Tesla Owners Suffer Through the Polar Vortex While Solar Panels Keep Plugging Away

Below freezing temperatures means EV owners are suffering huge drops in their vehicles’ range

Chicago and much of the Midwest are still caught in the throes of ice, snow, bitter wind, and cold. It’s not the -40°F we saw last week during the polar vortex, but even now Chicago continues to suffer through extreme cold, this week seeing an average temperature around -1°F.

Tesla and other EVs Don’t Like Cold Weather

Jump on social media and you’ll see Tesla and other EV owners complaining and venting that the cold is cutting their vehicle’s range by 1/3 or more. With Tesla vehicles enjoying around 220 miles of range in good weather, a 1/3 drop means you’ll only have 145 miles at your disposal. That’s still enough for most commutes, but certainly disconcerting when you’re on snowy, icy roads and your available range starts to decrease more quickly than usual.

Due to the unique composition of the lithium-ion batteries that are common in electric vehicles, all EVs, like the Nissan LEAF for example, suffer from this cold issue. On January 25, Elon Musk even responded to the complaints on Twitter, claiming that improvements for cold weather conditions were coming in future software updates, though he didn’t go into specifics.

Of course, issues with cold weather aren’t just limited to electric vehicles. Gas-powered vehicles don’t like cold weather either. In cold-weather states like Minnesota, drivers routinely cover gas-powered engines in electric heated blankets to keep the engine warm so it’s able to start on the next frigid morning.

Just like any battery, the lithium-ion batteries used in EVs lose serious capacity during cold weather. You might’ve experienced this phenomenon if your flashlight batteries died on a cold camping trip. If you took them out and warmed them up in your hands, you probably were able to enjoy a few more minutes of light.

Lithium-ion batteries are the same. They perform best around 70 degrees F. Cold weather increases the electrical resistance of the components inside the battery. For EVs, this leads to less energy available to power the wheels and slower charging while plugged in. Exactly how much energy an EV loses depends on the model, temperature, and battery makeup.

While you really can’t do anything about your batteries’ cold weather performance, there are couple tricks to extend your battery life as long as possible on particularly brisk days.

All EVs include a system to system to cool the batteries on hot days and warm them up on cold days. To regulate the battery temperature, Tesla uses an energy-intensive glycol-based liquid cooling/heating system that is pumped through the battery banks.

These battery heating/cooling systems use precious electricity while driving. To save battery power, pre-warm your vehicle’s cabin while still plugged-in at home. While charging, your vehicle will also keep the battery pack warm, which means even less wasted energy and higher range.

Solar Panels Like Cold Weather

You might look out the window at the snow-covered yards and assume your neighbors are regretting their decision to install solar right about now. After all, it’s just so cold! Some even took to Twitter to express this idea (see below), but they’re dead wrong. Solar energy doesn’t work like that.

It might come as a surprise, but solar panels actually perform better in cold weather than hot weather. Why is that? Because solar panels convert the sun’s light to electricity, not the sun’s heat. Solar panels actually produce more electricity on a sunny, cold day than a hot, sunny day. Just take a look at this South Carolina homeowner’s tweet about his high solar production during the polar vortex:

Solar panels’s temperature sweet spot is 77°F. Anything above that temperature and they start to lose efficiency. The measurement of this loss is called a solar panel’s temperature coefficient, which typically falls around -0.40%/℃. In other words, energy production decreases by 0.40% for each degree above 25 degrees C (equivalent to 77 degrees F).

For context, at this temperature coefficient, a 300 watt solar panel on a roof that is 140 degrees F – easily achievable on a hot summer day – can only produce at most 258 watts. That’s a big drop!

This temperature coefficient doesn’t go the opposite way though. In cold weather, energy production actually remains high.

Of course, cold weather states also have to deal with shorter days, less sunlight, and more snow, so annual solar production in Minnesota or North Dakota is typically lower than in states like Arizona or California. But that doesn’t negate solar’s financial benefits. Even with lower energy production, installing solar still makes financial sense, as it’s cheaper than utility-sourced electricity.

So remember, it might be chilly outside, but if you’ve got solar on your roof, they’re still pumping away up there, producing electricity to keep you warm and cozy inside – and your Tesla charged up.

Image Credit: CC license via Flickr

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