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Hydro Generator

9 years ago
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nswsailor
nswsailor
NSW
1458 posts
nswsailor nswsailor
NSW, 1458 posts
13 Aug 2016 10:06am
Ramona said..
The average yacht sails at 4 knots [4 knot leadmine]. With a 240mm propeller it's going to generate 30 watts! Roughly 2.5 amps. Lets forget about the hp loss needed to get that prop revolving, lets remember there is no free lunch. So for just under 4 grand the average cruiser is going to get 2.5 amps while he is underway!

Propellers are very inefficient when driven. They operate at about 40% efficiency with major losses at the boss and tips in particular. Dragging one though the water the inefficiencies are still there but with added parasitic losses like drag. For 4 grand I could have a pretty phenomenal solar/lithium battery installation, enough to power a modest home!

Now if you were to develop a paddle wheel generator that would be more efficient but the size required would be a problem.


Absolutely true Ramona, even for a Top Hat but where would I put the B**** thing?
PhoenixStar
PhoenixStar
QLD
477 posts
PhoenixStar PhoenixStar
QLD, 477 posts
15 Aug 2016 10:51am
Ramona said..
The average yacht sails at 4 knots [4 knot leadmine]. With a 240mm propeller it's going to generate 30 watts! Roughly 2.5 amps. Lets forget about the hp loss needed to get that prop revolving, lets remember there is no free lunch. So for just under 4 grand the average cruiser is going to get 2.5 amps while he is underway!

Propellers are very inefficient when driven. They operate at about 40% efficiency with major losses at the boss and tips in particular. Dragging one though the water the inefficiencies are still there but with added parasitic losses like drag. For 4 grand I could have a pretty phenomenal solar/lithium battery installation, enough to power a modest home!

Now if you were to develop a paddle wheel generator that would be more efficient but the size required would be a problem.


Yes, and there is still no such thing as a free lunch. Using the yacht prop is quite batty, the blade curvature is all wrong and you are putting side load on your shaft and gear box bearings and introducing wear and friction to add to the losses.
Stuman92
Stuman92
WA
279 posts
Stuman92 Stuman92
WA, 279 posts
30 Aug 2016 11:40am

Look what i found in a Hartley book from 1983


HG02
HG02
VIC
5814 posts
HG02 HG02
VIC, 5814 posts
31 Aug 2016 12:12am
www.yachtingworld.com/gear-reviews/wind-water-and-solar-power-65797

Stuman92
Stuman92
WA
279 posts
Stuman92 Stuman92
WA, 279 posts
31 Aug 2016 6:04am

There Definitely is no one solution that's for sure.
Ramona
Ramona
NSW
7752 posts
Ramona Ramona
NSW, 7752 posts
31 Aug 2016 8:38am
HG02 said..
www.yachtingworld.com/gear-reviews/wind-water-and-solar-power-65797



Good article. Once again they seem to concentrate on people who sail 60 footers and have an excess of power that wont notice that drag through the water. Most cruisers spend 98% of their time in harbour, 1% sailing and 1% motoring. Most anchorages or marinas are sheltered so wind generators are useful probably 2% of the time. That leaves solar and that's where we will see constant advances in technology. Along with batteries of course too.
HG02
HG02
VIC
5814 posts
HG02 HG02
VIC, 5814 posts
31 Aug 2016 10:26am
Those TESLA house modules one day they may at make compact unit for rvs and marine use
nebbian
nebbian
WA
6277 posts
nebbian nebbian
WA, 6277 posts
31 Aug 2016 8:37am
Stuman92 said..

Look what i found in a Hartley book from 1983



Wow, 20 amps per hour? Gosh.

Does that mean that at the start, it produces 0 amps, and then by the time an hour is up, you'll be getting 20 amps?

If I buy one and run it for 10 hours, then will I have 200 amps? I wonder if the wires are rated to 200 amps?


It should come with a warning. "Must not be run for more than 40 hours continuously, or you are likely to cause your boat to catch fire".








Stuman92
Stuman92
WA
279 posts
Stuman92 Stuman92
WA, 279 posts
7 Sep 2016 5:21am

Well turns out the 4.5 evinrude of mine has died, so im going to have a crack at converting it to an electrical outboard that can also work as a drag hydro generator. considering it requires practically no extra "ingredients" it should keep it small and simple.
Ramona
Ramona
NSW
7752 posts
Ramona Ramona
NSW, 7752 posts
7 Sep 2016 7:42am
Stuman92 said..

Well turns out the 4.5 evinrude of mine has died, so im going to have a crack at converting it to an electrical outboard that can also work as a drag hydro generator. considering it requires practically no extra "ingredients" it should keep it small and simple.


The first part sounds good. There will be some losses through the gearbox though. The prop might need modifying too depending on what electric motor you have in mind.
Stuman92
Stuman92
WA
279 posts
Stuman92 Stuman92
WA, 279 posts
7 Sep 2016 6:49am

Ill be using a permanent magnet low RPM motor, i will try and use/build a more suitable gearbox.

looking into motor options today.
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