Hand cranking 12v + or - dynamo

Neeves said:
I've never seen one of these before (but then - I've never looked!):
I'm not even sure if it is useful?
Click to expand...

The technology isn't new - which makes you instantly wonder what you might be missing about why its never been done before.

The voltage spec is massive - 3 - 28V, 1.1 -3A. So I would take that to mean you can have 3A at 3V? so 9W but 1.1A at 28V ~30W. RPM is 90 / min which I think will get a sweat on for arm power even without a load.

Lets assume you want 12V and are going to charge a 12V battery with it so actually want 14V, And lets assume 10W of power output so 1.4A of charge. Assuming no inefficiency and your battery is able to take the charge (erm remind me why you are charging?). If you want this as a backup power for your VHF you'd need to be powering it up for 3 times longer than you transmit. and then you'd need to keep powering it while you listen. So lets assume you have a 90 second discussion with CG and 5 minutes of listening. You probably need 10 minutes of powering up. AND that all assumes your battery etc were in a state ready to take the charge.

My mobile phone will charge (slowly at 500mA) - I think I'd be able to charge it from this via a buck convertor or something similar. But would need continuous "arm peddling" for 20 minutes to even get me 5% charge.
 
Sorry, maybe I was, very, unclear - I know of dynamos etc, really old technology - it was the hand cranking (and - yes I did think it might generate a sweat). Pedal power would be much more sensible. (and you could exercise and charge your iPad, apparently with some further complexity, all at the same time). It was the idea of having a fall back, in the same way people have hand operated de-salinators.

I did mention I was not sure if it would be useful - Shinyshoe seems to have clarified that! :)

Jonathan
 
I believe they have wind up radios in Africa too.

Trevor Graham Baylis CBE (13 May 1937 – 5 March 2018) was an English inventor best known for the wind-up radio. .... "This $40 Crank-Up Radio Lets Rural Africa Tune In". New York Times. Retrieved 7 March 2018. Jump up ^ Quinn, Ben (5 ...
Awards‎: ‎OBE‎ (1997); ‎CBE‎ (2014)
Nationality‎: ‎British (Wiki)

https://en.wikipedia.org/wiki/Trevor_Baylis
 
A very unsophisticated device as others have posted.

A table to show how much useful power a human can create.

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Neeves said:
I've never seen one of these before (but then - I've never looked!):

https://www.alibaba.com/product-det...tml?spm=a2700.9171878.c2059.61.378d3MCL3MCLDj

I'm not even sure if it is useful?

But maybe interesting, particularly those who cannot rely on solar.

Jonathan
Click to expand...


Unless you're north of the Arctic Circle, I would have thought that solar's one of the few things that could be relied on.

I've had a Degen radio for a few years that can be charged from solar and hand crank, and has a USB charger that can be used to charge a phone. The combination of an all-in-one FM/MW/SW radio, torch and phone charger has proved to be very useful.
 
The dynamo in the link is very interesting. It seems to picture another box with a volt meter and variable (voltage?) control. I wonder how they vary the voltage given that it seems to have a permanent magnet generator. The trick is to match the best natural speed and load onto the arms to get the most power then to get the correct voltage out for your requirements. ie 14v. What might work well with it is an MPPT controller to automatically get the best power from what you can input.
Historically Alfred Traeger in around 1920s and 30s designed and produced the pedal radio for the Flying Doctor Service. By pedalling this produced enough power to light the filaments of a valve receiver and transmitter and produce a high voltage for receiver and also for transmission on HF AM. Apparently was suitable for diminutive house wife to operate. Many were built. The pedals being mounted under a table on which the radio sat. So different now as outback stations get satelite TV telephone and internet. Anyway it should be easy to power a VHF receiver transmitter.
Interesting is that a flat (discharged) 12v battery can get enough charge (from a charger) relatively quickly to crank an engine. All provided it is a good battery. So perhaps this could save the day on a boat. But I think I would rather rely on a 2 battery system. olewill
 
Interesting comments.

