airbreather 7 days ago

If you go to here and plug in some numbers

You see that at around 0.2m blade length a HAWT will generate 40W at 28 mph wind. 28 mph is "Strong Breeze", according to the National Weather Service and in which you probably really don't want to be camping.

Strong Breeze = "Large branches in continuous motion. Whistling sounds heard in overhead or nearby power and telephone lines. Umbrellas used with difficulty."

But when you get down to 15 mph (moderate breeze) it's only making 6 watts, and at 8mph (gentle breeze) it's making 1 watt.

That is assuming steady wind to think you will get that continuously, derate accordingly.

I suspect there will be some gap between expected and actual performance for many people.

  • mrtksn 6 days ago

    Still, it can be useful since certain places reliably get strong winds. Think of all the sports that rely on windy conditions, then consider that those sports are conducted far away from the grid. That's your target market.

  • skykooler 7 days ago

    The best use-case I can think of is when hiking to the top of a mountain or large hill, where the top will be exposed and have much higher windspeeds than might be found in the camp site you came from.

    • dzhiurgis 7 days ago

      Maybe a hut should have one of these

      • clort 7 days ago

        Well yeah, but a hut could have something a bit more robust, with a larger battery bank. This is optimised for weight, which a fixed installation does not need to be.

  • kyriakos 7 days ago

    Wouldn't solar make more sense? And they are already on the market today.

    • svantana 6 days ago

      Thin film photovoltaic is definitely better on a watts-per-kg basis, but it's no good for the charge-while-you-sleep use case.

      • donjoe 6 days ago

        Also, most portable devices on the market won't provide you with enough power for charging electronic devices in cloudy conditions.

        My ideal combination to cover about 80-90% of power needs whilst camping/hiking/cycling would be a combination of water turbine (for rivers or tiny streams) and solar.

        In case I'd be hiking in an area with no water supply, I'd consider something like a wind turbine. Yet, I wouldn't know why I would want to hike in an area with no water supply ;-)

        • causality0 6 days ago

          I'm surprised they don't sell some kind of reciprocating dynamo-type thing for hikers to strap to their knee to charge while walking.

          • shard 6 days ago

            Doesn't that just increase resistance to your walking, thus is equivalent to you converting calories to battery energy? Wind and solar would be additional energy over what you brought as stored calories or food.

            • rowanajmarshall 6 days ago

              Going by a random Reddit thread [1], it takes less than 5 calories to charge an iPhone. I think that kind of device is already on the market though.

              You're not gonna power a heater or aircon through body movement, but devices should be fine.


              • Dylan16807 6 days ago

                It's just a unit conversion, you don't need to cite reddit.

                A Calorie is slightly more than a watt hour.

      • megablast 6 days ago

        But wind usually drops at night.

      • is_true 6 days ago

        That's why taking a nap is important

      • dtgriscom 6 days ago

        Unless you hike the night shift...

  • Someone 7 days ago

    It also is only about a meter or so up from the ground. You rarely get a strong breeze there even if there is a strong breeze blowing.

    • pmontra 6 days ago

      This is correct but if you use it at home you can place it on the roof or on a terrace or stick it to a pole. I didn't research the subject, maybe there are better turbines for that use case.

      • Someone 6 days ago

        “On a roof” may not matter much if neighboring houses are as high as yours. You want to be higher than anything close by.

        If you’re going to use a longer pole, portability goes out of the window, as the pole will have to be stronger, too.

        Then, you might as well get an even stronger longer pole and increase the turbine diameter. Micro wind turbines rarely make sense.

  • jrootabega 6 days ago

    It's great at generating clicks-per-blogpost though.

  • gorgoiler 7 days ago

    Wouldn’t you leave it at camp (or a prominence next to your camp) and have it constantly trickle charging a battery?

    It would be charging itself all day and all night at a couple of Watts. Then when you come back to camp you speed charge your phone at a full 50W.

  • Fargoan 6 days ago

    I live in North Dakota. I think practically everyday is moderate to strong breeze here.

