I think this is the key question. If the issue is that a block heater is necessary for a start in extreme cold, I can see worrying about it, but if you are trying to squeak out a couple of extra mpg, it seems like a misguided effort.

There are propane powered block heaters available (not cheap):
http://www.servicemate.com/catalog/p...px?PartNo=8152

It seems likely that if you live where these extreme temperatures exist, a plug in outlet would be available.

 

Tom, you'd hope, but there isn't a plug-in available where I work. I park on an open lot with no wind protection; when I left yesterday evening, the air temp was 16 (up from 5 when I got in) and the FEH didn't go into EV until after 25 minutes of driving. I work at an environmental agency where a lot of employees have hybrids; it would make sense to have plug-ins available to warm up cars as needed. No dice. I can't wait till we get well below zero; I wonder if I'll stay above 25 MPG.

 

OK, so if I understand correctly, you don't have a problem starting, you want to improve your fuel economy. From what you said above, I'd guess the issue is more related to low traction battery temperatures. Maybe it would make more sense to heat the battery via the cabin, either before you start the ICE or after. How about a small propane heater like ice fishermen use, located behind the rear seat?

 

In that case, what about the extra Battery + Inverter idea & use an electric blanket on top of the rear battery?

 

Yea, I guess you could use something like this:

http://www.roadtrucker.com/12-volt-h...s-sheets-1.htm

and skip the inverter. I've got to wonder if the increased EV would result in a net energy save.

 

It's a bit strange, but it just might work!

http://www.warmers.com/ItemDetails.a...s=ProductSpecs

Forty 2 x 3 inch pads that will reach 135 degrees for seven hours. They don't say the watts, but at a buck forty a shot, they just might be worth it in the Twin Cities or Detroit during the dead of winter. Even if you needed two of them under the traction battery they would still be a deal.

Howzat for 'outside the box'?

 

The blanket/mat warmers have been discussed in another post. The best deal I could find was on a dog bed warmer at a store called "Big R's" in Great Falls, MT. The medium size was around $50-60 and will fits over the battery perfect. I was planning on picking one up for this winter and setting it up to plug in with my block heater that's already on a timer. I'm headed down there tomorrow for some other stuff (i.e., 42" LCD!!!!) so will be sure to pick one up and post an update on the install. I am also going to weld up a light gauge adjustable rad block for winter use.

 

Cool. Please share your design and experiences. My initial design of two card board pieces, each half the height of the radiator are working well. I'm thinking that if I modified the design to 4 pieces, each 1/4th of the height, they would all lay down flat (horizontal) when not raised. This would eliminate the need to remove them, even in the summer.

 

It's good to hear your design is still working...it's what I was going to be copying off of.

I have been too busy to even take a look at what kind of room we're dealing with, but another idea I've been thinking about is to use a louvered or shuttered type of design like you see on the exterior mounted ventilation fans. See pic below. It would be nice to, like you've done, have the ability to leave everything in place and simply open or close them as needed. Having it made from galvanized steel would surely make it last as long as the FEH. I've seen these at various used/wholesale farm/auto stores around here...maybe the fan could be separated and it would fit in without too much work.

 

There is not much room. You are going to have to use many rows of shutters because you don't have much room horizontally.