Electronic equipment has for many years been designed to be driven by constant Direct Current voltage, most commonly 12vDC.  Some companies prefer to drive their electronic LED's by giving them a constant current (amps or milliamps) rather than constant voltage.  It is cheaper to manufacture than a constant voltage driver and you get max light output from the led..
Their is a problem with this, particularly when switching on.  Often the electronics delivering the constant voltage do not switch fast enough, so if the load (led's connected) is very little, then initially the current output of the driver is too much for the LED and it pops.  In other words, the driver needs some time to balance the output load to the draw being called by the leds in the circut.  This time to take to balance the load may be too long for the diodes on the circuit.  At the same time this device will fully drive the led at all times, which in will cause it to run hotter, emit more light, but shorten lifespan considerably. With a constant current driver, the circuit should be switched off frequently in order for the LED to cool down. 

Then you have the risk when you switch on again..... 

Small LED's run at lower than 12vDC voltages.  They are diodes, a diode is an electronic component that only allows electrons to flow thru in one direction.  Initially that was their primary function, so they were an integral component in any circuit filtering AC and delivering DC electricity.  Light emitting diodes were discovered by accident when it was noticed that diodes glowed when they got hot in a radio transmitter, back in 1907.

Basically what is happening is that a "toll" of a photon is emitted when an electron goes thru the gate(diode)

So, I recommend rather that constant voltage be used to drive LED's and then a simple resistor can be used to lower this voltage to the LED's spec.  This way you can actually drive the LED at about 90% current which will cause it to loose only about 5% of light output, but it will run much cooler and for a lot longer.  Constant voltage drivers, e.g. switch mode power supplies, are much more tolerant of varying input voltages, which is also important for protecting electronic equipment on an unstable or varying grid supply which we often have in Africa.

Earth Power's bargin box contains going out of stock items that have been reduced to clear.

Please browse over to our led section to see what is currently in our bargin box section.

New 2kw and 3kw cast aluminum wind turbine

The rear tail could autofurl  to protect the wind turbine

against high wind speed.

During periods of high wind speeds the AutoFurl system will automatically protect the wind turbine. When furled, the power output of the turbine will be significantly reduced. In winds between 15 m/s and 25 m/s it is normal for the turbine to repeatedly furl, unfurl and then furl again. In winds above 25 m/s the turbine should remain continuously furled.
AutoFurl is a simple and elegant method of providing high wind speed protection. The AutoFurl system is based on aerodynamic forces on the rotor, gravity, and the carefully engineered geometry of the wind turbine. The aerodynamic forces acting on the blades cause a thrust force pushing back on the rotor. This force increases with increasing wind speeds.
The thrust force acts through the centerline of the rotor, which is offset from the centerline of the tower pivot axis (yaw axis). Therefore, the thrust force on the rotor is always trying to push the rotor over to the side, away from the wind.
But the rotor is kept facing into the wind at speeds up to ~ 15 m/s by the wind turbine's tail assembly. The tail, in turn, is kept straight by its own weight because its pivot at the back of the nacelle is inclined. So the weight of the tail holds it against a rubber bumper and the tail holds the rotor into the wind.
The AutoFurl system is completely passive, so it is very reliable and since there are no wear points, like in a mechanical brake system, it is very robust.

NEW 2KW SPEC

NEW 3KW SPEC