Radio Preppers

General Category => Technical Corner => Topic started by: piggybankcowboy on September 30, 2012, 03:01:37 PM

Title: The Power Pot
Post by: piggybankcowboy on September 30, 2012, 03:01:37 PM
Have any of you seen these yet? https://www.thepowerpot.com/ (https://www.thepowerpot.com/)

The $150 price point seems a bit harsh, but I'm not familiar enough with the materials used to make them to know if it's worth it or not.

What do you guys think? How difficult would it be to make your own?
Title: Re: The Power Pot
Post by: gil on September 30, 2012, 03:25:37 PM
You can't get much from a thermopile... Sure, they work, but 15W? I doubt it... I could be wrong though... A solar panel might serve you better, for the same price.

Gil.
Title: Re: The Power Pot
Post by: piggybankcowboy on September 30, 2012, 04:36:48 PM
Perhaps, yeah. The claim I saw was up to 5w generated, but I may have misread or misheard that.

What's kinda selling me is the fact that it's also a pot, which is handy to have in a kit for wilderness survival, if it comes to that, so I guess you could use it to make some food if you need to. Multipurpose tools always get my vote. Problem would be, in that type of scenario, a lot of factors play in to whether or not you can successfully get a fire going in the first place.
Title: Re: The Power Pot
Post by: Mitch on October 01, 2012, 09:24:58 AM
I have zero experience with this pot, but many years of experience using thermocouples as an instrumentation expert.

You will see exotic forms of corrosion between any 2 dissimilar metals (this is how they are creating voltage). Without something like a sacrificial anode your individual junctions that create the electricity will become electrical opens or high resistance in a fairly short time. I can also say from experience that the more current you generate from each junction the faster this phenomenon happens.

I can't imagine the fuel residues from cooking helps this matter any either.

All metals have different thermal expansion coefficients also... Cooking can rapidly change the temperature every time you use it causing the metals to buckle and lose contact (electrical open again).

I expect you would get useable power (although 10W isn't great) for a while, but rapidly loose capacity.

I also may be way off course with my thinking- but I wouldn't buy that contraption for power generation especially at that outrageous cost.

It takes much longer for solar panels to break down and the "fuel" is easier to come by in a SHTF scenario.
Title: Re: The Power Pot
Post by: Mitch on October 01, 2012, 09:34:16 AM
I was just thinking a little bit more about the power pot.

I don't like the power pot idea much, but if someone has a spare RTG lying around- that would be useful in a SHTF scenario!

;D

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator (http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator)
Title: Re: The Power Pot
Post by: cockpitbob on October 01, 2012, 11:04:25 AM
I design cooling systems using thermoelectric coolers.  The PowerPot is just using a cooler backwards, and it should work just fine.  My only concern would be the life expectancy of the cooler.  On one side it will have 100degC (boiling water) and the other side will be even hotter.  I don't like to get them hotter than 80degC, but I'm not using the ones design for high temperature work like the PowerPot must have.  I would say it looks OK. Just don't boil it dry.  And don't drop it since most of the thermoelectric coolers are made on a cereamic base that is very brittle.

For the next Field Day I plan on putting one together powered by a candle.  What makes thermoelectric generators work is a temperature difference, so on the cool side I'll have a CPU heatsink with small fan, and I need to make sure the candle is far enough away to not overheat the hot side.  I expect to get at least 5-10W out of it which will be more than enough to keep up with my little MFJ-9420 which draws 0.1A listening and 1.5A transmitting 10W.

ETA:  Someone is making a backpacking size wood stove with a thermoelectric generator in it.
http://biolitestove.com/
Title: Re: The Power Pot
Post by: Mitch on October 01, 2012, 11:32:46 AM
At about 80W "ideal" energy capture from a single wick candle that will be an astounding transfer efficiency rating.

If you can do it color me impressed!

Pictures please- inquiring minds want to know (and burn their fingers trying it too)!

;D


Every time I think about how you are going to do it I envision at least 4 steps that are only about 20% efficient.

Title: Re: The Power Pot
Post by: Mitch on October 01, 2012, 11:39:34 AM
For what the power pot does you might also be interested in http://www.npowerpeg.com (http://www.npowerpeg.com).

Of course if you don't shake your leg up and down as much as I do, you won't be able to power your Iphone!

At least you get the integrated 2000mAh storage included in the price...