ASK THE EXPERTS: Volt in Cold Weather

Intermediate

This summer I began leasing a 2017 Chevy Volt, which was supposed to go 50 miles on a full charge. I was pleasantly surprised to get up to 60 miles—until cold weather set in.

At below-freezing temperatures, the gas generator runs almost continuously, with mileage dropping as low as 19 mpg. Turning off the heating system to conserve battery power seems to help, but when the temperature is 15°F outside, there seems to be no way to force the Volt to use its battery storage below 70% SOC.

I have had the dealer check the vehicle and nothing seems to be wrong. A complaint to General Motors provided no further assistance. It seems that the Volt has been programmed to keep its battery charge above 70% SOC in subfreezing weather—but is there any workaround?

Peter John Moehs • via email

Your complaint is common among new Volt owners driving through a first winter in frigid regions. Volt drivers have long ranted, “The battery has juice! Why not use it no matter how cold it is?”

The answer is what General Motors (GM) calls “engine running due to temperature.” An Internet search for the acronym “ERDTT” provides detailed explanations of this feature and reveals many debates about it in online forums. In a nutshell, GM engineers made their best attempt at balancing total system efficiency with the comfort and safety of its passengers. While a lot of EV aficionados take great pride in avoiding any gasoline use, the engineers apparently believe that periodic use of the engine to keep the cabin warm—by using the heat it generates—is a good compromise.

There are a few things you can do to correct this. First, use the Volt’s dashboard menu to set the ERDTT temperature to 15°F, rather than the default 35°F setting. That should keep the engine off on all but the coldest days. Keep in mind that this is based on outside temperature, not cabin temperature. Start with home screen on the dashboard display, then go to Config > Vehicle Settings > Climate and Air Quality > Engine Assisted Heating. Then select “At Very Cold Outside Temperatures.”

You can also preheat the Volt’s cabin before a trip using grid or PV-produced electricity instead of the car’s battery or engine. Set the ERDTT to be disabled while the car is plugged in. Then, preheat your car via the key fob or OnStar app. Consider combining trips to minimize the number of times in a day that you need to warm up a cold car.

If it’s any consolation, the impact of cold weather on your Volt is relatively minor compared to what’s experienced by drivers of pure electric cars. Freezing temperatures can reduce an EV’s range by 40% or more. For drivers of first-generation EVs, the reduction can mean not being able to confidently complete a commute—and having to resort to driving a conventional gasoline vehicle. One of the reasons that GM installed a 60 kWh battery pack in its all-electric Bolt is to help commuters arrive at their destinations, despite the weather. Even with a 50% decrease, the car still has about 119 miles of range.

While it may look like your car has 70% of its battery charge remaining, that might not be the case. Dashboard systems displaying a state of charge—or estimated remaining miles—are notoriously inaccurate. That’s how they earned the nickname “guess-o-meters.” It’s difficult to accurately measure the dance of electrons.

Finally, keep in mind that all cars—not just hybrids and EVs—take an efficiency hit on freezing days. Yes, it’s annoying to see energy in your battery not getting used, but your Volt—even when cycling on the gas engine to warm up the vehicle—is among the most efficient vehicles on the road. Your annual consumption of gasoline is remarkably small, even if it takes an extra gallon or so to make it through the winter driving season.

Brad Berman • Home Power transportation editor

Comments (9)

Todd Hoitsma's picture

Absolutely love driving my volt in "L" rather "D". Some call this "one - pedal - driving": brakes are seldom needed as regenerative system slows car down as you left off the "gas" pedal. With studded snows volt is a rockstar in the winter...even with the lower electric only range. Heated seats are critical on electric cars winter!

John Webb's picture

I've never had the problem described. My '13 Volt uses every electron in the battery bank every time It gets driven, unless I am driving in mountain mode.
Kansas winters can see temps below zero and I've seen "engine running due to outside temperatures" on the display many times, but it always depletes the juice in the batteries first, before going to generator power.
The cabin seems to get warmer when the car has switched to generator power, and after reading some of these comments I now understand why. The heated seats go a long way to keeping me cozy until the genny kicks in.
My commute is 50 miles one way, so the genny gets used a lot. I still average around 55 mpg.

James Eddy_2's picture

I get to warm with the seat warmer on low. I never paid attention about the cabin getting warmer, but it makes since because it’s using the generator heat to heat the cabin instead of the electric heater.
We get well below zero here in Northern Michigan so in the winter I use all of the battery available too but only 1 or 2 miles on the generator. I keep mine set at 35 degrees to run the generator to keep the battery warm the generator doesn’t run at a high level.
Sounds like you love your Volt also!

James Eddy_2's picture

I have had my Volt since November of 2012. Yes my range drops in winter cold weather. But in the summer I can go 6000 to 8000 miles without the engine running. The Volt tells me it will run a Twenty minute engine maintenance when I park it.
I have over 100,000 miles on it. I live 30 miles from work and I have a charger at work and home. I can’t say enough good things about it.
The engine running during cold weather is a small price to pay for not having to fill up a gas tank 1 to 2 times a week Compared to my old car.

Daniela Gadotti's picture

Thre is a non electronic reason why EVs have less range in winter: in frigid climate one likely changes the tires to a winter set with higher rolling resistance. This alone can rob you of 20% of your range before any considerations on conditioning cabin and battery temperature and the battery ability to accept and store charge.

Todd Hoitsma's picture

Cold weather range for a Volt (or equivalent) does drop in winter. But even factoring the loss in winter range (as shown by the reading of 19 mpg) EVs still are much more efficient than standard internal combustion cars. If I zero out the instantaneous MPG readout on my gas car when it is very cold (say 5F) to determine the fuel used to warm it up etc, the MPG can be as low as 4MPG on short trip of in town stop and go winter driving. My Volt was great to drive all winter even being left outside, un-garaged at 0F or colder.

Bob Peloquin's picture

Another reason for pre-heating an EV or hybrid that uses lithium batteries is that lithium batteries cannot be recharged when below 32 degrees F. They can still be discharged but I've read that their below-freezing chemistry does not support charging till warmed above the freezing point of water.

This could be an issue for Prius Prime owners and Chevy Volt and Bolt owners if their lithium batteries have similar limitations. The engine may start on these vehicles to drive the car forward but it can't charge the battery pack till it is warmed by either engine coolant or cabin heat (depending on design) to above 32 F.

tyme2par4's picture

The Volt and Bolt have liquid cooled and heated batteries. When they are running or plugged in, the system will keep the batteries from getting too cold. If left unplugged for an extended period of time in subzero temps, the Volt will automatically start and run on engine power until the battery has warmed up.

Bob Peloquin's picture

Maybe the lithium pack on the Prius Prime has a heater - I don't know. I suppose Toyota knows what they're doing and have it handled. It's just something we have to keep in mind I guess. Heat and cooling must be supplied to lithium batteries while in use or charging.

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