Too Cold for EVs?

by Ben N on January 14, 2016


After a strange, warm, “El-Nino” start to the winter, temperatures have suddenly plummeted. Which begs the question – How cold is TOO cold for an EV?

I bought my Mitsubishi iMiEV electric car on the day of the first snow-storm of this winter. Other than that, we had unusually warm weather all the way past Christmas. Until just recently, when temperatures dropped.

This Monday, the thermometer said NEGATIVE 8 °F when I woke up. I was working that day at a location 23 miles away. The Mitsubishi has the shortest official range of any battery-electric car in the United States at 62 miles. But the government testing rates cars under TEST conditions, NOT Wisconsin winters! Batteries don’t perform as well when cold, and having snow on the road means more energy used to turn the wheels, further reducing range.

IMG_7389The other big issue with this particular car is that is has a rather poor heater. Other than using electricity to create heat, the iMiEV otherwise has a heating system identical to any ICE (Internal Combustion Engine) vehicle! A heater fluid (we would normally call it coolant, but in this case it’s not used for cooling at all) travels through uninsulated hoses from the electric heater to a heater core, where a fan then blows air into the passenger compartment. The heater also produces a lower TEMPERATURE than most ICE heating systems. So, even when it’s working full blast, there’s still not as much heat as a person might be used to in another vehicle. And, due to the fact that it’s a liquid-based system there’s still always a warm-up time. You could drive for half an hour with the heat off, and when you want to turn it on, it STILL has to warm up.

The heater can also draw up to 5,000 watts. That translates to over 6 HP. In typical driving, the heater can use a quarter to one-third of the total energy of the car – decreasing range by that amount. In bumper to bumper traffic, or while stopped, the heater can actually use as much or MORE energy as the motor!

So, when I left for work on Monday morning, I used the heater as little as I could, and drove at very reasonable speeds. When I got to the work location, my battery charge was down to just below half. If I drove the same on the way home from work as I did to get there, I wouldn’t have enough energy to make it! Fortunately, I had two options. One was to simply take a different route. By taking back-roads, I could drive slower. Driving slower really helps increase range. The other thing is that I did have access to a 120V outdoor electric outlet at this location. I rolled out my extension cord and plugged-in the car using my “Level 1″ charger.

When I was ready to leave, I did have some additional battery charge, but not as much as I had hoped. Level 1 charging is significantly slower than level 2, and I think the cold was limiting my rate of charge as well. At least the battery was now in the upper half of the charge range. I still had to work another job for the evening. By that time, it was also dark, it was turning into rush hour traffic, AND it started snowing.

IMG_6539One of the reasons why I bought this car is that it has a “Quick Charge” port. Using the CHAdeMO charging system, the car can be recharged to 80% in 30 minutes. There’s only one CHAdeMO charger in my area, but it’s free, and conveniently located just off the main east/west freeway in the area. While I could make it home, driving slowly and leaving the heat off, I thought it would be nicer to have some more battery charge so that I could use the heat and drive at what speed and route I would like – just like any gas car would.

I turned the heat on to warm up and headed to Marshall Autobody in Waukesha, Wisconsin to use the Quick Charger. It was a little out of the way, but I would more than make that up when I charged.

After I arrived, I plugged in the charger and ……   Nothing happened.
Hmmm. I thought I was doing it right. Press the button on the screen, plug in, make sure that red emergency-stop button is reset…. Nope, it just didn’t work.

Only a few moments after I arrived, another iMiEV pulled up. This was pretty strange, as I had never run into another one in the wild yet. I said hello, and taking a wild guess, asked “Does your name happen to be Barb?” In fact, it was Barb. I had seen her name on an electric car group list, and there’s just not that many iMiEVs out there. We weren’t able to get the CHAdeMO to work with her car either. Likely, it was some sort of an issue due to the cold weather.

I did notice that in Barb’s car, she had a fuzzy steering wheel cover and a lap blanket. Unlike mine, hers was just a plain blanket, not an electric heated one. Just like me, she was bundled up in the type of clothing one would expect to see on somebody spending hours outside in the extreme cold. I recently upgraded my headlights to LED. Barb’s car still had the stock halogens, so I used the opportunity to snap a photo comparing the two.


Barb left, and was traveling the opposite direction as I, so she was hoping to be able to make it another CHAdeMO station off to the southeast. I plugged my car into the J1772 Level 2 charger, which worked great, for a short while while I reported the faulty CHAdeMO to the owners and posted a comment to PlugShare. Elaine from Marshall was already outside on the phone with a tech before I even left.

Back on the road, it continued snowing. I ended up at a net LOSS of energy trying to get a quick charge. The location was a few miles out of my way, and I was running the heat while driving over there. To make up for it, I took the side roads. Due to the snow, all traffic was much slower, which was good for my range.

