Living Sustainably
in the shadow of climate change

March 2015
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Maximizing fall/winter range in the Volt
Filed under: General, Electric Vehilces, Our Chevy Volt
Posted by: Guy @ 4:51 pm

It is mid October here in Maine, and the leaves are turning.  We had our first frost last night and the daytime temperatures are dropping into the 50s.  We are noticing that the electric range in our Chevy Volt is dropping as we begin to use the heater more.  In the summer without using air conditioning we were getting  an electric range of 45 to 48 miles -  this is now dropping into the upper 30s as we use the heater more. 

We have two strategies that we are using to extend our electric range, one is that we can use the remote control from inside the house - well over 100 feet away - to turn the car on while it is still plugged in to the charger.  This way we can use “shore power” to warm the car for 10 minutes before we get in it.  We have to remember to leave the climate control in “comfort mode”  when we park it and plug it in so that it will warm the car quickly when we power it up remotely.

The other strategy involves parking the car out in our parking area to the north of my solar powered workshop.  This way the Volt can absorb some free heat from the sun in the morning and afternoon to warm the vehicle.

4 Responses to “Maximizing fall/winter range in the Volt”

  1. rj Says:
    Does the Volt use straight electrical resistance heating? Or does it use engine heat or some combination of the two? Seems like a derivative of the new super efficient heat pumps would make sense, some approach 400% efficiency per kw used and maintain an acceptable performance down to zero F.
  2. Guy Says:
    rj I believe it uses resistance heating in EV mode, but can also use waste engine heat when that is running. On very cold days the engine will run to provide heat to the battery to maintain a safe operating temperature, and any additional waste heat goes to the cabin. I’m not sure that heat pumps could be scaled down in size/weight/cost enough to be effective in a vehicle. I have certainly considered a heat pump for our home.
  3. rj Says:
    A heat pump is nothing more than a normal AC system with a reversing valve which change the process to moving heat from the outside to inside. Since the auto manufacturers already have electric AC compressors it would be relatively easy if they wanted to implement a heat pump. Most of super efficient Japanese mini-splits employ variable speed compressors and electronically controlled expansion valves to produce superior results. Toyota and Nissan could call their buddies down the road. I am sure GM could figure it out. Probably the biggest roadblock is initial development costs and a little more recurring costs for a variable speed compressor and the reversing valve. Conventional heat pumps require a logic board for defrosting that straight ACs do not need, but an existing automotive ECU could easily add that logic.
  4. Guy Says:
    rj, I agree that you have all of the theory right, but I still think the issue in scaling heat pumps for automotive use comes down to size/weight/cost issues.  Also, we have been noticing at this time of year that the icons on the dashboard often show both heat and AC being used simultaneously. I believe this has to do with humidity control and defrosting. I don’t think a single heat pump could provide both options for humidity control AND heating. I may be wrong though.