Author Topic: Hand crank generator  (Read 6096 times)

Offline YoungGunsPrepper

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Hand crank generator
« on: March 19, 2012, 10:00:40 AM »
I found a hand crank generator, and I am wondering if anyone uses them or has any knowledge about them. I am considereing purchasing one but I would like some other people's oppinions on them or knowledge of what they know about them.

This is the one I am looking at.
http://www.safeandreadylife.com/pages/Home/itemdetail/394/

Offline Roundabouts

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Re: Hand crank generator
« Reply #1 on: March 19, 2012, 11:22:56 AM »
Don't know about them but sure looks nifty.  Hook it up to a bike or tread mill get your power while you are getting your work out  :)

Offline VeggieDog

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Re: Hand crank generator
« Reply #2 on: March 19, 2012, 12:12:35 PM »
Why did the Gilligan's Island theme song suddenly pop into my head?

Offline YoungGunsPrepper

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Re: Hand crank generator
« Reply #3 on: March 19, 2012, 12:30:29 PM »
Well I was orignially looking at doing a solar generator, but it was only 55W and well the downside is only works during the day, and it was going to cost around 300 after all was said and done. This being 250W and costing only 100 more I think I have made up my mind to go with this. After a little saving and when I purchase it I will post a review on how it works.

Offline Oregonprepper

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Re: Hand crank generator
« Reply #4 on: March 19, 2012, 04:57:19 PM »
Actually that seems pretty awesome.  That would make a killer bunker generator where sunlight wouldn't penetrate (for solar).

Offline Truik

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Re: Hand crank generator
« Reply #5 on: March 19, 2012, 08:26:49 PM »
Pretty neat concept and, with a little time and effort, easily replicable.

This device contains a permanent magnet alternator, a 12-volt battery, an inverter, a case and a couple pulley wheels, in addition to a few other small pieces and fasteners.

If you consider the cost of the purchase plus the cost of shipping such a device (think of the weight of the alternator and battery alone)...

and then consider acquiring the components separately from local suppliers and assembling it yourself.

I don't think there is anything wrong with the device itself. I would like to know how many RPM's of the large crank wheel are required to achieve the 250 watts it advertises.

If you were willing to spend the same amount of money you would spend to have that device delivered...and use it to build your own, you could probably come up with a permanent magnet alternator capable of producing two or three times as much energy.

Just my two cents.


Offline mxitman

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Re: Hand crank generator
« Reply #6 on: March 23, 2012, 12:47:27 PM »
Ya you can build one yourself if your a little handy. I was planning on building something like but build it into a hand cart so it's easier to move...I was going to make mine able to run off of small creek or river by using a paddle wheel or by hand/pedal/wind...could have used aluminum sheaves/pulleys to save weight too.

Look on ebay for Permanent Magnet (PM) alternators

Offline will3117

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Re: Hand crank generator
« Reply #7 on: March 26, 2012, 02:41:50 PM »
seems like it would be fairly easy to hook it up to a windmill, I cant see the hand cranked output on this being worth much.

nkawtg

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Re: Hand crank generator
« Reply #8 on: March 26, 2012, 03:33:39 PM »
The question is, how long do you need to hand crank to charge a 12v battery.

Offline Truik

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Re: Hand crank generator
« Reply #9 on: March 26, 2012, 04:16:14 PM »
seems like it would be fairly easy to hook it up to a windmill, I cant see the hand cranked output on this being worth much.

If you're looking for portability, or if you are located in an area with poor wind coverage, such a device could be very useful.

I'm always pushing for solar panels to generate remote energy but, frankly, if you needed more juice than what was in the battery and it was 11:00 at night, this might be the answer.


Offline will3117

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Re: Hand crank generator
« Reply #10 on: March 26, 2012, 05:22:54 PM »
true I can see it as a stop gap type thing,  but seems like a pretty steep price for something your not going to use much.  I think your looking at 400 for the unit and probably another 100 or so for shipping.  I guess as asked before the question is how many rpms need to be maintained for how long to charge a 12 volt battery?

