# solar ligths



## pete (Jan 2, 2008)

I have a question about solar lights. Are there brighter ones than other. What i mean is do they come in different watts or brightnest. Thanks for any help.


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## East Broad Top (Dec 29, 2007)

There are some that I've seen that claim to be "50% brighter" than others, but what does that mean? There's no rating that measures the amount of light given off like you'd find in light bulbs. I've used a handful of different ones, and all seem to be about equal--not that it matters to me since I gut them and use my own LEDs. 

Later, 

K


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## Tom Parkins (Jan 2, 2008)

First I assume that you are referring to solar path lights??? There is a difference in light intensity. It is often very difficult to find accurate information, but usually somewhere buried in the specifications it will describe the light intensity. This is sometimes reported in Lumens (the same as light bulbs). But there is no consistency. 50% brighter could refer to it is 50% brighter than the dollar store model which is usually a single LED. Or it could mean that it is 50% brighter than there previous model. 

Typically a basic solar path light is 1.2 Lumens for a single LED. Double LEDs may be 2.4 Lumens.. But as LEDs get brighter some path lights now put out 30 Lumens. Of course the cost go up, and perhaps the power consumption. For comparison a 40 watt incandescent light bulb on 110volts puts out about 450 Lumens and a standard 100 watt bulb about 1600 lumens. 


Some LED path lights are rated in mcd, milli candela. 1000 mcd is one candela or about the light output of one candle. Typical single white LED output is about 4500 mcd or 4.5 candela. BUT. LEDs also depend on the angle of the output, so it is not always about total mcds. Now you add in the color (temperature) factor and take two LEDs with the same mcd and angle. But one may still appear brighter because of difference in color. Confused? Try explaining this to the average person at Home Depot. Usually you will just see a sign that says Good Better Best. 

Bottom line..... Yes there is a difference.



Hope this helps just a little. My planning period is over. Let me now return to the classroom and teach the fundamentals of physics to teenagers so that they can look smart when they go to Home Depot. 

Tom


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