Frequently Asked Questions (FAQ)
What is colour temperature?
Colour temperature is a characteristic of visible light, and refers to the apparent colour or hue of the light emitted from a bulb. The value of the colour temperature is expressed in Kelvins (K). Bulbs typically range from around 2400K to 6500K. The lower values indicate a "warmer" hue, with the light noticeably shifted to the yellow end of the colour spectrum. Higher K values will appear "cooler" or bluer. Mid-range K values are closest to a neutral, plain white colour.
Bulb manufacturers often use descriptive names to indicate colour temperatures, but as there is no official standard, this oftentimes confuses the issue, since different manufacturers might use different names for similar colours.... or similar names for different colours. Most Glenergy-brand compact fluorescent (CFL), cold cathode fluorescent (CCFL) and light-emitting diode (LED) bulb models are available in 3 different colour temperatures. We use the descriptive names that seem to be most common in the marketplace.
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| 2700 |
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| 4200 |
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| 6500 |
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It's important to note that colour temperature does not affect brightness, or total light output from a bulb. In fact, a 2700K bulb will emit the same amount of light as a 6400K bulb of the same wattage. The cooler colour temperatures, however, are often perceived as "brighter" than the warmer tones because illuminated objects tend to stand out more ... colours appear more vibrant under the cooler light tones. The choice of colour temperature can be based on intended usage or location of the light, but it is largely a matter of personal preference.
When should I use DC lighting instead of AC?
Whether to use some DC (direct current--straight from the batteries) loads or not will depend upon preference as well as upon system size. Even the most efficient inverters are not 100% efficient at converting battery-stored energy into AC (alternating current, 110V--like 'normal' electricity at home) current, so there is some value in any load that does not need to go through the inverter, and even more if the combined DC loads allow purchase of a smaller inverter for less money. So, in small cottage systems, particularly where lighting is a large fraction of the anticipated electrical load, it often makes sense to use 12 V lighting. In larger systems where the building is wired for AC, and where a good quality, high efficiency sine wave inverter is used, it is likely better to use AC lighting as well.
When, where, and why should rechargeable batteries be used?
When? Just about any time batteries are used. The more a battery-powered device is used, the better the argument for using rechargeable batteries becomes. Where? In just about any device or gadget that requires consumer batteries for operation: Games, MP3 players, toys, GPS units, flashlights, tools, etc. .... the list is almost endless. And finally, Why? Convenience, economics, and environmental responsibility.
Rechargeable batteries simply make sense. Battery technology has evolved considerably over the last few years. Today's consumer rechargeable cells use primarily Nickel-Metal Hydride (NiMH); these new generation batteries perform better: they can be recharged more often and have greater storage capacity.
Glenergy carries a full line of rechargeable batteries ranging in size from AAA to D cells? The storage capacities of our cells exceed those of most "store-bought" brands. We also carry a variety of chargers that will charge your batteries either from an AC source (home power), or a 12V source (batteries, for off-grid consumers).
Let's look at that Why? question one more time: With a good stock of rechargeable batteries on hand, never worry about being stuck without batteries again ... convenience. Rechargeable batteries and a decent charger will cost a little more up front than single-use batteries, but by the 13th recharge, they will have paid for themselves. Now you can recharge almost 500 more times .... economy. Finally, every one of your 500 or so recharge cycles equals one less set of disposables being discarded ... how can you not feel great about that environmentally responsible contribution? Even better, every rechargeable battery that we sell is also recyclable--unlike all disposable batteries (most of which are considered hazardous waste).
Talk to a Glenergy representative today about our great prices and broad selection of chargers and batteries.
What about the efficiency of LEDs? Are white LEDs 10 times as efficient as 'regular' bulbs?
The inherent efficiency of light emitting diodes (LEDs) is somewhat better than that of incandescent bulbs, and is improving steadily--sometimes with pretty big gains. High-power LEDs from Luxeon and others are making application such as sign lighting more accessible. However, white LEDs do not enjoy the advantages in overall lighting effectiveness that coloured LEDs have in coloured light applications when compared with incandescent bulbs.
In coloured light applications such as red traffic lights, we can use a white-emitting incandescent bulb and a red lens, or an array of red-emitting diodes. With the incandescent approach, almost 90% of the light that is produced is not red and is wasted because it does not get through the lens, while the LED emits only red. So, the LED is effectively 10 times as 'efficient' as the incandescent approach. Similarly, with other colours in their own applications. This effect is not seen in white light applications because almost all of the light from the incandescent bulbs is white and none is lost to a colour filter.
White LEDs are nonetheless very well suited for task lighting (reading, sewing, bench work, hobbies) and for solar applications where minimal energy consumption is a real concern, since they can provide meaningful light with as little as 1 Watt of power consumption. The very best white LEDs on the market, and the most expensive, are now claiming 50 lumens per Watt or more, and those at 25 or so lumens per Watt are available at affordable prices from a range of worldwide sources. Note that small compact fluorescent bulbs are typically in the 50-60 lumens per Watt range while larger ones can be as much as 80 lumens per Watt.