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groingo
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# Posted: 11 Jan 2015 01:49am - Edited by: groingo
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A week has now passed and monster 45 watt generator has run everything with power to spare, (my power requirement is 15 watts max full load)...the solar was not used for cabin power but to keep the batteries charged which are now relegated to backup duty, last week was 100% TEC powered.
The generator runs off excess heat from the propane stove then into the inverter for appliances and can be generating power in about 30 seconds from time stove is lit.
Next week I splurge and order the big TEC at 92 watts to provide a bit more cushion at an astronomical price of $5.49 including
shipping!
What began as tinkering quickly moved to a viable low cost energy source and yes, it also works well on the wood stove since it is just an upgraded Ecofan!
It's cheap, fun and uber rewarding, everyone living off grid should try it as the possibilities seem endless!
The ultimate goal in my case is to eliminate the need for batteries all together.
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Steve_S
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# Posted: 11 Jan 2015 03:19am
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OK, a tad short on details here groingo... Please elaborate will ya ? What ya up to there ?
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groingo
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# Posted: 11 Jan 2015 11:01am
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Still working it out myself, the key thing to remember about these things is the power ratings on them are for use as a cooler so for example 12 volt at 45 watts is the power they would draw to cool a device, power generation is a lot less so you need to use them in blocks or series.
In the case of my 45 I actually use four TEC's to create the voltage and amperage I need, unfortunately the cheap Ebay and Amazon TEC's are just that and with the slightest overheating cook themselves, but they are good for establishing the next steps and learning from....beats watching tv lately anyhow!
There is lots of information on these generators on Youtube, by just looking for thermo electric power generators.
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MtnDon
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# Posted: 11 Jan 2015 11:15am - Edited by: MtnDon
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I believe some of us have no idea what you are doing. I have some idea. Maybe I missed some earlier post.
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Steve_S
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# Posted: 11 Jan 2015 11:43am
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I suspect that Groingo is tinkering with thermo-electric Seebeck Effect device power generation...
The Peltier method would be suitable for a cooling application like a fridge / cooler...
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creeky
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# Posted: 11 Jan 2015 12:13pm
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thermo electric power generation. which board do you have? pictures?
I would like to see the output on a voltmeter as I had thought that the output was in the milliamp range. I guess that's improved with ecofans and biolites using the teg tech.
So, in the winter the propane stove heats the room and generates a little electricity?
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razmichael
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# Posted: 11 Jan 2015 01:25pm
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TECs are not efficient (hence the thermo electric coolers are not really useful for any off-grid cooling), but when using in reverse (heat to electricity), the lack of efficiency is not really an issue (free heat - free power). Sounds like Groingo is doing this DIY (and I bet having fun). I know of one manufacturer (might be more) that produces the modules for this
DevilWatt
with a distributor through
tegmart
No experience with them, just did some research on them a while back when I was thinking of using a wood stove. They are not cheap but can provide a steady load when you may need it most - winter with the stove going all the time.
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groingo
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# Posted: 11 Jan 2015 01:33pm
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Raz:
I originally grabbed a handful locally and started farting around but soon found that they can be very effective when used in groups, big thing is controlled heat.
My source now for information and product is: http://tecteg.com/thermoelectric-power-module-selection-purchase/
In my use (15 watts) these are usable but for greater power needs
it could get very pricey.
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Wilbour
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# Posted: 11 Jan 2015 09:27pm
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The lamp i bought uses this technology to turn one tea light candle into the power of 18. Not cheap though.
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groingo
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# Posted: 12 Jan 2015 11:51am
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Just got off the line with Tegpro who make the DevilWatt generator and they do make a 35 and 75 watt water cooled power brick but there is an issue, there's seem to be based on use in 24 hours so they would produce 35 watts over 24 hours 35 watts constantly.
Currently cheap TEC's are not lasting, about a week before something craps out but that was expected....but he did mention he has been using some Lithium and Ni Cad batteries with some off grid success so will wait for his information on them.
My main goal is to either eliminate the batteries or find something better to replace them with which is why I am looking at all alternatives.
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razmichael
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# Posted: 12 Jan 2015 02:45pm
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Quoting: groingo Just got off the line with Tegpro who make the DevilWatt generator and they do make a 35 and 75 watt water cooled power brick but there is an issue, there's seem to be based on use in 24 hours so they would produce 35 watts over 24 hours 35 watts constantly
Are you sure? Specs are max 18 volts at 4 amps for 72 watts - i'm fairly sure that is continuous BUT at the maximum temperature differential. These figures are based on a very hot stove (518F). I seem to recall they used to have a better spec sheet that covered the output at various temperature differences and the output dropped quickly as the difference between the hot and cold plate reduced This may have been with a different product but I think you will find the results similar as it the nature of the technology. This is why I mentioned that these are not really efficient but could augment your power and battery charging during the times the stove is running. No way I would see them to replace batteries - too many variables. Another factor is the high cost - at $600 for the 70 watt module - you could put up a couple of extra panels to make the most of the daylight.
Suggest you try to get a better spec sheet to see what more real life use would give you at various temperature differences.
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razmichael
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# Posted: 13 Jan 2015 12:20pm
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Groingo
Not sure it adds much but I though this had come up earlier ...Feb 2014
Anyone ever tinker with this idea? peltier module
I did see that the specs for the non-water cooled versions of the DevilWatt has graphs to show the output at various stove surface temperatures. Note that the maximum output requires a stove temp of around 800F which I think is a fairly hot stove.
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MtnDon
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# Posted: 13 Jan 2015 01:51pm
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Quoting: razmichael stove temp of around 800F which I think is a fairly hot stove
That's an understatement if there ever was one. 
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groingo
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# Posted: 14 Jan 2015 11:31am - Edited by: groingo
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When used on a wood stove is where the problem with getting the heat high enough without cooking yourself out of the place, that is also why I only use them on a propane flame, easy to regulate and easy to reach best operating temps without cooking yourself out.
Thus far the best operating temps for longest life in the 300 to 450 heat ranges otherwise they cook.
There are claimed higher quality chips but the jump in price dramatically fro 22 to over 70 dollars a chip....and that's where I draw the line...quickly moves from fun to stupid.
The manufactured ( TEC Generators) I have seen have turned out to be much less than claimed especially for the prices they are asking, so for now will keep tinkering and maybe I'll stumble across something....it would really be nice to remove batteries from the equation.
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