What is an LED?
LED stands for Light Emitting Diode. Simply put, it's a special piece of electronic hardware that turns electrical current into light. A key advantage of LED lighting is its high efficiency, as measured by its light output per unit power input. Another advantage is the fact that LED's are "Solid-State" devices. This means that they are based on semiconductors like the ‘chip’ in a computer, and contain no moving parts. Because LED's are solid-state devices, they have much longer service lives than traditional bulbs (halogen) or bulb/ballast units (HID).
Yet another bonus with LED's is their ability to withstand external shock, making them ideal for cycling and other outdoor activities. The fact that they light up quickly and have virtually no warm-up cycle is also helpful.
What’s a Lumen?
Short answer, a lumen is the unit measure of the luminous intensity of a light source. The more lumens, the brighter the light.
You want the long answer? Okay, here you go: Luminous flux is the measure of the perceived power of light. A lumen is the SI unit of luminous flux. One lumen is defined as the amount of light produced by a light source that emits one candela of luminous intensity over a specified angle.
Previously, many light manufacturers listed "output" in watts, which is incorrect. The Watt is a measurement of power consumption, not light output. For example, a 1-Watt LED can produce 120 lumens of light because of the inherent efficiency of LED's. To get the same output from an incandescent bulb (like the ones that you use in your lamps at home), you'd need to use a 4-Watt bulb. So 1 Watt for LED's versus 4 Watts for Halogen—but still the same 120 lumens of output. You can see how people were confused. We list our power in lumens to give you the clearest "apples-to-apples" comparison possible.
The best LEDs can produce 120 lumens at 350mA, or about 1W. Halogen bulbs (optimistically) produce about 30 lumens per Watt. This means that a Halogen bulb would require 4 Watts to produce 120 lumens, consuming 4 times the battery power of the LED!
What is Lithium-ion?
Li-ion batteries are lighter than equivalent NiMH batteries—often much lighter. They also have a much higher energy density than similarly sized NiMH cells. However, Li-ion batteries are more expensive due to the Lithium compounds that are used in their construction and they must be designed with an electronic circuit to carefully monitor charging. The service life of a Li-ion cell is shorter than that of NiMH, and will provide approximately half the number of charge cycles as a NiMH battery (typically 500 charge cycles for Li-ion vs. 1000 for NiMH). Our Multi-Chemistry Smart Charger and dedicated Lithium Ion Smart Chargers control Li-ion charging with a protocol known as constant-current, constant voltage. The charger supplies a constant amount of current until the battery is charged to about 80% of capacity, and then changes to supply a constant voltage for the last 20% of capacity as the current decreses. This is the charging method required for proper, safe charging of Lithium Ion batteries.
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