DIY towed generator

[GILow]

Originally Posted by Jim Cate

Another source might be someone's retired Air-X. When the internal reg goes out, some folks abandon them, and they would make a useful towed array by substituting a bridge rectifier for the reg.

Actually, extending your thinking a little... practically any retired small wind generator should be an option... I will go see what is around.

[GILow]

Originally Posted by Pete7

Bolting one of these to the hull will enable the prop to be lifted out when not needed and provide an good platform to mount an alternator with a belt to the flywheel.

This one is mine but plenty of others about. the also have a variety of props including a big 5 blade slow turning prop for lager boats which might be more efficient.

Be an interesting engineering project .

Me I would just bolt a wind mill on the stern.

https://www.cruisersforum.com/forums...8&d=1287084700

Interesting idea. A lot of lost power in the transmission though. And my 1.4 meter freeboard would make it really hard to mount.

As for the wind-mill option, already have one of those. Love it. Except down wind. Then utterly and totally useless.

[Don C L]

So I am not sure if you have ruled these out, but if you have room and access to the prop shaft perhaps that is a possible way to go? Maybe you have seen some of these already, but there may be a few pearls of wisdom in there to draw on. I too am curious what you work out!
http://www.cruisersforum.com/forums/...aft-67467.html
http://www.cruisersforum.com/forums/...ft-182233.html
http://www.cruisersforum.com/forums/...aft-22266.html
http://www.cruisersforum.com/forums/...aft-84926.html
http://www.cruisersforum.com/forums/...ng-206443.html
http://www.cruisersforum.com/forums/...ator-2161.html
http://www.cruisersforum.com/forums/...ne-139664.html
http://www.cruisersforum.com/forums/...tor-31516.html
Shaft Alternators/Generator - Cruising Anarchy - Sailing Anarchy Forums
Prop-shaft generators


edit: oops, sorry Singularity, missed your post, you beat me to it!

[GILow]

Originally Posted by Don C L

So I am not sure if you have ruled these out, but if you have room and access to the prop shaft perhaps that is a possible way to go? Maybe you have seen some of these already, but there may be a few pearls of wisdom in there to draw on. I too am curious what you work out!
http://www.cruisersforum.com/forums/...aft-67467.html
http://www.cruisersforum.com/forums/...ft-182233.html
http://www.cruisersforum.com/forums/...aft-22266.html
http://www.cruisersforum.com/forums/...aft-84926.html
http://www.cruisersforum.com/forums/...ng-206443.html
http://www.cruisersforum.com/forums/...ator-2161.html
http://www.cruisersforum.com/forums/...ne-139664.html
http://www.cruisersforum.com/forums/...tor-31516.html
Shaft Alternators/Generator - Cruising Anarchy - Sailing Anarchy Forums
Prop-shaft generators

Thank you, lots of great links there.

But sorry to burst your bubble, I will have a feathering prop pretty soon (kiwiprop), which rules out the shaft generator.

Hence my desire for a towed generator.

The towed generator would only be used very infrequently, otherwise I would have considered the shaft generator with my current fixed prop. It is a good system.

[cyan]

Originally Posted by GILow

And there is the very problem. There are plenty of small Chinese units available, but nearly without fail they appear to be total crap. I am trying to find a good quality device.

Yeah, we probably just got lucky... with one that out-lasted its DIY prop rope. I think it was the same company that sold super-cheap wind generators.

[GILow]

Originally Posted by cyan

Yeah, we probably just got lucky... with one that out-lasted its DIY prop rope. I think it was the same company that sold super-cheap wind generators.

Can you remember who it was? And please don't tell me it's a company with the initials MWS because they looked really promising until I started finding reviews of some of their products. Yikes!

[wsmurdoch]

If you want to convert an automobile alternator into a low speed permanent magnet alternator yourself, there are instructions on page 171 of "The 12V Doctor's Practical Handbook". http://www.melody-in-blues.org/downl...lthandbook.pdf At least you would know what parts were inside and how to repair it, and if the watts output per RPM of the alternator while charging your battery did not match the watts available per RPM of your towed propeller, you'd be able to rewind the alternator so that they matched. (Like choosing the right gear on your 10 speed bike.)

