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Right lets have it you experts ,Solar Panels or Wind Turbine do they do the same job power wise ,can I run a boats electrics with the power put out by iether of these bits of kit?

Asked by: Andy Durler  | 1.27pm, Sunday 26 January

WW says:

If you have large enough solar array or a big enough wind turbine (and sufficient battery bank capacity) the answer is "yes, you can run a boats electrics". However, the first thing you need to work out is how much power you actually need on a day-to-day basis.
Solar panels work well if angled to the sun- which is fine when moored but they then, if mounted in frames, have to be lowered for cruising. Also, any shadows crossing the panel (even from mooring lines, etc)reduces the available power substantially. Those that are mounted flat, or semi-flexible panels are less efficient but easier to deal with as a cruising boater. Monocrystaline panels are more efficient than polycrystaline, which is turn are more efficient than amorphous panels. For a residential boater, you probably need at least 200W of panels, and be very judicious in your use of power. The more you can fit, the less furgal you can be with power- even then enough for limited 230V power via an inverter.
The charge controller is an important piece of kit- modern maximum power point tracking (MPPT) are the best and can improve charging rates over more conventional pulse width modulation (PWM).
Wind turbines tend to be higher output and can provide some serious power- however, they can be noisy, transmitting vibration to the boat. Also, if they are not well secured, they can be problematic in high wind speeds. Depending on where you moor, they might not be as efficient as you would like, as building and the lie of the land make wind turbines that are only say 10ft above water level far less efficient than those much higher up. Also, some turbines have relatively high start-up speeds, while others start from quite low.
Some moorings will not allow wind turbines, as they can be antisocial,. They are also a paint to raise and lower, unless you are smart with the mounting and guying system, which can make cruising with them difficult. Like solar panels, they also need good sized cabling between the unit and the charge ocntrollers- often panels and turbines are fitted with too thin cables, which increases voltage drop and leads to poor performance.
If you want to be independant of shore power and running the engine, you probably need to have both solar and wind turbines. During winter months, solar might only produce a tiny fraction of your electrical demands, whereas a wind turbine might give you everything you need- and the opposite in summer sometimes.
Calculating what you need from your electrical system is the first stage of working out what is best for you- and then taking time to see how light (and windy) your moorings are. If you have trees or shade cast across your boat, the solar panels will not be effective- and if you are urban, then wind turbines might not be as good as you want.
If we can be more specific, then please let us know. However, a good starting point for a independent power set-up might be four 110Ah decent leisure batteries, 300W of solar panel (ideall rigid in mounts) with an MPPT charge controller and a medium wind turbine (like the Rutland 914i). That would, with careful use, probably provide enough 12V power and occaisonal 230V power supplies.
Hope that helps!

Mark Langley  | 2.36PM, Sunday 26 January

I have no experience of wind turbines but I do have a 70W solar panel fixed flat on the roof of the boat. It provides a maximum of about 3.2 amps on a sunny summer day but nothing at all on a dull winter day.
Shortly after I installed the panel, I switched to LED lighting throughout the boat. This obviously does not provide power to the batteries but it does reduce the amount of power being taken out of them by a considerable amount.
Installing LED lighting will therefore increase what ever benefits are gained from suppliers of green energy by reducing the load on the batteries, so it is definitely worth considering as part of the package.

Graham Booth  | 3.15PM, Sunday 26 January

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