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Discussion Starter · #1 · (Edited)
Let me have a patent on this, if it's a new idea:)

Idea is - fill gas tank with water (antifreeze), and have it heated up to 90C with thermostat control while plugged in. Tank would have to be insulated, so heat doesn't escape.
When driving - pump water thru heater core. Possibly can use existing fuel pump, or better something less noisy.

8 galons of hot water while cooling down from 95 to 45C will give out 1.6KWh of energy - that is 3 T-105 batteries of energy, and with 1KW of heat - will last over an hour ( which is more than my car's range).

If properly insulated - should be hot even after 5-8 hours parking at work. Drain it at summer for less weight to carry around.

the only downside - have to carry 60-80 pounds of weight with you, which is same as batteries of such energy capacity, but doens't cost a bit :)
In Fiero - gas tank is located in tunnel, which is hardly usable for anything else anyway.
 

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Discussion Starter · #3 · (Edited)
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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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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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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Discussion Starter · #6 ·
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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Discussion Starter · #7 · (Edited)
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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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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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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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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Anyone tried a heat pump in combination with the 'hot' water output of a water cooled motor and/or controller?
 

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Discussion Starter · #16 · (Edited)
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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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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Discussion Starter · #19 ·
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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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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