UI_at_80x24 7 days ago

40w max output @ 28 miles/hour windspeed.

12,000 mAh internal battery

There's no mention of voltage but it looks like it uses USB connectors, so let's assume 5v. This turbine running at full-load (with NO losses)

40w @ 5V = 8A (maximum theoretical)

8A * 1.5hrs = 12,000mAh (1.5hrs minimum theoretical time needed for a full charge.

Now divide everything by 1/3rd for better 'real-world' (aka pessimistic) numbers.

13w average output

13w / 5v = 2.6A

2.6A * 4.5hrs = 11,700mAh

So really not that bad, but most of the time I'm camping the trees block 95% of the wind. On the other hand that other 5% does seem to happen more then 5% of the time. =)

Here's the fundraiser site where it gives more details:

  • rhn_mk1 7 days ago

    > 40w @ 5V = 8A

    > 8A * 1.5hrs = 12,000mAh

    This assumes the battery is 5V, but lithium-ion batteries are typically counted as 3.6V.

    40W / 3.6V = 11.(1) A

    12000mAh / 11.(1)A = 1.08h

    Adjust the rest of the calculations accordingly.

    • naikrovek 7 days ago

      3.7v but they charge to 4.2v, but it doesn't matter, because the dynamo is going to produce variable voltages and currents. so it's going to go through a boost-buck converter and that will output 4.2v at whatever current it can.

      • rhn_mk1 7 days ago

        The peak voltage of the battery might be 4.2V, but the average will be around 3.6 nevertheless.

        The voltage before the energy enters the battery doesn't change the calculation of battery capacity (and its time to discharge) anyway.

        EDIT: now I noticed that the calculation is about charging, rather than discharging. 4.2V makes better sense in that case.

  • snares 7 days ago

    Would love someone experienced with wind turbines to chime in. Generating 2.4A at 5v from "hardly any wind" (8mp/h) would put this in another league to similar consumer options. Any guesses to their "patent-pending" technology?

    • UI_at_80x24 7 days ago

      I never said that you'd get 2.4A @ 8mph wind. I just dropped all the other numbers by 1/3rd. I have no idea how fast the wind has to blow to get that level of power output.

      I would be willing to bet that 8mph wind only gives you ~500mA of power (which is what USB v1.1 operates on), and that fancy internal battery is probably using off-the-shelf circuits so that you can charge phones.

      This product sells* for $400+ CAD. You can buy several 10,000mAh battery packs for that amount of money, and probably have a lot of juice left over at the end of your camping trip. [Note: I just did some searching and an Anker 20,000mAh powerbank can be bought for $33. So I could buy 10 of them for less cost and probably not need to charge them for a couple of months.]

      I'm kinda/sorta intrigued. The fundraiser page looks scammy IMHO, and is full of marketing fluff. I go bike-camping. Something like looks less practical then a 100w solar panel, but also more compact. Full sunlight is rare when/where I camp, I'm usually under tree-cover. That makes the solar panel weep, and is practically useless. I have to make compromises to make use of it. (i.e. the edge of a farmers field)

      This turbine might require different compromises, but the best thing it has going for it; time. I could leave it operating for 2 days giving me 48hrs of charging time, compared to the 3hrs of direct-overhead sunlight I might get while camping. That's 16x the amount of time for 'energy generation'. Even at less then my 1/3rd rate of power, that might charge all of my battery banks.

      I will wait for them to be built, and field tested by others. I'm not in a rush.

      *Not shipping yet, but we promise soon! /sarcasm

      • rascul 7 days ago

        > I go bike-camping.

        I wonder if the turbine could be attached to the bike in a manner that would generate electricity while you ride.

        • 0_____0 7 days ago

          the usual way of generating power on a bike is a front wheel generator hub. consider that a fairly fit cyclist can out 150 to 200 watts continuously. you might not notice 5W missing but you will certainly notice 20W. the 40W rating of this turbine is fully 1/5th of a fit cyclist's continuous power rating.