Some decades ago we cruised (and more often raced) a J24. It had no battery, nor means to charge one. It had a small outboard, don't recall the size but no charging facility. Nav lights were dry cell battery powered. We had no need for house battery - a mentioned we did not have one and there was nothing, then, that needed power - no, we had no VHF either. We had hot water showers, those black poly bags you leave on the deck. Life, on the yacht, was very simple. We had a camping stove for meals.

Thing have changed in the intervening years.

Maybe now people start off sailing with all mod cons - which makes me wonder what happens to all the smaller yachts (that were good enough for some of us then) and how the younger are encouraged to take up sailing - maybe they need rely on their parent leaving a generous bequest (by which time they might be in their 50's!).

One thing that has changed are our need for electronic devices (and maybe also a VHF radio!).

It seemed that this dynamo device might be the fall back with no means to produce power (knowing how often electronic devices seem to consume power to the point where they cannot be used). I'm encouraged in thinking the mobile phone and its short lived battery is a real issue as I see tomorrow's leaders (or some I assume) clustered round power points at airports and rushing to a power point when they come to visit us.

I confess I found it difficult to see how anyone could pedal, by hand, the device illustrated - it needed to be fixed to something in order to allow ease of use - but that did not seem insurmountable.

Obviously if you, at 25, have a larger yacht with inboard, alternator, home battery bank, engine battery, nice solar display and wind - then a hand operated dynamo does seem inconvenient, unnecessary and maybe archaic (and raising a sweat is so 'very 20th century' - that's what gyms are for). Olewill suggests the concept is not so daft, in times gone by, and I do wonder if, with a bit of ingenuity, it is not a solution to someone's problem.

I also recall articles in a number of different sailing magazines - how to stay fit when long term cruising???

Maybe its a solution to a problem decades ago and our youth will not cruise a J24, without any electrics, today - Ransome must grimace. And possibly I'm a romantic - but keen to see youngsters given the opportunity to try sailing.

Jonathan
 
Neaves

You mention electronics/electricity on board yachts.

We have an annual race the Sydney/Hobart race starting on Boxing Day each year. The maxi yachts (which always win line honors) have swing keels and enormous sails. To swing the keel from one side to the other they use hydraulics powered by the engine and the winches are powered by the engine also. It is all push button. I wonder if they have an electric stove, fridge, TV, hot showers and air-conditioning powered by the motor as well?

What an absolute farce.

Clive
 
I know I live nearer the start line (and finish) than you do :)

There is nothing wrong with the enormous sails - if you mean the power necessary to work the rest - I agree. Its interesting and another contradiction - but they will not allow multihulls to compete (because they are not real yachts?). I assume they do not allow auto-pilots either - but cannot think how they justify that.

Too much sailing, yacht design/building and particularly yacht racing is conducted on the basis of - just throw money at it. There is a tendency to forget that for quite a few people - owning a basic yacht (accepting basic to some might be luxury to others) is all they can afford.

I'm the first to admit I'd much rather have a WattnSea water generator or a big solar bank than the need to become sweaty turning a dynamo - but they are hardly cheap (WnS nor solar power banks) and only generate 'real' power if you move fast or live in the sun (like you and I do, live in the sun - I mean - I don't know if you are a fast mover :)) - and both need a bigger yacht (than an engineless J24).

The Sydney Hobart is a different form of yacht racing to that conducted when it was initiated and we have moved on. Sadly the winner, now, is the one with big pockets - and that's the farce, buy your helmsman, navigator, tactician, one's muscle (the sails are heavy) and as long as your yacht does not break nor hit a sunfish you to can win the cup - you don't even need to be on it - and you can win - bizarre.

I'm not a Luddite - we have GPS, solar. hot water etc etc - but I try to remember when we started sailing (and climbing) and assume youngsters today who are keen will do so with the same minimalist resource.

Jonathan
 
Generators similar to those linked to in the OP are quite widely used in certain military kit.
You can crank 50W or so quite easily, which is enough to power a fairly useful radio system for instance.
Solar is not always discreet enough!

Maybe not something the average yotty has a use for.
But there is interest in small electrical sources other than solar.
'Energy harvesting' to power small data radios was something we played with a few years back.
 
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