Jan 20 2011

How many watts does my solar panel need to be if I am running lights only at night?

Posted by As Seen On Tv in As-Seen-On-Tv
Tags: , , , , , , , , | 2 Comments

Question by Carrie: How many watts does my solar panel need to be if I am running lights only at night?
I want to use 12vDc rope lighting that is 3 watts per foot and i am looking to use approx 64 ft of light. I am probably only going to have the lights on for 3-4 hours at night. I will be running the lights off a 12 volt car battery. What wattage will my solar panel need to be to recharge the battery during the day. I would appreciate any help, Thank You! I am also looking at led lighting that is only 0.8 watt per foot.

Best answer:

Answer by mike1942f
Your numbers give 172 watts which at 12 volts is 14.33 amps. In theory, you would need to have a 57 amp hour battery, but auto batteries hate being completely discharged so you would either need a more expensive deep discharge battery, or a much higher amp-hour car battery or a cut off circuit to cut off the power when it dropped to about 10 volts (or both)
You didn’t say where you are, which is critical for the amount of light you get, especially if you are running this through the short dark days of winter. If you can only get 4 hours of good sunlight when you want 4 hours of night light, then you need at least 200 watts of solar supplied power and enough battery capacity to hold it from high to low voltage limits.

Give your answer to this question below!

Tags: , , , , , , , ,

2 Responses to “How many watts does my solar panel need to be if I am running lights only at night?”

  1. Diana Says:
    January 20th, 2011 at 9:54 am

    you should find some answers here

    http://www.google.ca/search?hl=en&source=hp&q=solar+power+calculator&meta=&aq=0&oq=solar+power+calcula

    also here

    http://www.google.ca/search?hl=en&source=hp&q=solar+power+calculator+software&meta=&aq=4&oq=solar+power+calcula

    D

  2. New Says:
    January 20th, 2011 at 10:42 am

    You can use a 1-2 160W solar panels costing less than $ 200.

Leave a Reply

You must be logged in to post a comment.