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Trailing Dynamo - battery charger

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Silenus View Drop Down
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Post Options Post Options   Quote Silenus Quote  Post ReplyReply Direct Link To This Post Topic: Trailing Dynamo - battery charger
    Posted: 24 Feb 2013 at 5:29am
Hello, 

Having successfully sourced an unused and boxed Walker Log I am wondering if any one may know where to find a Towing Dynamo.  There will be a correct name but i do not know what iy is - basically I want to charge my batteries as I sail witha trailing spinner.  They exist but i do not know what name to search under - can you help me :) 

With thanks  
Martin
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Richard Ritchie View Drop Down
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Post Options Post Options   Quote Richard Ritchie Quote  Post ReplyReply Direct Link To This Post Posted: 25 Feb 2013 at 9:16am
\but why not solar panels?
Others will have links to trailing logs . 
I want to question them as an option, especially in Singapore.
Solar panels are simpler, have reasonable output, take no space, do not tangle with the log and keep going even at mooring.
I would not be without them: and they keep up with the fridge etc in UK mid summer.
I am sure you will have thought about this, but it does bear mentioning again...
Richard Ritchie
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George Isted View Drop Down
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 25 Feb 2013 at 10:21am

I think you are after an Aqua4Gen or Aqua6Gen made by LVM, I have not used one but they can produce good amps if you don't mind the additional drag.  They come up on eBay every now and then, so with setting up a weekly search.

 

Personally I prefer the Solar approach along with reducing the amount of power used

George Isted
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Post Options Post Options   Quote Silenus Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2013 at 6:14am
Thank you for your reply.  I agree on Solar Panels and these are part of the charging strategy and a very good idea.  However, since I am contemplating some long distance trips as I return Silenus to the UK I tend to feel some alternative options are a good idea also if easily done.  Thanks
Martin
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Post Options Post Options   Quote Silenus Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2013 at 6:16am
Thank you for your reply and for the advice.  I expect I shall do both the Aqua Gen being part of the back up plan.  Never a bad idea when off shore for a while I reckon Smile.   Thanks 
Martin
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Post Options Post Options   Quote Silver Harmony Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2013 at 9:35pm
I have an Aquair 100 towing generator (http://www.ampair.com/yacht-generators/aquair-100) on Silver Harmony. The alternator is suspended from the pushpit and the impeller is towed on a 30 metre rope behind the boat. It is great on ocean crossings where I found I had far more electricity than I could use. There is a graph of output amps vs boat speed in the data sheet which is more or less accurate. If there is enough wind that you are going fast enough for the machine to give useful output, you will hardly notice the loss of boat speed, I reckon less than 1/4 knot. It's less useful for coastal sailing where trailing and recovering it seems a lot of effort and you're always worried about snagging the impeller on a lobster pot or indeed the sea bed in shallower water.

I fear it will not get on well with a Walker log, I suspect the two lines will get tangled and you will end up with neither electricity nor log reading.

I am curious to know where other people have installed their solar panels. A rigid panel with the same rated output as the Aquair (100 W) is over a metre long and half a metre wide and I can't find anywhere sensible to put one.
Robert Fox
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Post Options Post Options   Quote Richard Ritchie Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2013 at 10:19am
We have a single 20w "Aurinco" panel lengthwise on one side of  the coachroof.  Safe to walk on.
This is1200 long and only 150 wide.  So lots of room for 3 more if you want! Or put a 40w unit on each side.
Shading has not proved a problem.

But surely power reduction is a better solution.  100w seems huge.
Our greatest load is the autohelm, and I would replace with a vane steering gear.
Then the fridge: much better now re-insulated.  (But may need more power on long tropical passages?)
LEDs complete the picture. 

 .


Richard Ritchie
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Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2013 at 11:34am

You can get away with solar panels with much less output than a towed generator as they are working all the time in daylight hours, although I’ll admit that output is low when the sun is low in the sky or cloudy.  I guess with a towed generator you put it out when needed and then recover after a few hours.  I have a solid framed solar panel attached to the side of the pushpit than can be angled to the sun, I did have a second one that I would temporarily attach to the coach roof when offshore but that has now died.  I’d be tempted to replace it if going offshore again for an extended period or put a second panel on the pushpit.

 

The towed generators do look like a good option for cruising offshore, but if racing I don’t think I would want the drag.

 

I found that with a total of 55W of solar panels and a domestic bank of around 200A/hr in good weather we would be pretty much self-sufficient on power, in reality with changeable weather and cloud cover we would run the engine every 4-5days for half an hour to top up.  That said, we were not running a fridge and do have a Stirling smart alternator regulator.

George Isted
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Post Options Post Options   Quote Silenus Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2013 at 12:31pm
At this point our Power needs are low since we have no fridge and we have a Wind Pilot self steering, Instruments draw very little I would say so based on all the comments and where we shall be, namely the Indian Ocean, a solar charging solution may be the best way for the time being.   The Ampair looks like a good solution I may come back to later.
 
In the meanwhile it may be not been known to some that in the West Marine catalogue can be found flexible/role up Solar mats designed apparently for the US Navy which come in a range of sizes (depending on desired output) and it seems to me fitting one each side of the boat facing into the cockpit, basically of similar size as the Dodgers lining the inside of each dodger if you like and one 6 foot long one laid and then fastened over the sprayhood may be a tidy solution (not cheap though maybe).   Hopefully not a daft idea - not much risk of being stepped on or damaged whilst moving about as I see it.
 
One final question if I may - keeping with the theme I think - so I fit the Solar panels, I have two battery banks.  Can you recomend a suitable choice of charge management system for pluging these, and possibly the ampair later,  into to ensure I do not boil the batteries, and everything else by day, and drain them by night ? Thank you
 
 
Martin
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Post Options Post Options   Quote St Paddy Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 2013 at 12:00pm

Hi. Good reading, My friends have the Aquair 100 and used it on their Westerly Consort when they crossed the Atlantic, they won't sell it I asked.

Bardens are selling some panels 150W that hang on the guard wires, look tidy. very expensive. I like the mat but lower output, might just have it on the cotpit seat and roll it away when not used or things are too lively. Please add your thoughts on this.

I don't want to fix anything on the decks, looks untidy. Fussy I know. The towed generators can be hard to recover, seems you have a fuel funnel with a split in the side that you fit over the line tape it up and let it slide down to cover the impellor. stops the spin and the tangle. I wonder if it could be a source of a problem.

Use less power and have panels is the answer, we need to refine the plan to suit our restricted space.

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