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How do you use a solar panel to light a 10w light bulb at night? And what kind of a solar panel would I need? Answered

I want to make my own solar panel (a small one) for a school project, but I also want it to be useful for after the project as well. I need a small light to light something outside, but at night (because, obviously, I can see during the day). So apparently you need a battery to store the energy during the day, and a charge controller is really important. I've found a lot of useful sites and videos (and instructables) that show how to make solar panels, and a few that show how to connect the solar panel directly to a light bulb, but I can't seem to find anything that clearly explains the battery and charge controller part.

Please note that I know nothing about the technology of solar panels, watts, volts, etc., and have never taken apart or made even a simple electronic device of any sort. The most experience I had with this stuff was when I made a small circuit with a light bulb, battery, and alligator clips sometime around the sixth grade, but I have no idea how all that works and all the numbers that you need to keep in mind (I did learn the basics a couple years back, but I've forgotten everything), so when I find brief explanations online that say you need a battery, charge controller, and you need to somehow calculate the correct capacity and voltage, I'm totally lost.

Can someone please help me out and explain? Or at least provide a useful link or something? I've scoured the Internet, trust me. Unfortunately, I was unable to find anything clear or something in a "How-to" format.

Also, I'm flexible on the 10w thing. A 10w light bulb was just the lowest I could find and I thought the lower the better.

So what kind of a battery and solar panel (how many watts/volts, etc) would I need? Low cost is ideal.



Answer 3 years ago


Take a look at some of the projects here on the right for some clues. Its not our job to teach you basic electricity. The idea of being taught something is to remember it so you can use it again.

What kind of "lamp" were you thinking of ? An LED ? They come in MUCH smaller sizes than 10W.

You don't "need" a charge controller, nice, but not strictly necessary if you get the rest of the things balanced properly, like output power and voltage.

I'm not looking for a full on explanation about electricity, and I apologize if I sounded like it; for now, I don't need to understand about watts, currents, volts, etc., I just want to know how to hook up a solar panel to a light bulb and have it light at night. Many guides on how to build solar panels don't explain the science of it, they just say "connect this with that," "cut this and do this," and, "put the red wire there," etc. That's more of what I'm looking for.

Can I just get a 10w solar panel to power a 10w bulb? Does voltage matter (i.e. do all 10w solar panels have the same voltage anyway?)? And then do I just need a battery that has the same amount of voltage as the solar panel (disregarding the light bulb's voltage)? And how could I set this all up?

Well, it needs to be pretty bright; do you have a particular recommendation? I just looked again on the website of a store that's nearby and I found a 7.5W LED bulb, but it's over $20, which is twice the price of the 10w bulb I initially found; but it's not an LED. Are LEDs better?

No, a 10 W panel could have virtually any voltage, which is why I asked about the bulb. LEDs are what you want to use. LEDs are much more efficient and lot brighter than a conventional filament lamp, which you would have found out, from a couple of minutes googling.

The words "Solar LED" and searching instructables seems to me to yield several hundred great little projects to explain it.

And yes, you really DO need to understand voltage, current and power to make sense of it.