          • rascul 6 days ago

            Oops I wasn't clear. I meant attach it in a way so that the turbine would catch the air as you ride. Not sure how practical it would be.

            • 0_____0 5 days ago

              either way the energy comes from the rider.

        • UI_at_80x24 7 days ago

          The drag it would induce would make it intolerable.

      • tlb 7 days ago

        Power of a wind turbine is proportional to the cube of windspeed. So if 28 mph gets you 40 W, 19.4 mph gets you 13 W.

    • na85 7 days ago

      >Any guesses to their "patent-pending" technology?

      I'd wager it's the airfoil and/or the blade construction.

  • bryanrasmussen 7 days ago

    so since I have a membership at this place and they have a bunch of ultra fast wind experiences I could go there, set this up, and work on my projects in the cafe!

    Sure, I could also just plug in to their el, but where's the cool in that?

    • lordnacho 7 days ago

      That place is awesome btw, well worth a visit for anyone, especially with kids.

Stevvo 7 days ago

I have a 400W wind turbine along with 400W of solar on my boat. The turbine almost never gets used as it makes more noise than a 1500W gasoline generator.

  • mikro2nd 6 days ago

    +1 - I came here to ask about the noise emitted by this "water boittle" turbine.

    A local neighbour has 4 small turbines (the kind typically used on boats) mounted atop 14m masts, and they make a hell of a racket when the wind is strong enough to make them generate reasonable (read: rated) amounts of power (which is pretty seldom around here.)

    Frankly I doubt whether this machine is nett energy win over its lifespan. To me it looks more like a virtue-signalling device than something seriously meant to generate energy.

jimmySixDOF 7 days ago

As for non typical wind systems, I was looking recently at some vertical axis wind turbines after seeing some flower/tulip designs and for anyone interested this Tesup Atlas 4 model seems to be as good as it gets [1]. Starts generating at 10mph and gets to 4kw at 35mph. Its about a 4ft square footprint and 50lbs so not in the same class as TFA but then again this will do more than trickle charge a cell phone.


  • nabla9 7 days ago

    What really concerns me about that Tesup model is 3-blade design with small air gap between blades. I have no idea how they think that would be more effective than 2-blade Savonius-principle rotor.

    It's possible to sell consumers ad-hoc designs that are unnecessarily inefficient just because they look cool.

samatman 6 days ago

Something vaguely like this might be quite nice if the designers thought in terms of sails rather than propellers.

Using the existing principles of tensegrity applied to self-supporting tents, this could have enough surface area to run the generator at maximum in a gentle breeze, with some possibility of trimming in actual wind.

It would be a completely different product but it's not an implausible one.

Edit: I'm thinking vertically mounted with three 'jib' sails which are constrained on (let's say) the clockwise side, these would take turns catching the wind, then relax into the leeward and snap over onto the bar when returning to windward.

vatotemking 6 days ago

A 10watt solar panel and a step-down module that can charge a powerbank is the simplest, cheapest, most portable option I can think of.

airbreather 7 days ago

I normally camp near running water, a more practical idea in this case would be a small water turbine, especially as water water enables smaller size for same power and generally constant flow so power output needed is less than generally intermittent wind.

The other thing is it doesn't say how noisy it is - bet you it's pretty annoying if it is making 40W, probably even at 15-20W.

  • UI_at_80x24 7 days ago

    They actually do mention the noise, 50dB max. That is equivalent to a "quiet conversation in a house".

    BUT in a secluded camping spot, I'd bet it's quiet noticeable. (Compare a quiet conversation in a house to a quiet conversation in a library.)

    If you normally camp near running water, you are more accustomed noise and might not even notice it. I once camped near a small stream, just wide enough that you could jump across it; it was shallow, and had a very calm 'babbling brook' sound during the day. Wonderful and calming. By bedtime this peaceful flow was an utter torment, and much too loud.

oftenwrong 6 days ago

3 pounds = 1.36kg

It's heavy for most recreational activities, but it might be great for expeditions. If it could be made very durable, it could be beneficial for superdeep cave exploration. In such environments there is no light, but often there is rushing wind and water. There is also a critical need for power to keep lights running. While charged batteries can also be brought in from the surface, they have a limited lifespan in the cave, and an expedition therefore needs a continuous supply of fresh batteries to continue.

