Electrical Issues

[seamanstain]

Hello Again,
I need to get a completely new electrical system for our boat. Its only 18'6 long and the engine does not charge the batteries. We shall be living on board for 2 months and need to be able to run a small black and white chart plotter, echosounder, vhf and cabin lights. We shall be using low wattage LED cabin lights in order to save power. My question is what size battery to get and what is the best way to charge it. I was thinking of solar power as the boat is to be kept in the south of france but what sort of wattage panel will need? Any advice, as always, will be greatley appreciated!!

Many Thanks,
Ian

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[ccscott49]

Tall order! A chartplotter will drain a battery pretty quickly. I doubt a small solar will do it and a decent sized solar is very expensive. But to be honest if your engine won't charge a battery, you are stuck with either a small genny, or solar. By the way, I've not heard of even an outboard, that doesn't have a small battery charging capacity. I would stump for a cheap (try Ebay) suitcase size petrol genny and a 130 a/hr battery. IMHO

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[aod]

Hmmmm I agree. I am surprised if your engine doesn't have some charging capability but I guess you know your own boat well enough.

In a nutshell solar panels are crap. I have a 30 watt panel and you are lucky to get a couple of amps out of it on a bright sunny day. Personaly I think a wind gen is probably a better bet but by the time you have shelled out for that backed up with a solar panel you could have an engineer to fit an alternator to your engine and have solid dependable power.

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[seamanstain]

Hllo,
With regards to the engine, the one we use to motor the boat we also use for our tender. About 2hp I think it is!! Trusty though it is I don't think it will be able to have an alternator to it. After much thought I think we're going to invest in some oil lamps!!! Its about all we can afford really. thanks for your help

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[squidge]

A wind gen would be more friendly that the generator when near others and wouldn't cost you fuel. As for the batteries buy 2, the best deep cycle ones you can afford 100ah min ,oh and a charger so you can plug into shore power when you are able,you will be surprised at how much power you will use. In hotter places how nice would it be to have chilled wine or beer ( small low cost coolboxes available).
Have Fun
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[Guest]

Go down to a breakers and purchase a suitable output, alternater off a car (Bosch are always good) for about £10-00, make a bracket £5-00 and fit a spare pulley to your crank or maybe there is aready one there and connect it up with a belt and a few bits of wire (£3-00) its not difficult, dont mess about with photovotaic panels they are for use in space not on a boat, thats why not many of us can afford them yet. Do use two batteries with a splitter diode in the circuit so as one becomes charged the alternator continues to charge to other one.
Hope this helps you with your problem.
Regards,
Rob

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[LadyInBed]

You don't say if you will mainly be anchored or tied up alongside. If you are running on a tight budget, I would suggest a long extension cable, ordinary Halfords style battery charger and a mains reading light for when you can get shore power. For when you can't, you will need a fold up shopping trolley to wheel your battery to the nearest garage or, armed also with your battery charger, to the local Yacht Club or Harbour Masters office, and ask them nicely if they will charge it for you.

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[yoda]

Have to disagree that solar panels are c**p. They may not do what you want but they do provide a small charge over long periods of time. For some of us that is exactly what we want and not the noisy whine of a wind generator or the thump of an engine or generator.

Yoda

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[VicS]

Re: Solar panels

I also disagree that solar panels are c**p. I count my little 5watt panel as one of the most useful extas I've bought; doing just what I wanted ie charging between wekend outings. Clearly for long periods aboard something bigger will be required.

There are regularly articles in PBO showing how to calculate power requirements. One this month isnt there?

For a small boat I would seriously look at one of the vertical axis wind generators(Forgen).

Suggestions to fit an alternator to a small outboard are impractical and in my experience even the electrical outputs from slightly larger outboards are not much use either, hence the solar panel.

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[bedouin]

Re: Solar panels

I've heard that the vertical access wind are pretty well useless - not generating significant output until the wind gets to 20kts+



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