It's below freezing outside, you own an electric car, you have a distance to drive that is close to your vehicle's maximum range.  What do you do?

For most the choice is simple:

  • transform into you super alter ego - "Popsicle Man" while you conserve energy
  • incorporate a little detour to a public charging station
  • hop in you 2014 Land Rover Range Rover Sport instead
Or, as demonstrated by commenter Stanislav Jaracz in New Jersey, you can install a diesel/petrol combustion heater for less than optimal plug-in driving days.

All the heat you want - all the time; and according to Jaraczs when used in a Mitsubishi i-MiEV, up to 75% more range on those extreme cold days over using your factory heating system.

In addition to the video Stan was kind enough to pass on some backstory on the heater and his experiences with the Mitsubishi i-MiEV:

My new (improved) Winter Driving Experience

It is well known fact that EV's have shorter driving range in cold weather, as much as 60% lower. Residents of California may not know (or feel) what I am talking about but here in Northwestern area, my fellow EV drivers know what I am talking about as this Winter has been particularly rough. And then come our Northern Canadian brothers with even lower temperatures. Let me throw a question: What source of energy do we use to heat our homes?

Stan's i-MiEV Waits To Be Driven In 21 Degree New Jersey Weather

According to National Geographic, nearly 60% of homes in the US are heated with natural gas, followed by electricity and oil. In addition, the US Census 2000 shows the colder the state the bigger proportion of heating oil. Electricity is used mostly in warm southern states such as Florida.

How come that we heat our poorly insulated EV's with electricity stored in precious battery packs? According to US Energy Information Administration, coal and natural gas fired power plants make over 2/3 in the US energy mix. These fuels are burned and the heat is converted to electric power at 30-50% efficiency, then transmitted to our homes while loosing around 6.5% and then losses during battery charging/discharging cycle. And then we convert the electricity back into the heat in our EVs. So, what is the reason we waste electricity to heat our EV's?

I was determined to eliminate the inefficient energy conversions / transport and burn the fuel right in my EV. This would also disconnect the competition between energy use for propulsion and heating, which would significantly increase driving range in Winter, while keeping all passengers warm and cozy.

Getting Ready To Heat Things Up!

My EV (Mitsubishi iMiEV) had a liquid heating system based on the gasoline sibling and to compensate for the lack of the ICE waste heat, the Mitsubishi engineers opted for PTC heater located under the floor. After reading blogs on and searching online, I have learned about parking heaters used in cold climates to keep truck cabins warm while saving fuel and engine wear & tear.

The major brands are Webasto and Espar. I was able to identify local distributors for each of these brands and obtained pricing and availability. However, paying over $1,000 prompted me to search for cheaper alternatives. Finally, I have taken the chances and ordered "generic" JP diesel parking heater, direct ship from China. Actually, this was a complete set including all brackets, bolts, wires, mini-timer, muffler etc.

I have made a plan for the installation but it had lots of unknowns. How do I anchor the heater? How do I wire the heater control? Can I incorporate it within the vehicle climate control? Several tests had to be done before comitting to remove the old PTC heater and install the new diesel heater. And, I would not be able to make it without the help of my fellow blogger John Annen who sent me detailed vehicle manual and gave me advice on a wiring solution.

To cut the story short, I was pretty lucky and replaced the heater in one day. The dimensions of both heaters were similar and I was able to utilize original brackets to bolt the new heater into the same place. Later, I have modified the wiring and heater control to be independent of the vehicle climate control as the operation was more reliable.

Burning Diesel To Heat The i-MiEV On Those Cold Days Enables Much More Available Range

My first impression was not so positive because the heater produces characteristic diesel odor. Before I realized that it is happening only at the start (and at shut down) I was experimenting with (bio)ethanol as a fuel. Although the heater still works with ethanol and it is essentially odorless, the performance (or Btu) was significantly lower. When I figured the smell is only temporary, I switched back to diesel.

The heater has two power stages, 2.4 kW and 5 kW. It starts at full power and when the heater fluid reaches 176 F (80 C), it adjusts the power stage to maintain the temperature within a defined window. The percieved heating intensity in the cabin is much greater compared to the original PTC heater and for most of the time, the lower power stage suffices.

Saving the battery power for propulsion significantly increases driving range even at very low temperatures. I was also able to direct the warm air into the battery pack to improve the battery performance as well. So, on a day when the temperature is 21F (-6C), the fully charged vehicle showed me 87 miles available. With the PTC heater, it would be maybe around 50 miles. The range estimate is much more similar to Summer, maybe 95 miles with the same driving history.

So, we can say that the diesel heater reversed about 80% of the Winter negative effect. And what is the (fuel) cost? The lower stage consumes 9.1 fl.oz./hr (0.27 L/hr), which translates into 380 MPG at my average speed of 25 MPH. In reality I am just finishing the first 5 gallon diesel can after 1700 miles. Having the vehicle modified, I can continue using it for the same (long) trips I got acustomed to in Summer, avoiding the use of ICE second family car.

In conclusion, my new Winter driving experience reasures me that the best way to heat the cabin and battery of an EV is via combustion process and electric powertrain is the best technology for propulsion. And, the heating does not have to come from a fossil fuel, it could be biodiesel, bioethanol, compressed biogas/syngas. I like to draw apparently unrelated comparison. When electric starter was introduced into ICE cars early in 20th century, it greatly enhanced value and practicality of ICE vehicles. And it was an inspiration from electric car. Similarly, combustion heater is an inspiration from ICE and it greatly enhances its value.

Stanislav Jaracz is a native of Czech Republic (former Czechoslovakia) and he came to the USA in 1998 to pursue study at graduate program in the Department of Chemistry, Columbia University in the City of New York. He has settled in NJ in 2007 working in consumer products industry as a technology professional. He began to think sustainably in 2010. His house is fitted with PV solar roof and high-efficiency natural gas-heat pump hybrid heating system. Influenced by the famous "Who killed the electric car" he acquired 2012 Mitsubishi iMiEV in March 2012, the first iMiEV sold in the NJ state.

Hat tip to offib!

Got a tip for us? Email: