# cheap (free) heater for low-cost conversions



## JRP3 (Mar 7, 2008)

So we lose the space for batteries that would have been left by removing the gas tank, and we get to carry around all that water weight? There is plenty of room in the tunnel for LiFePO4 cells. Good luck with the patent


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## Stunt Driver (May 14, 2009)

read my title better - *for low-cost conversions*

there had to be a reason why it's only for low cost? Maybe because low costs don't have LiOn batts? 


ps and trust me, on Fiero - getting even Li batts in tunnel is not fun, but it's one of a kind car.
ps2 - 1KWh per 40 pounds - that is definitely better capacity than LA batteries. And I believe not much worse than Li Fe PO4


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## JRP3 (Mar 7, 2008)

Stunt Driver said:


> read my title better - *for low-cost conversions*
> 
> there had to be a reason why it's only for low cost? Maybe because low costs don't have LiOn batts?


Good point.



> ps and trust me, on Fiero - getting even Li batts in tunnel is not fun, but it's one of a kind car.


I know, I'm doing a lithium Fiero right now  I think I can get 10-12 100ah cells in there without too much problem. Don't know if there is much room around the tank to super insulate it though, pretty sure there isn't.


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## samborambo (Aug 27, 2008)

Stunt Driver said:


> ps2 - 1KWh per 40 pounds - that is definitely better capacity that LA batteries. And I believe not much worse than Li Fe PO4


Not quite. Specific heat capacity of water is non-linear and is less than half the capacity at 90deg.C compared to room temperature. If you can deal with the temperature difference of 50deg from hot to cold, you'd need at least 80lbs of water for 1kWh. At the cold end, though, trying to warm the car from a 45deg source won't be very efficient at all. I would half the temperature difference between hot and cold to maintain thermal efficiency but that would double your water heat storage to 160lbs.

1kWh of lead acid to 80%DOD is around 70lbs and US$250. You'd probably blow that money on pipe fittings, emersion element, tank, pump, control circuit, etc. Also the hot water tank wouldn't be as robust as a simple air heating element.

Sam.


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## Stunt Driver (May 14, 2009)

*JRP3* - about 10 cells in tunnel - I really hope you can, but from visual - it looks not very tall, and narrow at top. If put on side - probably a few, but freaky. Anyway - wish best luck, and DO post pics when ready!

*samborambo* - I would appreciate link explaining that, because that is not what I believe. And honestly it's been a while since studied that but Wiki says it's nearly linear, even increasing a bit.
http://en.wikipedia.org/wiki/Properties_of_water#Heat_capacity_and_heats_of_vaporization_and_fusion
So for 50C wate dT up to 95C - it's 8 mega J.
ANd from here - http://www.convertunits.com/from/kWh/to/joules
I get that 8*10^6J is 2.2KWh.
So not that bad, huh?


Also I believe 80% is not really possible on LA, from my driving experience on tracksion pack - so you'll need another heating pack? And to get 1kW of power from 12v batt - you'll need to pull 100A constantly, or go to more batteries. 

Yes, ideally, you have a fat pack and get a heater. It is just much more expensive.


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## Stunt Driver (May 14, 2009)

And trust me, guys, first time I heard about this - i thought this is most stupid idea. But suggest me any other REAL way to get warm for 30 min at reasonable cost with safely and control?

i hate idea of boiling water myself, and yet far from implementing it)

BUT - I found RV water heater - 6 gallons, runs on propane. I can loop that to my heater, and would probalby need $4 of propane a month. Just 6 gallons seems a bit too much for me - space and weight. For the same reason gas tank seems not perfect. And i'd prefer electricity.

So if I will find electric water heater tank of 2-3 gallons that fits in tunnel, has heating element and thermostat there - I may fall for this sin. like this one, just if found used for $10-$20 http://www.pplmotorhomes.com/parts/rv-water-heaters/rheem-water-heaters.htm


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## Guest (Nov 10, 2009)

Instead of water you could use oil. Holds heat better. Insulate and circulate. Could be good for a drive. Might not last all day but for the first drive it should be good. Would not need near as much oil as water. We use a nice cheap oil radiator that is powered by electricity. I still like the use of ceramic heaters put in where the old water heater was and use the stock fan to circulate the heat. Cheap and easy. Plenty of folks doing it. Most likely cheaper than all the plumbing and oil and heating element and remember you still pay for the cost. Not free. Most likely not cheap either. One extra good 6 volt battery should do the trick. Maybe just use your pack voltage at low amps. Should generate plenty of heat and not take too much from your distance. I am planning on that myself. 

Pete


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## Coley (Jul 26, 2007)

I use a small oil filled heater that is on a timer and comes on 1 hour before I go to town.
Car is comfy and the heater give off heat all the way to town.
If the sun is out, car stays warm all the time it is outside.
Simple and very cheap.
I buy the heaters for $5-10 at household sales.


