Electrical power generation on a small yacht

[Phoenix of Hamble]

Here's another vote for a wind-gen.... we've got a Aero4gen, and its virtually silent, and generates a very decent amount of charge.... certainly when the wind is above 6 or so kts true or apparent, it provides enough to run most of our on board needs while moving, and when anchored it helps to top the batteries up nicely..... and if the true or apparent wind goes over about 15kts, it is enough to run the fridge, autopilot and basic electronics, and still put a little charge into the batteries....

 

[trouville]

Another idea, very inexpensive!

I bought a small portable "Jump starter" battery the small one i have cost £12 and will run the autohelm,VHF, charge the phone and last at least a day

When i was in the north with grey cold wet august weather my main and only battery died!! went from 12v to 11.xv then one morning it was 9.6v dead!!

The small sealed battery with handel neon light and strob has a cigar lighter socket and large crocdile clips as jump leads.You must have seen them there sold everwhere? I just dropped the old battery overboard cliped the leads on to the treminals and pluged in my telephone charger

With my solar panel (just one then) it kept everything going for the rest of the week!
Later i tried it running the autohelm and VHF left on standby and it ran them allday and still had 11.8v that evening. I used a 25w haligen lamp for another 2 hours continuose before it began to dip a bit

For the price a good emergency back up

 

[bluedragon]

Thanks Trouville...actually that gives me another idea. I know I need a second service battery, but have an engine start battery doing nothing for 99% of the time except taking up space. I'd consider tapping into this for backup service needs if I had another "emergency" start battery available. I'll look into this...

 

[extravert]

I'm not going to make any recommendations about how to run a low electrical power boat, because when I have done this in the past, the 600 Amp Hour battery brigade have rubbished my suggestions.

However, I do successfully run a low power boat, so instead of telling you what you should or should not do, I'll just say what I do.

My boat is a lightweight Dragonfly 920 trimaran. It has no inboard engine, just a Yamaha 10hp outboard. This generates a maximum of 12 Amps of electricity. I also have a 30 Watt solar panel. I carry a tiny mains charger, only 3 Amps maximum output, which gets used if shore power is available.

The way I make this work for extended trips away from shore power is by minimising usage rather than increasing generating/battery capacity. For example...

LED nav lights
Oil lights for interior and anchoring
Hand steer much of the time
Switch off unnecessary instruments.
Only use GPS and chart-plotter occasionally.
Only put already cold items in the fridge (a miserly Waeco compressor coolbox)
Avoid night sailing if possible
No computers, radar and other heavy power consumers.

I get my summer consumption down to 10-15 Amp-Hours per day. I only motor long distances when sailing is not possible, which for a trimaran is not very often. My normal day to day motoring on summer trips and the solar panel keeps up with consumption. I don't have to go to a marina just for shore power, and I have never run the engine just for charging purposes.

On a similar trip to your planned excursion I made last summer around the Irish Sea I was not connected to shore power for the whole trip, and the batteries (120 Amp Hour in total) were fully charged on returned

It can be done. A miserly attitude to consumption is needed.

 

[Guest]

Actually Trouville has a point ...

Mate of mine bought a "Power-pack" .... emergency start and power pack .... not a bad idea to have on hand ...

I keep looking at them ...

Other idea I looked at is the sealed alarm style battery - hook that up as emergency supply for Nav / VHF etc. .... have an auto charge so when plugged into shore - is charged - same as when on wall of your house in the red box !!

 

[trouville]

Re: Actually Trouville has a point ...

The very cheep jump starter battery may say it will start a car engin??!! for that i certainly wouldent rely on it!! Not even the cheep bigger start batteries

If you buy a proffesional garage jump start battery it will work and be reliable but cost a fortune!!!!!

The cheep ones are easy handy and work!! Being lead they ought to be good for 2 years even when treated badly but at £10/£15 when its loosing its charge just drop it overboard before going to buy a replacement!

Attention!!!! Mine came only a bit charged and i thought it was useless but now its charged it holds 13.8v for weeks!!!(im going to look now as i havent checked for more than a week. Its 13.4v!!! Not bad

The one i bought in Lidel sweden is the same size as the French one and cost 199 Krone ans is black i has plugs for 3v 6v 9v and 12v very handy for running the AM radio and CD player
I havent seen one like it again only a larger model which cost £40 and only had 6v 12v and compressor!!!

My French "Jumbo"one has only 12v out but has a neon light which is useful

 

[LadyInBed]

Methanol fuel cell charger - £2,300 !!!!!!!! /forums/images/graemlins/laugh.gif

 

[bluedragon]

Thanks Extravert...I certainly won't rubbish your suggestions. I love my electronic gizmos and tiller pilot and would be loathed to switch them off, but much of what you say makes sense. I'm going to run-up a few different scenarios to see what I could do on longer trips to cut consumption. What type of solar panel do you have (make, silicon type??)...any idea what on average this contributes to your daily power usage?

 

[Bodach na mara]

For info on battery state, you can get by with a cheap digital multimeter.

Maplin sell them for about £5.