Offline Truik

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Re: Hand crank generator
« Reply #11 on: March 26, 2012, 06:15:08 PM »
true I can see it as a stop gap type thing,  but seems like a pretty steep price for something your not going to use much.  I think your looking at 400 for the unit and probably another 100 or so for shipping.  I guess as asked before the question is how many rpms need to be maintained for how long to charge a 12 volt battery?

In the second video, you can see the hand wheel being turned 29 times between time frames 1:50 and 2:10 (twenty seconds) while the volt meter maintained an excess of 12 volts (averaging about 13 or 14 volts as best I can tell) so this would give us about 90 r.p.m. (29x3=87)

One thing that concerns me is the website says up to 250 watts continuous power while the device in the 2nd video says up to 70 watts. I only see one device and one price on the "buy now" portion of the page, so...unless I missed something: buyer beware.

This is one more reason I suggest making one yourself from components.


Offline will3117

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Re: Hand crank generator
« Reply #12 on: March 26, 2012, 08:46:23 PM »
In the second video, you can see the hand wheel being turned 29 times between time frames 1:50 and 2:10 (twenty seconds) while the volt meter maintained an excess of 12 volts (averaging about 13 or 14 volts as best I can tell) so this would give us about 90 r.p.m. (29x3=87)

One thing that concerns me is the website says up to 250 watts continuous power while the device in the 2nd video says up to 70 watts. I only see one device and one price on the "buy now" portion of the page, so...unless I missed something: buyer beware.

This is one more reason I suggest making one yourself from components.

I totally agree one would think that a great sales pitch would be to explain the pay-off i.e. 15 minutes of cranking equals this amount of power, the fact that they do not feel the need to include performance information is probably a very telling thing.  I would contact this vendor and ask about this type of information and before I ordered the generator,  I would ask them to send it in email or snail mail form.

Offline Jeff NH

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Re: Hand crank generator
« Reply #13 on: March 27, 2012, 05:01:03 AM »
In the second video, you can see the hand wheel being turned 29 times between time frames 1:50 and 2:10 (twenty seconds) while the volt meter maintained an excess of 12 volts (averaging about 13 or 14 volts as best I can tell) so this would give us about 90 r.p.m. (29x3=87)

Showing the volts is pretty meaningless as almost anything can generate 12 volts - While I think it would be cool to have a generator for fun and a little spare power, I suspect most people will be disappointed with the results. I am in pretty good shape (by no means a real athlete) but in any case I run a half marathon distance every weekend generally in 2 hours and I also bike every day. There is a bike at the gym that allows you to measure your output power in several units and one is watts. I can certainly generate 100-200 watts essentially continuously for 30 minutes but this is not a leisurely pedal speed but me trying to do intervals and sustain near max heart rate.

The gym bike is not actually generating power and dealing with various losses - it is simply measuring your theoretical maximum output power.

Still, I'd pay good money for an actual high quality bike based system if it were designed for a comfortable workout and could actually harness 100-200 watts that the gym bike indicates. It would be partially a gimmick (I'd probably connect it to a grid tie inverter so I could feel like I was sticking it to the man during a workout) and one could certainly charge small batteries with it. But, I'd only ever see this as a neat toy and not as a primary place to invest limited resources.

Offline Truik

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Re: Hand crank generator
« Reply #14 on: March 27, 2012, 05:08:06 AM »
Showing the volts is pretty meaningless as almost anything can generate 12 volts - While I think it would be cool to have a generator for fun and a little spare power, I suspect most people will be disappointed with the results.

I didn't say it was impressive, I was simply trying to answer the question.  ::)

There is a bike at the gym that allows you to measure your output power in several units and one is watts. I can certainly generate 100-200 watts essentially continuously for 30 minutes but this is not a leisurely pedal speed but me trying to do intervals and sustain near max heart rate.

Still, I'd pay good money for an actual high quality bike based system if it were designed for a comfortable workout and could actually harness 100-200 watts that the gym bike indicates.

One more reason...again...why I would recommend building your own from stronger components as opposed to purchasing the linked device.  ;D