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Lets see how smart everyone is----trying to build outdoor led wall washer Answered

I am trying to build an outdoor led based wall washer, the idea is to light a wall (from the ground up) using a golf cart battery and led lights. Now here is the tricky part the wall is 45 feet tall, and 40 feet wide. I have to admit that projecting this amount of light on such a large space has thus far been beyond my ability, if anyone has any ideas I would appreciate it.



10 years ago

yes the light needs to be on all night, the idea would be to use one or multiple batteries to give the panel enough time to charge the previous batteries, we would use one 80 wait solar panel whose measurements are 47in.L x 21in.W x 1 1/2in.D.

Anyone know if that is 80 Watt averaged over a typical day, or 80 Watt peak power - at mid-day in full sunlight? Let's assume for now that you get 40 Watt average during the day. LEDs are 4-5 times more efficient than your typical incandescent light bulbs. Do you feel you could light that surface area sufficiently using 4-5 40W lightbulbs?


10 years ago

You're going to have to give us some more parameters here - what capacity does the golf cart battery have, how bright does the wall need to be illuminated, and does it need to be white light? (And does it need to be LED-based? Sodium vapor lamp are far more efficient.)

Here are the details; we want to create a system that can run the light during the night and then self recharge with a solar panel during the day. The wall will have painted writing on it so we want the wall to be light bright enough to read the writing. We want to use a led system because otherwise the power draw will be too much. We are looking at deep cycle batteries, with between 85-115 amp hours, how many batteries and the amps will depend upon the draw of the system. A white or bright color would be ideal because that would make the writing as bright as possible, but it does not matter. Our main goal is to light the entire wall 45 feet high by 40 feet wide.

Does the light need to be on the whole night? And how much area can you afford to devote to solar cells...

A few facts of life: Commercial solar cells typically convert around 12% of sunlight into electrical energy. And some of the best white LEDs have a luminous efficiency (electrical energy converted into visible light) of around 10%.

So if you build a 45 feet high by 40 feet wide solar panel, to collect energy to light your 45 feet high by 40 feet wide wall, at best you could only get about 1% of the average daylight intensity. Which might be enough - daylight is *really* bright. But I doubt you'd be willing to put up with a 45x40' solar panel...