Low energy and alternative energy lighting.
An important consideration in alternatve energy systems is low power lighting. Standard filament bulbs produce a lot of heat, which is usually a waste of energy. Two alternatives, CFL and LED are described below.
A 12V DC CFL bulb
The circuit from inside a blown 240V CFL.
Note the heat damage, and the number of components..
CFL bulbs (compact flourescent) have received a lot of media attention, and have become a popular way of reducing costs, electricity consumption and carbon footprint.They generally claim to use 20% of the energy (although strangely some manufactures quote this figure as 25%) as compared to filament bulbs, to last longer and are also available in 12V DC versions, seemingly ideal for wind and solar battery systems. However, there are some disturbing facts about CFLs that are less generally known.
As an example, here is the package from a Eurolux 12V DC CFL bulb. It does NOT mention mecury, give instructions for clean up procedures or warn about overheating in enclosed fixtures. Once you have opened (and presumably purchased) the Eurolux bulb, an inner flap contains the slightly obscure warning 'Not dimmable' in four (European) languages. In my opinion, this is a clear case of deceptive packaging/advertising. The Osram package is a little better, in that the phrase about dimming is visible without actually opening the pack.
Local distributors seem to be making no effort to offer safe disposal or recycling facilities.
Click on either package to see a larger image.
The Eurolux pack is also interesting in that omits any mention of the manufacturer, their address, or the address of the distributor.
Does this comply with South African packaging and labelling laws I wonder?
LED lights last over 100 times longer than filament bulbs. They also produce almost no heat, and since they are solid, withstand vibration and shocks. LEDs can run off batteries without the need for a complex circuit, making them ideal for battery, solar or wind power systems. They can also be dimmed.
Individual LEDs are available in a variety of colours, and draw between 3mA and 50mA.
On the right is a standard downlight fitting with 48 LEDs. This draws 90mA at 12V, and produces white light with a greenish tinge. A filament bulb of the same size draws 4000mA! (over forty times more), although the filament bulb is much brighter.
On the left is 1.5watt 24 LED buld in the same housing. It is considerably brighter, twice the price, and produces a whiter light with a very slight blue tinge.
A stainless steel fixture with a 38 LED globe. It draws 100mA at 12V.
A disadvantage is that LED lights are currently expensive, although the prices are falling. Also, because of the limited market, it is sometimes hard to find the desired colour - some can produce a 'cold' bluish light, and some a greenish tinged light. Technology and availability is constantly improving however, and LEDs seem to be the lighting of the future.
UPDATE: These are the latest LEDs. They are amazingly powerful, and use very little current, producing close to 100 lumens per watt of power consumed. The rigid strips are about 400mm long and use 2W. It is also available in flexible stick on strip in lengths up to 6 metres.
They run on 12V, so can be connected directly to a 12V battery, or any 12V supply connected to the mains. Two in series can be connected to a 24V system. They can be bought online here.