After I arrived at the other place I would be working that day – a municipal building – I parked at the Library. There are outside 120V electric outlets there. While I would only be there for about an hour and a half, I figured any energy I could get would be good. I parked at the last space in front of the Library and ran my extension cord across the sidewalk. Because it WAS the last space, I figured there would be little, if any, foot traffic over my extension cord. In the future, I intend to carry an outdoor rug that I can place over the extension cord, preventing the trip hazard. The last thing I need is for librarians to be mad at me!

When I was ready to leave, the car was still plugged in, and there were no hate notes or lawsuits. Additional range was minimal. I again took the side roads and finally headed home. Once I was about 3 miles from home and saw that I would still have plenty of battery to make it the rest of the way, only then did I turn the heat back on. Getting home was otherwise uneventful. Once there, I parked, plugged the car in, and said good-night.

During my journey that day, most of my body was a pretty good temperature. However, my toes were COLD! After stepping around in the snow trying to get an unsuccessful quick charge, my footwear was then wet, and my toes were PAINFULLY cold. The electric lap blanket works well. Everyone should have one in their car, it’s pure luxury! However, it doesn’t cover my toes, as I need those for operating the vehicle. Likewise, my really good winter boots are large enough that I don’t trust NOT hitting the brake and accelerator at the same time with them. Even if my entire body is covered with arctic gear, I still need the heat to run the defroster – simply for visibility.

IMG_7390The next day, I upgraded my windshield washer fluid. So much salt gets used on the roads in my area that windshields get caked with dried salt streaks. When I would use the washer fluid, it would just freeze right to the windshield! In a car with a nice HOT defroster, it might not be an issue. I stopped at the auto parts store and was glad to see that the fluid rated for down to -25°F was on sale. I drained the blue fluid and poured the orange fluid in it’s place. When I had stopped at a gas station earlier to use their squeegee, the purple washer fluid in the bucket was frozen into a grape slush. So far, the orange washer fluid seems to be working well.

Now don’t let me get TOO down on the heating system in the car! The driver’s seat is heated, and works great! The car also has a “pre-heat” system that works pretty well. If the car is plugged in to wall power (which it usually is from charging the night before) a press of a button on the remote turns on the heat, and gets its power from the wall, instead of the battery, so I can leave with NOT only a full battery pack, but a warm car as well!

So, on a short winter trip, the car can be preheated and the heater can run the whole time. It works great AND doesn’t use a single drop of gasoline. Win/Win for everyone. BUT, a longer trip means serious compromises with comfort, just to make the car still go the distance I need it too. Not so fun!

Now keep in mind that it’s the combination of a small battery and sub-par heater that makes it so tough. For example, a Nissan LEAF has a larger battery pack, all seats are heated, and at least some of those cars have heated steering wheels. The LEAF also has improved insulation vs other Nissan cars. (The iMiEV appears to be completely uninsulated!) The newer LEAFs use a more efficient heat-pump system instead of resistive heating. While I have heard of complaints by LEAF owners of the shorter winter range, I haven’t heard of it being nearly the issue that it is with the Mitsubishi iMiEVs.

So, I am considering a “Parking Heater”. (EDIT: I did install one. See it here.) That is a liquid-fueled heater that heats the engine coolant, so that a car can have its engine and heating system warmed up WITHOUT running its engine or using an electric block heater. There are also air-to-air versions which just directly heat air for the passenger compartment. They are popular on semi-trucks with sleeper cabs, so that the driver can stay warm without idling a 500 horsepower engine.

Several iMiEV owners in cold climates (Canada, Finland, Russia, even New Jersey,) have successfully installed these heaters with fantastic results. My “knee-jerk” reaction to the thought of adding fossil fuel to an EV was “No WAY! You aren’t gonna put petroleum in MY renewably-powered electric car!” But after reading through some forum threads, it actually makes a lot of sense. Here’s why – it’s APPROPRIATE use of fuel. The problem with most internal combustion engines is that they are SO inefficient that heat is the majority waste product. Every car needs a large radiator just to keep the vehicle from overheating! Of course, in the winter, some of that “waste heat energy” can be directed to defrosting a windshield or keeping feet warm.

5KW-12V-font-b-Diesel-b-font-Liquid-Parking-Heater-webasto-Eberspaecher-water-heater-RV-heaterLiquid fuels are GREAT for creating heat.

Using a small, efficient, PURPOSE BUILT device to only create heat frees up the battery system to maximize energy for travel. Since there’s a reduced load on the battery, battery cycles are also reduced and battery LIFE is also extended.

Also, nothing says that I have to use petroleum in the heater. Bio-diesel, E85, and straight ethanol all have potential use in such a system. A friend of mine brews his own ethanol from scratch (yes, he has the ATF license!) I’m sure I could get a few gallons per year of automotive moonshine from him.