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## JRP3 (Mar 7, 2008)

You could try this for some low cost heat as well


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## yammel (Nov 4, 2009)

Post 203 in this thread seems to be what you are talking about but just a tankless version. I will try this setup myself.
http://www.diyelectriccar.com/forums/showthread.php/brians-next-ac-lifepo4-ev-35419p21.html


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## electromet (Oct 20, 2009)

JRP3 said:


> You could try this for some low cost heat as well


LMAO! That's thinking outside the box. You'll just have to figure out how to get around the annual emmissions test. Perhaps a catalytic converter?

Mike


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## JRitt (Sep 29, 2009)

you could heat the car before you get in it with a portable ceramic heater set on a timer then it will not take as much heat to keep it warm


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## Zemmo (Sep 13, 2007)

Here is something that I have thought about before. It is a 120 volt AC powered heater. A simple timer to turn on before you leave for work would do the trick, no extra weight and simple.

http://www.warehouseautoparts.com/Specials/Kat/Kats_37100_interior_900_watt_heater.htm


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## Jan (Oct 5, 2009)

Anyone tried a heat pump in combination with the 'hot' water output of a water cooled motor and/or controller?


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## Stunt Driver (May 14, 2009)

Zemmo said:


> Here is something that I have thought about before.


well, I am using 120v heater in the car now while having breakfast, but i just wish i had a little more warm air while driving.

And I think I'll give up some juice to install ceramic heater finally, BUT - it will be double wired to 120AC as well. So before takeoff from home, of from charging pole at work - i will run that heater, in place of stardard core, from AC, which should warm up car and all venting/ducting. 

Got one from CL yesterday for $10. It gives out 1300W on 115AC, and has half-power mode at 700W. I'll keep the switch nearby, so even on my 72V i will be able to choose.

And timer is a good idea - charging stations are free so far, and got to take advantage of that! I'd set timer to start heating car 15-30 min before I come back @ 700W - this won't overheat car but will warm it up. This assuming charging will be mostly done by then, and so heater will not trip the socket.
Or maybe even keep thermostat to be safe.


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## grayballs (Aug 27, 2008)

Jan said:


> Anyone tried a heat pump in combination with the 'hot' water output of a water cooled motor and/or controller?


 
'Don't know how 'low cost' this alternative would be. 
The Danfoss units, I've played with, while not cheap, are effective units, when sized properly. 
http://www.rparts.com/Catalog/Major_...ss/danfoss.asp 

I suppose an existing auto AC unit could be modified to cool the motor and controller and put the heat in the cab, and you can rework the heater box to vent to the outside during the summer. We plan to use the diverter for the defrost, for cabin heat, and instead of redirecting it to the floor we will duct it outside when not needed. These units use a lot of power, though.
I'm still not convinced that there is enough heat available from the motor and controller, so we will look for other sources (outside air?)


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## alvin (Jul 26, 2008)

Just warm some bricks in the fireplace and place them on the floor
with a towel over them.


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## Stunt Driver (May 14, 2009)

alvin said:


> Just warm some bricks in the fireplace and place them on the floor
> with a towel over them.


it is actually better to warm them in the office, while located next to heater, and then drag them to car - free heat!

sadly enough even water, but better oil has better capacity then Lead-ACids


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## madderscience (Jun 28, 2008)

Some other nut job heating ideas:

1) Design your car so that waste heat from the controller can be pumped into the cabin. This could be as simple as mounting the controller on the firewall and a finned heat sink with fans on the other side, in the cabin. That will get you several hundred watts (not much, but something and free) of waste heat. You might want to design it so that you can move a louver or something to get exterior air onto the cooling fins during summer though.

2) Mount the charger such that waste heat can be circulated into the cabin. Will keep the cabin heated a bit while charging. My car is set up this way, and provides a bit of help.

3) Use a small catalytic propane heater if you need supplemental heat. yeah, it emits some carbon. life sucks.

4) Get some old heated seats from a junkyard car. Due to direct contact between you and the heated surface, fewer watts will be necessary to keep you comfortable

5) If you've got a setup that is capable of regen, dump some regen energy straight into a big ass resistor in the cabin instead of pack recharging. Here a fluid reservoir might be a good idea to buffer the heat energy a bit.


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## JRP3 (Mar 7, 2008)

madderscience said:


> Some other nut job heating ideas:


You said it 
1)Unless you are really driving near the limits of the controller most of the time you won't get anything worthwhile.
2)Same thing. My 30 amp PFC charger doesn't put out much heat at all.
3)That would work.
4)Or get some heated seat covers. I've got a heated massage pad that will run on 12 volts, I can drive and get a shiatsu 
5)Not worth it unless you are going down a loooong hill, and still probably not worth it.


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## Stunt Driver (May 14, 2009)

heated seat covers is a must - I come from cold country, they really work. Got one in my fiero too. 

As for controller - my setup is low power, and 72V alltrax is cold (not even warm) after my 2 ride to work. I guess for 144+ systems it's different, but with such cost of convertion - might as well use electric heat and bigger pack

Ideally, i'd like to find gasoline heater from cars like VW Bug or other with air-cooled engine.


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