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: "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. Taking a photo of the diagnostic screen revealed: 4 C increase, 23 C 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. Without preconditioning, the peak, initial charge rate never exceeded 100 kW: With preconditioning, it easily exceeded 100 kWh. Here I'm at 114 kWh AFTER adding 9 miles (~3 kWh) charge to the battery. CONCLUSIONS 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 FOLLOW UP 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
My 2026 bZ is scheduled to be delivered to the dealer either today or tomorrow. Not sure how realistic that is, but we can at least say "soon" and be assured I will have lots of opportunity to monitor the new preconditioning feature with winter in our Northern latitudes. What I'm most curious about is the temperature it targets. When dealing with the usual daily temps (typically in the teens), how much of a warm-up should I expect while driving in the highway? Does it reach the target within 20 minutes? What was the amount of kWh consumed to achieve that?
I’ve not done a study but but my impression is 55 F or colder really put a hurt on performance. Bob Wilson
22F this AM probably 35 or so overnight in the garage. HVAC failure (have 3...big house) spent the day waiting for the promised repairman.
i'm not sure what this has to do with winter driving, but it was 8f here this morning, but at least the car started
