I would suggest a simple system with a 12V or 24V battery pack, a marine turbine and an inverter. I lived on a boat for three years powered by a small Ampair machine, but for a fridge and television, unless you have exceptional winds, you may need somethig a little bit bigger. For summertime coverage (particularly the fridge), I would add in a solar PV panel and a solar controller.

My preference would be for 24V – if you increase the voltage, it reduces the current and the required wire sizes. You can still get 24V bulbs and inverters, and later if you want to build on the system, you can get larger inverters etc., that all work on this voltage.

The batteries are the critical issue. If you buy a suitable battery, and ensure that you only ever discharge it to 50% of its capacity, it can delivery up to 2,000 cycles. Most deep cycle batteries from golf carts and fork lifts are not particularly suited for off grid systems. This is because they are not designed to spend long periods in a state of low charge, as often happens in off grid systems.

We can supply suitable batteries, and solar PVs but for the turbine, inverter etc., I would rummage around the yachtie mags. Q

We have a small cottage in the country & we are still using tilly lamp we think it’s time to move forwords a bit and stay eco, we would be just looking for a turbine to power up, lets say three light bulbs, a fridge, a t.v. have you any idea what type , brand of turbine would suit our needs, we would be very gratefull if you could help, many thanks

Most wind turbines have three blades with a fairly broad blade to provide structural integrity. A single blade would only catch all of the wind going through it if it was rotating at a very high speed in relation to the wind going through it. The optimum turbine would have an infinite number of infinitely narrow blades.

The turbines you see used for pumping water etc., are usually required to rotate at a fairly constant speed, regardless of the winds speed. You don’t need more water on a windy day. Above a certain RPM, these turbines self-stall as one blade causes turbulence on the next one.

Wind turbine blades are generally hand laid up and are expensive to produce. On larger wind turbines, if you had two blades for example, the wind speed is higher for the blade that is reaching upwards (at 12 o’clock) than for blade at 6 o’clock. The turbine shaft will constantly be twisting this way and that. For that reason, they have three blades as the blades at 4 o’clock and 8 o’clock more or less balance the opposite load on the uppermost blade.

Smaller turbines have three blades mostly for economical reasons, but once they get up to their working speed, they do capture all the wind running between the blades. At lower wind speeds, and correspondingly lower RPM, they tend to lose some of the wind.

We found that six blades work very well at lower rotational speeds, and this reduces noise at high wind speeds, and increases output at low wind speeds. Our blades are injection moulded, so once the mould is paid for, the price per blade is quite low. So it makes sense for us, but not for everyone…

There is a paper here which provides more info on all this.

Best wishes, Quentin.

These have mutiple blades that would seem to fill up more area of the wind catchment. I didnt look up why but no doubt science and wind tunnel/computer modelling has determined that ‘less is more’. Maybe there is some research on the topic that you have found or can point me to?

Best Wishes for the Year,

Martin

Regards
Chris