Luxury items

Foxster

Section Hiker
I've kept an eye on these stove-to-power gizmos for a while and even had a go at making my own. They suffer from some fundamental problems...

1. They can't make much power despite the claims because they can't get a good heat differential needed to generate electricity. In practice this has meant some mobile devices not charging at all and some getting just a couple of % charge over an extended period.

2. Most of us boil water in three minutes. Some us might run a stove for, say, 10 minutes to cook some food. Neither of these is long enough to charge a device. This means repeated and extended boiling.

The dedicated device above looks the most promising but, as pointed out, it is heavy and uses a lot of gas. Perhaps useful when car camping, but then you could use the car battery anyway. Might be useful to some with a wood fire but it doesn't look rugged enough to go on a large enough wood fire.

They suffer from a fundamental problem of a great deal of energy being wasted in the conversion from gas to hot water to electricity. Of promise is the idea of a catalytic micro-combustion device that you feed with camping gas to generate electricity. These have the potential to be more efficient but I suspect they might be expensive and heavy.
 

Odd Man

Thru Hiker
I've kept an eye on these stove-to-power gizmos for a while and even had a go at making my own. They suffer from some fundamental problems...

1. They can't make much power despite the claims because they can't get a good heat differential needed to generate electricity. In practice this has meant some mobile devices not charging at all and some getting just a couple of % charge over an extended period.

2. Most of us boil water in three minutes. Some us might run a stove for, say, 10 minutes to cook some food. Neither of these is long enough to charge a device. This means repeated and extended boiling.

The dedicated device above looks the most promising but, as pointed out, it is heavy and uses a lot of gas. Perhaps useful when car camping, but then you could use the car battery anyway. Might be useful to some with a wood fire but it doesn't look rugged enough to go on a large enough wood fire.

They suffer from a fundamental problem of a great deal of energy being wasted in the conversion from gas to hot water to electricity. Of promise is the idea of a catalytic micro-combustion device that you feed with camping gas to generate electricity. These have the potential to be more efficient but I suspect they might be expensive and heavy.

How did yours turn out? Did you use one of these?


If one was to be able to use a bush box to generate electricity, then there would be no shortage of fuel. Just have a small fire going for a couple of hours each night.
 

Rog Tallbloke

Thru Hiker
Sure, and I've had plenty of entertainment playing around with TEGs over the years. The best application I found was using one to run a small fan to turbocharge a small woodstove. I water cooled the aluminium CPU cooler bonded to the cold side of the TEG with a breadbag full of water tied to the tent pole top and a small bore plastic tube. Still burned out the TEG eventually though...
 

Teepee

Thru Hiker
These little water turbines look promising for some trips if they can get the output up and the weight down. I've delved into them a few times for longer trips but they got discounted for the low output, high weight, and the fact an errant twig will jam the blades.


gkh_20191011-0019__1_600x600.jpg



https://shop.waterlilyturbine.com/products/waterlily-turbine?variant=29523372048445


There is a wind, drybag, and a hand crank attachment for them too.
 

Bopdude

Thru Hiker
I've looked at them as well @Teepee they are big though, also looking at the wind turbines, they look promising, a tad on the expensive side though, I'll find a link
 

Norrland

Ultralighter
Wind seems the obvious choice for future development considering most of us spend time high up in the windy hills. That fabric wind turbine is pretty nifty. Bet it makes a right racket though.
 

Odd Man

Thru Hiker
Wind seems the obvious choice for future development considering most of us spend time high up in the windy hills. That fabric wind turbine is pretty nifty. Bet it makes a right racket though.

I wonder if it's DCF, DCF being a sail fabric and all..
 

Bopdude

Thru Hiker
I was thinking just to play with one of those Micky mouse ones for less than a tenner off of Amazon just to see?
 

Rog Tallbloke

Thru Hiker
These little water turbines look promising for some trips if they can get the output up and the weight down. I've delved into them a few times for longer trips but they got discounted for the low output, high weight, and the fact an errant twig will jam the blades.
https://shop.waterlilyturbine.com/products/waterlily-turbine?variant=29523372048445
There is a wind, drybag, and a hand crank attachment for them too.

