How should EV drivers prepare for winter driving?

Question

On Monday night, a snowstorm in Virginia stranded drivers for up to 48 hours on Interstate 95. An op-ed this morning in the Washington Post argued that it would have been much worse if all the cars were EVs:

All else being equal, though, cars and trucks with internal combustion engines (ICE) would have the advantage in coping with a sudden challenge such as the I-95 fiasco. It is much easier to rehabilitate a disabled ICE vehicle. Rescuers can deliver gallons of gas in convenient jugs; gas stations are still far more numerous than EV charging stations; and ICE car batteries can be jump-started in minutes.

The article goes on to argue that because EVs aren't good at handling situations like this, people shouldn't buy them. But it seems that with a bit of preparation, being stranded in a snow storm shouldn't really be any worse for an EV than an ICEV.

A lot of common advice for what to carry in your car to prepare applies equally to an ICEV as an EV, but things like jumper cables and gas cans obviously don't apply.

So how should EV drivers prepare for severe winter weather?

Answer 1

Keep the vehicle nearly fully charged during cold periods (if not using LiFePO4 batteries then at 95% charge to avoid full charge damage) at all times. Not only because of possible need for lots of cabin heat, but also because the charging port can get stuck due to ice, meaning you need the range to drive the car to a heated parking hall.

If driving long distances, stop at 50% charge at a DC fast charger and charge to 90%. Above 80%, the charging rate becomes very slow so you need to pay for more charging minutes, meaning driving the car becomes very expensive, but you are better prepared for traffic jams due to snowstorms.

If you have an internal combustion engine vehicle, the worst case is you have only 15 liters of fuel and get stuck in traffic, needing to use the fuel for heat. It provides 150 kWh of heat energy if idling, but about half of that goes away in exhaust heat. So, realistically only 75 kWh of energy can be provided to cabin heat.

In contrast, if you have an electric vehicle, you nearly fully charged it (to 70 kWh), and drove only little (using 20 kWh of battery energy), you can realistically use about 40 kWh of energy for heat to avoid deep discharge. A COP=2.5 heat pump can provide 100 kWh of cabin heat with 40 kWh of electricity. That's better than the worst case in an internal combustion engine vehicle.

It's true that in ICE vehicles, you can bring extra fuel in containers. But assuming you don't want to do that, the nearly fully charged electric vehicle is actually better than the ICE vehicle whose driver is lazy in refueling (very typical), assuming it has a heat pump.

However, for non heat pump EVs the situation is very bad. You can provide only 40 kWh of cabin heat. Assuming you haven't yet purchased your EV, this is one major reason to stay away from fully resistively heated EVs.

Heat pumps need maintenance too. A good idea to do the heat pump maintenance at least every second year, if not every year.