The heater would be plumbed in such a way that electric heater and electric pre-heat feature would still work properly. The finished system would in fact be a Hybrid Heating System on an Electric Car.

So, now my only real question is whether I want to purchase the diesel or gasoline version of the heater. I’m leaning towards gasoline, as it’s easier to get ethanol than bio-diesel in my area. Even if I DO use petroleum, and it lets me use the electric car, where I would otherwise need to use a fossil-fuel powered car, it’s still a significant net cost and carbon savings!

And, on the upside, as I write this the sun has finally come out and temperature has warmed up into the 20′s.

‘Til next time, stay warm and charged-up!

PS: One feature that I really haven’t been thinking about is the heated side mirrors. I have had ZERO issues with ice or snow on the side mirrors. The mirror defrosters work so well, I just don’t thing about it. They work great!

PPS: In the beginning of February, 2016, I received and installed my fuel-burning heater. You can read about the installation, mostly through a series of videos at:

{ 1 trackback }

iMiEV Heater Installation
March 3, 2016 at 4:48 pm

{ 9 comments… read them below or add one }

1 Aaron January 15, 2016 at 8:51 am

Thank you for your article. I live in Michigan and I’ve been wondering about a few of these issues. I currently drive a 08 Versa and I’m squeezing out every ounce of life from it before I switch to an EV. I had considered picking up one of the 90′s model EV’s from Solectria and converting it to Lithium ion batteries. While the interior technology was basic, they already had diesel heaters installed.

Just out of curiosity have you considered insullating your vehicle? Considering it’s size you probably could remove the interior paneling (a chore I know) and use a small 202 spray foam kit to create a 1/4″ to 1/2″ layer. That might help a bit. Or you could use a soft roll foam product

2 Ben N January 17, 2016 at 7:28 pm

Hi Aaron! Yes, I am planning on insulating the doors. I figure that either a roll foam material or a reflective radiant barrier insulation should work fine. I don’t think it’s something I would get to until spring though. That not really a project I want to be working on in my driveway out in the cold!

Other iMiEV owners have insulated the doors, with a side benefit of the stereo speakers sounding better as well!

I might also try insulating the roof, although it would be quite a bit more work to remove the headliner!

3 JP White January 18, 2016 at 12:20 pm

As a new EV owner you have learned the lesson I learned as a new EV owner. Driving out of your way to get a quick charge often results in a worse situation than you started with. When faced with a charge that may or may not get me home, I simply drive slower and take the shortest route. There are often several L2 stations on the route that can be used at a pinch which can add that extra few miles quickly enough should slow driving not be enough to get you home.

More often than not, driving slowly and taking the shortest route is all that’s needed.

4 lanny smith February 14, 2016 at 6:34 pm

i ask before about your heater and the only ones i could find are 650$.also i need HELP. i have the contactor but no diode. all the guys say mine has a diode, yea fine, where. it has in and out for the wires and (1) wire for the on off switch, but, how do you wire it in and what size is it.

5 lanny smith February 14, 2016 at 6:58 pm

also we had a vw with a gas heater. we used a motorcycle gas tank in the front to hold the fuel to run it so that might be an idea for you.

6 Ben N February 15, 2016 at 7:58 am

A motorcycle gas tank would be too big to fit under the hood in the iMiEV. I did see a moped tank through an online salvage place – looks just like a motorcycle tank, but smaller! I did want something that would look relatively stock and fit under the hood. In the end, I purchased a small and inexpensive 1 liter fuel tank. 1 liter fuel tank for heater system.

7 Ben N February 15, 2016 at 8:04 am

My heater was a little over $500, once tax and shipping were involved. You may be able to find a less expensive heater by searching salvage yards.
What contactor are you speaking of? If it’s a main contractor for a DIY electric car, you usually just need to run 12V to the the small terminals, but I can’t tell you for sure without knowing more about it. Questions like that are great to post (with a photo to show the device) to web forums like or That way, you have a large number of people to help out, and usually pretty quick responses. The instruction manuals for motor controllers usually have good information on contactors as well.

8 Tim Mende February 25, 2016 at 5:29 pm

just love your story. I recently purchased an I-Miev also, its an ES not the Se
like yours though, so no level 3 for me,found it at used
car dealer who couldnt sell it for 8K with 5500miles.
I Dont drive it below freezing also. You cant keep using the level 3′s
as they say your battery will go bad. wonder if u can replace
starter battery too with optima or similar?

9 admin March 3, 2016 at 9:23 am

The iMiEV batteries are more robust in a lot of ways than the LEAF batteries. Charging with CHADEMO isn’t an issue, unless your are doing it multiple times per day in hot weather or some other craziness.
You certainly COULD replace the starter battery with an Optima, but I don’t see any advantage to it. I do have a friend who not only moved his battery, (to under the back seat) but also upgraded it with a lithium 12V battery.

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