They're claiming this device will generate 5W - 15W (a 1-3A charging rate for your phone) in a 2-6knot flow (biggish river on a good slope), so that makes it useful for known locations only. Under a waterfall is probably your best bet in the UK.
The wind accessory makes around 5W in a 20mph wind
so I wouldn't tote that about.

As for getting the output up and weight down, it's a tough job. The laws of physics are what they are, and the weight of copper doesn't change as tech improves. I did try making a packable wind turbine with polycro sails, cf struts and the motor out of an inkjet printer. It made about the same amount of power for about the same 1.2 kg weight, but was fussy, fragile, noisy and needed goldilocks windspeeds around 30mph to do anything useful.
 

Rog Tallbloke

Thru Hiker
I've looked at them too but this is the one I'm on about.

Clever, but they don't seem keen on showing us how the top end of the rig is supported in that vid do they?!

Looks like it might be suspended from a sapling about 13 secs in. It'd need to be a lonely sapling though. I guess a trekking pole well lashed to a fence post might work but I bet vibration is an issue.
 
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cathyjc

Thru Hiker
I've no engineering knowledge and my physics is even less - BUT surely a mini turbine to drop in running water would harvest more reliable and usefull energy to create electricity ??
 

Rog Tallbloke

Thru Hiker
I've no engineering knowledge and my physics is even less - BUT surely a mini turbine to drop in running water would harvest more reliable and usefull energy to create electricity ??
Yes, that's what the water lily device @Teepee linked does. Clever stuff, but needs to be monitored frequently for grass binding up the rotor or sticks getting jammed etc. Has to be close enough to the river bank so the cabling isn't too long too.
 

Bopdude

Thru Hiker
The lightest thing I've used with any joy at the moment was my Mini0 peltier charger, used it in Sweden a few winters ago, of course you needed to keep a fire going of some sort but it worked well enough to light the tipi or trickle charger a battery pack. I might have to dig it out and play some more.
 

Rog Tallbloke

Thru Hiker
The TEGs available on the market fry at about 150C. At 100 degree temperature difference they give: open circuit voltage 4.8V, generated current: 669MA, but line losses etc reduce this value. You want at least 4 in an array to charge a phone at a decent rate. They weigh around an ounce each. You'll be using a twig stove for this and that's where things get tricky. Direct flame will melt the solder and fry the TEG, so you have to shield the hot side, and cool the cool side so you end up with around 100C difference across the plates. Controlling that with the variability of heat output from a twig fire isn't easy. There's not much margin for error.

My attempt involved using some of the power generated to run a fan which turbocharged the twig stove. The 'clever' bit was that the hotter the stove got, the more power was generated, and I used that signal to *reduce* the voltage going to the fan, so it slowed down and made the stove cool down. It was partially successful, but I ran out of TEGs and patience before I perfected it.
 
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Bopdude

Thru Hiker
I did see once a pack which charged as you walk, can't remember the how's and what not's, @Rog Tallbloke apart from the odd picture and call/text I rarely use the phone now, all I was saying is there are options available, if it's your thing, luxury item ;)
 

Rog Tallbloke

Thru Hiker
The pack worked with linear dynamos and springs and only worked on level paths where you could tailor your gait to the rythm of the packs motion, which varied with it's weight...

Then there was the Pentagon's 'heelstrike' piezo technology, with wires taped to the backs of your legs.

Endless fun that'll probably get you the latex glove treatment at the airport....
 

Rog Tallbloke

Thru Hiker
Of promise is the idea of a catalytic micro-combustion device that you feed with camping gas to generate electricity. These have the potential to be more efficient but I suspect they might be expensive and heavy.
I looked into this as a way of quietly powering an electric bike with more autonomy than a battery could offer.
I found a 380W unit running on propane which could just about be secreted in a small kiddy trailer. 14kg plus your gas cylinder.
£7 grand and needing expensive servicing every few hundred hours of use... 😧
 
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