E-News Issue #38
PV Hook up Wire
We now sell a special PV hook up cable. It is 4 sq mm twin with a special UV rated sheathing around it. This means it does not have to go in conduit. The wholesale price is $4 / m plus GST.
While it sounds expensive it more than pays for itself in the saving of conduit, 2 conduit adaptors and labour. It is designed to fit through the cable glands which come with the Photowatt modules.
We have good stock of most items including solar panels. However, as Christmas approaches we are expecting another rush, so any advance notice you can give us of your requirements would be greatly appreciated.
This is this month's feature article. Lighting is a 'personal' issue. Over the years, I've learned that what is attractive to some is ugly to others; what is light to someone is considered dull by someone else.
The effectiveness of a light also depends on several other factors:
- How close the light is to the area to be lit
- The colour of the walls etc - light shiny colours reflect light; dull dark ones absorb it.
- Diffusers and shades over the light
- Reflectors to direct the light
- Your age (as you get older, you tend to need brighter lights to read by etc.)
When I'm serving people in our shop who want to fit out a whole house, I often suggest they first purchase a few different ones to try out. They can then see which ones best suit their requirements.
I sometimes surprise customers when I tell them they should have a lot of lights for a solar system. This is different from suggesting they should all be on for lengthy periods! You need to look at overall efficiency. So having a low and a high wattage light for the same area means you can use the lower one when you don't need a bright light. In general terms, dimmers are not recommended for most types of lights.
Task lighting is a concept whereby you only light up the area you need. For example why use a 100W to light a whole room when a 20W desk lamp will do the job? - Try and bring your lights reasonably close to where you need them. If your ceiling is high (e.g. cathedral style) suspend your light lower down closer to where you require it. Use a reflector type shade to direct the light downwards.
Diffusers over fluoro lights make them look nicer. However, they can restrict some of the light output, they can often collect bugs inside and in tropical climates they can decrease light output by up to 20% by causing the tube to overheat.
For outdoor lighting consider the use of PIR motion detectors to turn the light on and off automatically (usually adjustable between 1 - 10 minutes). Delay switches can turn off lights, in say public toilets, several minutes after being switched on (so they don't get left on all night).
We sell 4 main types of lights. Listed in order of decreasing efficiency, there are LED, Fluoro, Halogen and Incandescent lights.
These are the most efficient light we sell. While they are relatively expensive, they are very robust as they do not have a filament.
We sell two types of LED lights. Both units are fitted into an Australian type standard bayonet cap (BC) adapter which fits into standard BC type lamp holders.
The night light uses a single super bright white LED. It has an emission colour temperature of 8000K which is a rather blue colour. It is rated at 6000mCd and draws 20mA on either 12 or 24V. It has a rated lifespan of 100,000 hours. In practical terms, I would suggest that it is about as bright as a candle.
The Rainbow LED light has 15 LED's of various colours (green, orange and red). They draw 120mA and are suitable for a party, TV or background light.
However, we would not normally recommend them as being suitable for reading since they do not give a natural colour rendition and they do not give a lot of light. However, they are efficient as they use less then 1% of the power of a 20W light.
These are some 3 times more efficient than an incandescent bulb - eg: a 20W fluoro is roughly 3 times brighter then a 20W bulb. Today most modern fluoros do not emit that rather cold blue light that was the norm 10 - 20 years ago. Most types, particularly the more modern PL type (often U-shaped) come in a variety of warm colours. We generally suggest using fluoros for most of your lighting requirements due to their high efficiency. Their light output decreases after several thousand hours of use when they should be replaced.
These bulbs use special materials which enables them to be run at higher temperatures than a standard incandescent bulb. They are about 30% more efficient than a standard incandescent bulb and produce a whiter light similar to daylight. For this reason they are often used in art galleries and jewellery shops to bring out their 'natural colours'. They are long lasting, usually rated at 2000 hours. Dichroic halogens have a special reflector around the bulb.
These are the cheapest and least efficient type of bulb. Examples are your standard 230V light bulb and 12V automotive globes. They produce a very yellow light and are usually rated for 1000 hour life span.
Besides the four main types of lights, there are several other types with specialised applications such as sheet lights, factory lighting etc. Please feel free to contact us for assistance in designing your lighting needs.
That's all for this month.
Cheers from Dave and all the RPC crew.
Dave Lambert (Director)
- Issue #92 - 06/12/2005
- Issue #91 - 15/11/2005
- Issue #90 - 20/10/2005
- Issue #89 - 29/09/2005
- Issue #88 - 01/09/2005
- Issue #87 - 29/07/2005
- Issue #86 - 04/07/2005
- Issue #85 - 03/06/2005
- Issue #84 - 05/05/2005
- Issue #83 - 01/04/2005
- Issue #82 - 03/03/2005
- Issue #81 - 23/02/2005
- Issue #80 - 02/02/2005
- Issue #79 - 05/01/2005