 114 kWh AFTER adding 9 miles (~3 kWh) charge to the battery.
- Impossible to escape the battery warm-up or preconditioning energy cost as the car will add that energy at the charger.
- Preconditioning from the battery is in the unit kWh range.
- IF you are on the harry edge of not reaching a SuperCharger, change the destination to a nearby business and turn off preconditioning to add a few miles. But charging will take longer.
- Near freezing weather cuts efficiency from normally 4+ mi/kwh to 3 mi/kWh
Next week, I need to replicate this errand. Only next time, I will duct-tape, a layer of cardboard insulation below the battery. This should reduce the thermal loss and quantify the effect.
Bob Wilson
Last edited: