Featured EV and winter tests posted

It's not just freezing temperatures, but it's typically combined with ice & snow & snow tires Dynamics

 

Looks like they are comparing WLTP to road tests. WLTP is better than NEDC, but still optimistic. For that Model 3, it is 20% better than its EPA rating. Most of those cars will see a loss with summer testing.

 

I go from a high in the best weather of about 6 miles per kWh, to about 4 in the worst weather around here.
Bolt has electrically heated cabin coolant, which sucks up the juice, but the heated seats and steering wheel help minimize it.
An electric windshield would be a help

 

I wonder what the price difference is between Tesla and polestar similarly equipped to get the same winter range and much better summer range for the Tesla

 

The models tested aren't a like comparison. The Polestar 3 is a SUV in the Model Y's class. The Polestar 3's WLTP rating is very close to its EPA; 348 to 350 miles. They must be under selling it from the actual WLTP results. The Model Y is 337 miles.

The range of the Model 3 the article tested on the WLTP is 436 and 363 on the EPA. It went 330 miles on the winter test, or a 9% reduction from EPA. The Polestar 2's EPA range is just 254.

The winter test more shows how poorly the WLTP can represent what an owner can achieve. I suspect it doesn't have a cold or hot cycle like the EPA does. it also shows which manufacturers acknowledge the WLTP's failings in their official published ranges.

The Polestars are $30k+ more than the Teslas in the US. They aren't efficient BEVs, and have bigger batteries.

 

Temperature is a problem. But preconditioning with a scheduled departure time works great:


I've been seeing an estimated range on road trips of about 200-210 miles. Let the grid heat the battery and cabin.

My 2017 BMW i3-REx sees similar loss of EV range but a warm day, and back to normal.

ADDENDUM:

This winter I've observed very high power per mile rates in the first 2-3 miles. Typically this looks like:

• 0-2 mi - about 350 Wh/mi
• 2-5 mi - about 300 Wh/mi
• +5 mi - about 250 Wh/mi

initially, I thought it was the inertial load from starting from park but it also shares similar characteristics with warming something up. Tires are the first thought as they rise from ambient to operational temperatures during the initial 5-10 miles.

The data suggests an early loss is about 1 kWh and then the car parts are at operational temperature. Subsequent charging stops do not show the cold soak, early kWh loss.

• ~213 kWh - inertial energy to accelerate 4000 lbs car and driver to 65 mph
• ~485 kWh - heat water from 32 F to 50 F substituted for tires, 23 lbs each, 92 lbs
• ??? kWh - heating motor and drive gears

As the air density increases from lower temperatures, the energy to move through it increases in a linear fashion. So the linear efficiency decrease relative to temperature seen in my Tesla metrics makes sense. Colder air is harder to move through.

When I did my 1,024 mi, single tank, 2010 Prius test, I followed these rules:

• 1 minute start in park - long enough for catalytic converter to heat up and fuel tuning cycle
• 1 hour - minumum travel time to average out all warm-up energy loss
• 27 mph maximum speed - cruise control low limit that won't 'kick out'
• minimize, gentle stops - avoid brake shoe kinetic energy loss

Bob Wilson