TrispusAttucks 7 days ago

How does this compare to a micro solar panel?

  • pg_bot 7 days ago

    The economics don't make sense to me. You can get a solar panel and portable power station for less cost today for similar or better power output. The only benefit here is that this will work in the dark, but even then I'd rather just put more money into battery storage. Combine that with the fact that this is a kickstarter and not a product sitting on store shelves, and that small wind turbines generally don't make much sense due to the laws of physics with regard to efficient power production. Hard pass.

  • maxerickson 7 days ago

    I guess you would often get closer to the true output of the 20+W solar panels, at least during summer daytime.

    I haven't done extended hiking or similar, but I expect "phone off" (and maybe a usb battery) is pretty competitive as a solution, with charging when it happens to be available.

    • conk 7 days ago

      I’ve done a lot of backpacking and tried various approaches inluding solar panels but I’ve settled on bringing a good 10,000mah rechargeable usb battery pack. With this I can keep my garmen inreach mini, iPhone and headlamp charged for 5-6 days on the trail with a battery that weighs 6oz.

  • im3w1l 7 days ago

    It's nicer to hike on a sunny day than a windy day.

adrianN 7 days ago

It probably makes more sense to carry three pounds of batteries. Small wind turbines that are close to the ground hardly produce any power. Or two pounds of batteries and a small solar panel.

  • gorgoiler 7 days ago

    I seem to recall off the shelf turbines are available that you erect and guy, on long whip fishing pole like devices, to get them a few feet higher up.

ck2 7 days ago

Aren't there physics tricks that could be used like Bernoulli and Venturi effects for a reverse mini dyson-fan as generator?

  • ghostly_s 7 days ago

    You are aware a Dyson fan is just a conventional fan with a futuristic-looking duct attached?

hadlock 7 days ago

"will provide power at wind speeds from 8 to 28 miles per hour"

Neat idea but unless you are within 3 miles of the coast you're unlikely to see wind speeds above 6mph in your area for any sustained period of time.

  • MetallicCloud 7 days ago

    Really? I'm in Boulder, CO and we often have days of continuous strong winds. We're nowhere near a coast.

    • micromacrofoot 7 days ago

      yeah because you're way up a mountain!

      • oh_sigh 7 days ago

        Another boulderite checking in... Boulder is right on the foothills and mostly on the plains, not the can just get to a mountain within 10 minutes.

        • tejtm 7 days ago

          sea level checking in, err Boulder you are nigh a mile high. It would take more than 10 minutes to fly off the mountain you are already on.

          • oh_sigh 7 days ago

            So you consider Kansas a mountain then? Interesting...

        • morcheeba 7 days ago

          Let's test it at the NREL National Wind Technology Center!

      • gorgoiler 7 days ago

        North Dakota has entered the chat.

        Windiness, as you say, is indeed correlated with exposure. The top three ways of exposing oneself are: ocean (or the next best thing for land lubbers: coast next to ocean), mountain, and wide open space.

  • regularfry 6 days ago

    In Olympic recurve archery, as a rough rule of thumb I found that wind speeds were very easy to compensate for when they were in the single digits, hard when less than 20mph, and virtually impossible higher than that.

    I live about 100 miles from the coast, and the number of days I can remember having an easy time of it is of the order of five in a given year.

  • seizethegdgap 7 days ago

    Wyoming, the Dakotas, Montana, Colorado, Iowa, Minnesota, and Texas say "Hi".

    • hadlock 3 days ago

      Ok you buy the thing and see if it's practical for your lifestyle and let me know how that goes for you. At no point in the last 30 years did we not have the technology to build this device, nor is it a novel concept. Look around and see how popular they are, and wonder why.

  • spaetzleesser 7 days ago

    Come to Albuquerque and you’ll see a lot of wind.