A charged battery should show 12.6 V, One that is charging should show about 14.5V and if it shows only 12 V, it needs charged. No doubt someone who knows better than me will correct these voltages. The main point is that you do need the decimal place and an analog (moving needle) meter will not do, even if it is £180 worth of AVOmeter.

 

[bluedragon]

Re: Actually Trouville has a point ...

Halfords have what seems an OK one (but it is around £35-40 I think)...if it doesn't start the engine then it's back to the shop for a refund! It's only a mile away...might pop down and have a look at one. The time to find out how good these are (or not) is now whilst I'm tied to the pontoon!

 

[trouville]

Re: Actually Trouville has a point ...

I did try to start a small engine a 25hp when i first bought the French one then found it wasent charged!!

Ive now realised that if i use a battary to start an engin and that batterys to small it will start the engine but will reduce the power and life of the battery!! Just think or the diesel starting battery.

Mines stayed at 13v+ when charged? I use a digital meter but have noticed there not all reading the same!! One reads almost 1v more???? I thought the digital were better as well!!?? But the old avo (a bit big for my boat) MK 7 reads voltage well enough but its the resistence its only about 1ohm per volt!!! not millions and for modern transistors wasent sensitive enough

 

[William_H]

Thanks for the response Bluedragon if you used a rheostat charge control the easist thing would be to fit it with a timer to ensure that it reverted to normal regulation say after half an hour depending on the current and AH you estimate you need to resore.
Poter the best method of battery charge estimate seems to be the battery monitors which compute current discharge over time versus recharge over time. However if that is not to your budget I think a voltmeter firstly then an ampmeter so you can know what you are putting in and what you are taking out. A hydrometer shows the battery fluid acidity which is an indication of charge state. However I think you need to graph the results over a period of time or at least know the SG when known to be fully charged and SG when known to be fairly discharged. This will enable you to interpolate charge state. A battery can function with an inherently high acidity or low acidity fluid so it is the variation of your batteries fluid that matters. They only work on open celled batteries of course.

Otherwise use a voltmeter but check it often as the charge state can only be indicated by voltage if it is checked a fair period after discharge or charge. It is not as easy as you might imagine. olewill

 

[LORDNELSON]

Some random thoughts which may be useful when you look at various scenarios; 1. Solar panels, once you have calculated the panel output you require, consider the size of panels and cut out pieces of cardboard to represent the panels and then check where you will place them and if using a pole what it will look like, strength etc., Once in place check how much sun will reach them, shadows etc., 2. Petrol genny; some people worry about carrying petrol on a boat and it is dangerous stuff, however, if you use an outboard the chances are you will carry some petroil in any case so I do not think an additional gallon will make much difference. I carry mine in shaded tanks on the deck and EMPTY the genny tank before putting it in the cockpit locker (although good gennies will have sealing tank tops). Size and weight are a problem with gennies and I reckon you have to spend the extra and buy a Kipor or Honda. 3. I am impressed by the owners who say they have quiet wind gens, I have also, at times, been very impressed by the noise of wind gens on boats near me! Chances are that you will generate electricity by wind gen when sailing, but when in harbour, look at the wind gens which are not rotating or not rotating fast enough (of course they also do rotate fast at times in harbour but you may be in an area protected from wind ). Make sure the windmill is high enough and remote enough to avoid hitting people. Boat in Shoreham cut a chaps ear off a year or two ago.

 

[richardandtracy]

I must admit to using very little power.
Cool box with ice, no fridge. Internal lights are paraffin - give heat too, I've almost never been too warm below at night.
Wind generator. Why make it expensive? I made mine to Hugh Piggott's 'Brakedrum Windmill' plans and reduced the blade size to 4ft diameter. Even made the alternator for it. The windmill plans I used are no longer available they've been updated in the new book 'How to build a Wind Turbine'. This can be got here http://www.camdenmin.co.uk/Altech1.htm - see third book down in list.
I modified the brakedrum design to include a slip ring, but otherwise it was fairly easy and cost around £20 to make in 1996, though I did scavenge many bits for nothing.

Regards

Richard.

 

[bluedragon]

Just an update for you all on wind generators. I walked along the pontoons this afternoon looking at the various models (up to about 10 knots easterly - fairly steady). I can't comment of course on power output, but here are some observations:

The one whizzing around in 10 knots and absolutely noiseless was the little Rutland 503 (and boy is it little! Almost looks like a toy, and if you don't look hard for them they are easy to miss). Now if this gives say 1-2A in 15-20 knots of wind it might be worth consideration especially at £250, even if just to replace my Forgen.

The small Aero2gen was a bit larger, but seemed to be running a lot slower.

The Aero4gen is not a bad size, but the Rutland 913 just looks too heavy. Most of these two seemed to be feathered, locked or barely turning for some reason? I'll go back when there's more wind.

Another one going (and sounding) like a train had a wierd tail fin...it might have been an Air-X...but too large for me.

My visual observation is that if I want to use wind as a component of the charging system, then either the Rutland 503 or the Aero4gen look like good candidates for a small boat.

 

[DaveS]

Quite.