Solar panel for outdoor lights


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Old 04-27-21, 12:22 PM
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Solar panel for outdoor lights

Existing security lights located at corners seem to be inadequate. I don't know how to neatly run an extension from a corner electrical box to a between-corner location. I wonder if solar is the way to go. One big question I have is about panel output. Can I use 40 volt panel to charge 12v battery? Poor efficiency? I will use mppt charge controller. Thank you.
 
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Old 04-28-21, 10:06 AM
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As long as the MPPT controller is rated for a higher input voltage than the max open-circuit voltage of the solar panel, it will work and be efficient. For example, my Renogy 100w "12v" panel puts out 21.5 volts open-circuit. So I would use a controller rated at 30 or 40 v, just to be sure.

Of course, there are motion-activated solar lights with their own built-in panels. I have several, they work fine, but not suitable if you want to leave them on all night.
 
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Old 04-28-21, 10:06 AM
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How much light do you need? I've found motion sensor solar lights work well in certain cases, where you need some decent light - but not "light up a basketball court" level of light - and goes on a handful of times during the night.

Something like this. Not recommending this one in particular, but this style.
https://www.amazon.com/Westinghouse-.../dp/B07N8Q96KH

If you're looking for lights that are on all night, you probably want to be using a 120v wired light in my opinion at least.
 
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Old 04-28-21, 11:58 AM
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I found a cracked 400 watt solar panel on offerup cheaper than new 100 W. Thank you for the explanation, MPPT Input V > Panel Open Circuit V.

I don't need the basketball court brightness, just to fill in between 2 corner lights that do not see each other. I will also consider the motion sensored solar lights. Thank you.

 
 

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