# Catalytic Heaters



## Mastiff (Jan 11, 2008)

I was thinking about what would be a better solution for heating an EV than using the batteries, then I looked to my left and saw my propane house heater and it struck me.

A small propane heater could quickly warm an EV and if safety is a concern they sell Catalytic Heaters that have no flames:
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200326072_200326072

Propane heaters are quick and pretty efficient.

I don't want to start a flame war here, I know not everyone would be happy about placing fossil fuels back into their EV's but with current battery technology if you need to use your heater all the time an electric heater is just taking range and performance away.

I found this topic:
http://www.diyelectriccar.com/forums/showthread.php?t=5977&highlight=Propane+Heater

I learned Mr. Sharkey has an EV with a propane heater, he uses an ESPAR heater:
http://www.espar.com/html/applications/automotive.html

This seems like a cheap solution for providing heat and keeping your EV's performance.

I'd like other people's opinions on this, it seems there hasn't been much discussion on the topic.


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## xrotaryguy (Jul 26, 2007)

Reminds me of the heaters that vw used to use in their air cooled cars. Theirs ran off of gasoline though. I'm sure that this would work very well. It doesn't take much propane to heat car, so you would probably not need to buy the stuff very often at all. 


The down side is that this kinda defeats the purpose of an electric car doesn't it? Not only that, but now you will have to plug in the car all the time, check and maintain the batteries if you're running flooded units, AND watch that propane tank to make sure that you're going to have heat. If it were me, I would just try to keep it simple and use only one power supply.

If your in-dash heater pulls too much current, and a smaller heater will not warm up the car, you could consider a heated seat. some of these units will actually cool the seat in the summer too, so they're really quite useful. One could use something like this and a smallish heater in the dash to keep the windshield from frosting up.

Again, if we're all trying to go electric, then using propane to heat the car just doesn't make sense... to me


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## Mastiff (Jan 11, 2008)

Aye your probably right, guess we just need better (cheap) battery technology already


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## xrotaryguy (Jul 26, 2007)

I wonder how hard it would be to install a windshield defroster similar to a rear window defroster. I have seen many late modes cars with coils adhered to the windshield at its base. I guess the coils heat up and defrost the bottom of the window directly and then perhaps radiated heat makes its way up the glass to defrost the rest of the windshield. Perhaps a rear window defroster kit could be modified to work in this way. Then, one would simply need to purchase one of those electric seat heater kits to keep his buns nice and toasty.


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## MJ Monterey (Aug 20, 2009)

xrotaryguy said:


> I wonder how hard it would be to install a windshield defroster similar to a rear window defroster. I have seen many late modes cars with coils adhered to the windshield at its base. I guess the coils heat up and defrost the bottom of the window directly and then perhaps radiated heat makes its way up the glass to defrost the rest of the windshield. Perhaps a rear window defroster kit could be modified to work in this way. Then, one would simply need to purchase one of those electric seat heater kits to keep his buns nice and toasty.



The electric Rav4s had electric defroster and I have seen add on defrosters that are installed like window tint. Not sure how effecient the aftermarket/add-on are.

For a defroster you may want to check rv and van suppliers. A few have small 12v glorified hair driers to defrost windows in the back and sides.


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## Woodsmith (Jun 5, 2008)

I thought about an Eberspacher cab heater, as used on trucks, to run off biodiesel. But apart from the cost it would mean sorting out a fuel tank, filler and exhaust as well as plumbing in hot air into the cab or using it to put hot water into the existing heating system.

I decided in the end to go with a heating element in place of the heater core and will make something up to do that.
The decision was partly to do with the existing core being blocked and requiring a change but also I was thinking that if I was to heat and pump water then it is added complexity and a delay in getting heat to the screen.
I could pre heat the water as part of the charging time but again more complexity and needing to store an insulated container of hot water and antifreeze.

Some modern cars have heater windscreens with a very fine heating wire on the surface. Not easy to make for an older car even using the old self adhesive rear screen heaters as the wire is too thick and visible.


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## Stunt Driver (May 14, 2009)

I would strongly support heating by propane or gas. 

EV is about efficincy, and not just about saying NO to gas. Heating is MOST efficient with fossil fuels, and driving is efficient with electricity. So let's keep right things right! If electric only is the principal - get that *AC unit to run in reverse*, that is 2x efficient as resistive heater. I think Aptera will have such heating/AC combo unit. 

But If you only need 2 gallons of gas to heat up car for the whole month - that is enough gas-free.

Besides, most of places don't need this year round. You'd only burn gas when its cold and your batteries being hurt the most. As for cold climates - EVs will never mass evolve without good supplemental heater system.


In Oregon winters are very mild, so I"m using tiny 100W airheater to keep windshield clean, and seat warmer to keep butt happy. Also, car is parked in garage and I run 110v heater in car for 5 min before I drive it to work.


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## JRitt (Sep 29, 2009)

Here is an option that you can buy for ~$150. It puts out 10K btu and uses a heat exchanger so the gases and moisture stay outside (provided you mount it outside the cabin). You can also get adapters to refill the small propane bottles from a larger 20lb cyl that you can keep at your house to keep the operational cost low.


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## Stunt Driver (May 14, 2009)

nice for emergency heating, but surely difficult to use - whatever is insalled, has to be fully electrically controlled, so you turn it on with a flip of a switch, and make sure it's off with ignition. 
Probably in colder states it's possible to get used hydronics - i know at least Range Rovers use them in Russia on diesel engines to keep temperature up when it is -20C outside


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## PhantomPholly (Aug 20, 2008)

Don't do it.

If you leave the windows open enough to vent the CO (carbon monoxide, causes coma if too much inhaled), you'll have to burn a LOT of gas to keep warm.

Used a very small Coleman propane catalytic heater once flying home to see mom. The "normal" heater in the plane isn't good much past 32F unless I have strong sunshine coming in the canopy. On this day, it was -12F on the ground up north, and I had to fly at 11,000' to stay above some nasty snow storms. At 3 degrees F per 1,000' lapse rate, it was -45F at altitude. I was bundled like Nanook of the North and the heater worked great but gave me a headache (natures way of telling you are breathing poison). So it was bake/freeze/bake the whole way.

Point being: Use electric heat and keep the windows shut. You will use less total energy and pollute less and no risk of killing yourself.


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## Stunt Driver (May 14, 2009)

i would argue that at 11000' you get poor burning due to lower air pressure, but would agree overall. Even if heating by fuel - it must smoke to outside.


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## PhantomPholly (Aug 20, 2008)

Stunt Driver said:


> i would argue that at 11000' you get poor burning due to lower air pressure, but would agree overall. Even if heating by fuel - it must smoke to outside.


Well, ambient air is about 30" at sea level and 20" at 11,000'. Burns just fine, or else I'd know 'cause that big fan up front would stop turning and I'd start sweating...


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