Bill

[malbert73]

Originally Posted by GILow

Thank you, lots of great links there.



But sorry to burst your bubble, I will have a feathering prop pretty soon (kiwiprop), which rules out the shaft generator.



Hence my desire for a towed generator.



The towed generator would only be used very infrequently, otherwise I would have considered the shaft generator with my current fixed prop. It is a good system.

Interesting some feathering props will stay rotating if you set them in gear I think. Maybe like reverse? I forget the details but think it’s possible.

[Bill O]

Have one of these if you are interested. Since we changed directions to create power, it was never installed.

Tried the electric trolling motor before (w/the correct propeller design) and it didn't produce any meaningful energy.

There is a lot of info online re hydrocharger designs, so do more research about the proper design. As we used to say 1 hr. of research saved you 10 hrs. in the laboratory.


Bill O.

[GILow]

Originally Posted by malbert73

Interesting some feathering props will stay rotating if you set them in gear I think. Maybe like reverse? I forget the details but think it’s possible.

Yes, some do, but not the one I will fit. I am also restricted by having a hydraulic transmission so props that need the shaft locked to feather will not work on my boat. [emoji853]

[GILow]

Originally Posted by Bill O

Have one of these if you are interested. Since we changed directions to create power, it was never installed.

Tried the electric trolling motor before (w/the correct propeller design) and it didn't produce any meaningful energy.

There is a lot of info online re hydrocharger designs, so do more research about the proper design. As we used to say 1 hr. of research saved you 10 hrs. in the laboratory.


Bill O.

Thank you Bill, I might have been interested in that one. About the right size for my needs. But I fear the postage from your part of the world to Australia would be a killer.

Also, it is not explicitly listed as suitable for salt water. That might not be a big problem as I’d be inclined to remove the prop and put it on a towed line anyway. In part because my stern is so high, and already very cluttered, and in part because it would address the suitability concerns.

[roland stockham]

Have you considered using the propshaft? You are already towing it round so it introduces less drag than adding an extra towed prop. If there is room for a large dia pulley behind the engine then that can take power off to a standard windturbine generator. Not looked into it but I would expect a generator deained for a wind turbine would be ideal and efficent for this system.

[CapnCrunch]

Have you given any thought to using the new bladeless, wobble type technology?

[The Sun King]

Clamp a trolling motor to the stern. An 80 lb MinnKota is very durable and lasts for thousands of miles. Remove the electronics and add a fuse and a diode of appropriate amp capacity to keep the motor from motoring and draining the battery. You might want to run it through a solar charge controller to regulate the output and save the battery. This should be a cheap and easy solution to your need.

[MikeInMaine]

30 years ago when I lived in a retired boxcar, in the woods, in Northern Maine, and had just a few solar panels, I bolted an old 5hp 4 stroke B&S and a car alternator to a piece of channel iron and connected them with a drive belt. I think I used the internal regulator but also hooked up a switch to a rheostat so I could do a controlled overcharge. I had 4 big trojan batteries for 700amp hours at 12v. Got me thru the cloudy stretches. I worked at the local college as an IT tech so I had an old Televideo terminal and 1200bps modem for working from home (yes, we had phone but no electric service on the road where I lived). I had an early high efficiency Heart inverter.. ah life was simply back then...

Mike in Maine
P33-1 Brizo
Harpswell, Maine, USA

Originally Posted by GILow

Hi all,

I've had the idea to add a small towed generator to my arsenal for a while now. I dabbled with some half-baked concoctions a few years back on the trailer-sailor and I was pretty happy with the results.

But now that I want to make a "real" one, I cannot find a decent low speed generator for sale. There are lots on Ebay that are very cheap, but a bit of digging around and you discover plenty of very disappointed buyers. In short, they are cheap, but they are also mostly garbage.

Can anyone point me in the direction of decent quality low speed generator? Or maybe some web sites where such things are discussed that are not trying to sell me something? (My favourite site here in Australia, the Alternative Technology Association, has been offline for months.)

And just to save people from typing, yes, I do know about the various commercial offerings out there, but they are waaaay out of my budget. This is a cheap and cheerful extra for my charging, to cover running downwind at night when the existing solar and wind generator will not be much use at all and the wind-vane will have to give way to the autopilot.

Matt