Crazy idea ... anybody know if it works??
http://www.backcountrygear.com/catal...il.cfm/POE1065
I see using it for moto camping and plugging it into the bike's main battery.
Crazy idea ... anybody know if it works??
http://www.backcountrygear.com/catal...il.cfm/POE1065
I see using it for moto camping and plugging it into the bike's main battery.
Would probably work, but I think you would probably be better suited w/a UQ. Consider travlin on a bike, proximity you can park to trees, flexability of system. JIMO
" Wiggs "
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Interesting...a bit heavy...I didn't see that 12v powers it...for that matter...what powers it...batteries???..even more weight...unless you're carrying it in the back of your truck...but something in extreme cold that's generating a heat source would be niiiiicce !!
http://www.trailspace.com/gear/pacif...ulmat-hot-pad/
One review says 4AA, one says 6AA. Auto temperature controlled thermostat.
To Boldly Hang Where No One Has Hung Before...
4 or 6 aa batteries is still not bad to alleviate C.B.S.
6 Lithium AA batteries weigh about 3oz. If it truly lasted 8 hours (doubt it) why is this not selling like the next apple I gizmo?
good question .. I might pull he trigger just to try it out.
If we assume 6 AA lets do a thought experiment.
Lets assume the numbers here are correct:
http://www.allaboutbatteries.com/Energy-tables.html
The best-of-class battery holds 9360 joules of energy. * 6 is ~56K joules or 56K Watt-Seconds. Divide that by 60 and then 60 again to get watt hours, which is about 15.5 Watt-Hours. So, you can get 15.5 Watts of heat out of this for about an hour, 31 watts for 1/2 hour... Lets assume you want to sleep for say 6 hours and lets assume it is setup to dribble out the heat over this amount of time. That means its only putting out 15.5 / 6 or a bit over 2.5 watts of heat continuously over this period of time (not so good).
Considering a body at rest puts out somewhere around 100 Watts at rest this means a 2.5% increase in heating capability over these 6 hours. This is pretty insignificant as a small amount of insulation can help conserve much more than this!
For comparison:
A BTU (British thermal unit) is characterized as the amount of energy it takes to raise the temperature of 1 pound of water 1 degree F. It equals about 1050 joules. With these numbers in mind and a little math we can figure out how much hot water it would take to equal the heating capability of the above system which we said stors 56K joules.
56000 / 1050 = ~53 BTU.
Now lets assume your "hot water" is still helping you out as long as it is warmer than you are - so lets just say anything over 100F. Lets also assume we're not going to heat it to a boil, just to 200F (a convenient 100F delta). So we would need to heat 1 pound of water 53deg F above 100F (153F) to get the same energy... or about 0.53 pounds of water heated to 200F. So how much water is that? Welp water weighs about 8.3 pounds per gallon so we're talking about 0.53 / 8.3 or 0.063 gallons of water OR almost exactly 8 ounces of water.
(YES - 8 lousy ounces).
So...
That means, to get the same heating (if my math isn't entirely off) all you need to do is heat 8 ounces of water to near boiling, seal it in a good container and then in a sock for "slow release" and viola! You have the same amount of heating this system can produce. Double the amount of water and you've doubled the amount of heat it can put out.
It should be noted I sleep with 32 ounces of hot water and find it "adequate" for keeping my tootsies warm on those super snotty days. With that said, I would likely find this system approximately "1/4 adequate" - which is 3/4 shy of adequate
Neat idea, but battery technology just isn't there yet.
[stuffy math rant over]
X
[EDIT: Somebody check my maths - been drinking taddy porter so who knows!! I know I dropped some decimal points but this isn't meant to be super accurate just really close lol]
Last edited by Pitch; 01-22-2011 at 22:17.
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