New AAA Study Shows Electric Vehicle Range Is Cut Dramatically In Winter - How Did Tesla Do?

A new study by AAA provides some firm data to back up what most electric vehicle owners know, and few electric vehicle manufacturers mention in their advertisements. EV range is dramatically reduced in cold temperatures. How much is it reduced? On average about 41% according to AAA who compared the driving range of five battery-electric vehicles (BEVs) at 25F to the driving range at 75F.

The study includes affordable, premium, and luxury BEVs. Among the vehicles studies, the BMW i3 had the most reduction as a percentage of its range and the Nissan Leaf, the least reduction. The Tesla Model S, eGolf, and Bolt were in the middle area of range reduction. Every EV studies had a significant reduction.

The AAA study looked at the range reduction in two ways. First, with no HVAC usage. We find it unrealistic that a vehicle owner would not use any of the car's heating systems, including seat heating or steering wheel heating in 25F weather, but perhaps with preconditioning, this is a possibility. In any case, the average reduction in range with zero HVAC usage at 25F compared to 75F was a reduction of about 12%.

When using the heating systems the drop is much more dramatic. The average for the five vehicles was 41%. That average takes into account a few different test cycles, which is why the top of page chart shows multiple comparisons for Model S 75D. The Model S lost just under 40% of its available range when its HVAC system was used in colder weather. If you have a Tesla, that is not really a huge problem if you are starting out with a full battery charge at home, particularly if your cabin and car are preconditioned (which uses grid energy to warm the car and its components before you set out). However, if you have an EV with a range in the neighborhood of say, 150 miles, that is now cut to as little as 80 or so.

As the second chart from AAA shows, warm weather, say 95F, also detracts from range.

AAA is far from the first group to look at EV range in winter. However, it is one of the most respected. Other less formal studies have shown that EVs have a shorter range than advertised in winter and that they also can take up to twice as long to charge. Torque News found this to be particularly true recently when our test EV would only add back about 1.7 miles per hour on a 115 Volt charger. When we set the vehicle to precondition overnight we ended up with a net loss of displayed available range.

You can view the AAA study in its entirety here.