High Powered LED Solar Lighting System




About: I used to teach middle school science, but now I run my own online educational science website. I spend my days designing new projects for students and Makers to put together.

While I love making proof of concept solar projects, or solar projects that I might use if the world comes to an end, I prefer to make solar projects that are useful in my day to day life. (I love my solar FM radio, but I've never had the need to use it in an emergency situation)

This past summer my father had been complaining about installing a lighting system for the back of his yard. The big issue being that he hates running wire 100 yards just to get three lights to turn on at night. Plus, being the over achiever that he is, he decided to bury the wires so that he wouldn't run over them with the lawn mower. This is when I stepped in.

I decided to make a high powered solar lighting system so no wires would ever need to be run to the back of the yard. Ever.

Oh, and I'm not talking about a few little wussy LEDs inside of a jar, I'm talking some high powered 3 watt LEDs inside real metal lighting enclosures. Ones that will probably attract every moth for ten miles. (And in defense of LEDs in jars, I happen to have 12 of those on the deck of my apartment. A couple slowly pulsing in and out.)

So for your enjoyment, here is a quick, easy, and inexpensive guide to making a high powered solar lighting system.

(If you like my project, vote for it in the Off The Grid Contest here at instructables, I'm the first entry. Seriously. A vote for me will bring you instant karma and a warm fuzzy feeling. WARNING: Warm fuzzy feeling may in fact be low levels of radiation. Seek medical help.)

If you're looking to make a smaller solar project, check out our basic Solar USB 2.0 Kit or the more rugged Lithium Heavy Duty 2.0 Kit.

Step 1: What You'll Need

To be honest, we're pretty much just hacking a cheap lighting system into a solar lighting system. Most of the parts we will need come preassembled. We're mostly just wiring things up. The nice part about that is the fact that we only have to do a little soldering.

Cheap Lighting System (With 2 or more metal "heads")
Heavy Duty Outdoors Wire
High Powered LEDs (1 Watt or 3 Watt depending on your needs)
High Powered LED Driver
Heat Sinks
18V or better Solar Panel
12V Solar Charge Controller
12V Battery
Plastic Container
Cable Clamp
Terminal Strip

Dark Detecting Circuit:
PNP Transistor (I used a TIP42)
A Prototyping Board
10,000 Ohm Resistor
1N4001 Diode

Soldering Iron
Helping Hand
Screw Drivers
Silicon Calk
Wire Stripper and Cutter

Cost: $75 - 100
Time: 2 - 3 Hours

I bought all the electronics off of eBay on the cheap. The hardware parts I bought from a local hardware store. The total cost of this project was in the range of $75 - 100. Not overly expensive, but much cheaper than any store bought high powered solar lighting system. Plus a whole lot more powerful. I also bought a more expensive driver than I needed in case I wanted extra functions, you could easly shave $10 off the project by getting a cheaper one.

The majority of your time will be spent trying to figure out how to run wires into and out of things. The amount of real "making" work is rather small.

Step 2: High Powered LEDs

High powered LEDs are not like your regular LEDs. They use a lot of current and put out a lot of heat. They are, however, quite cheap. I bought mine on eBay for a few dollars. I went with 3 Watt LEDs because... well... I like the power. Most people would be happy with some 1 Watt LEDs.

One thing to keep in mind is that these LEDs need a "driver." This is a circuit designed to regulate current so you don't blow out your LED. Plus you can use any LED color type without having to switch out resistors. Quite handy. When buying a LED Driver make sure you're getting one with the same power rating as the LED you want to use. My driver can handle up to 10 Watts, which is perfect for running two 3 watt LEDs off of 12V. (Or so says the instruction PDF file.)

In the picture above I'm using the driver on the left. It can handle 10 Watts of output. The one on the right you can use to power a single 1 Watt LED. As you can probably guess the one on the left is more expensive. I choose to get this more expensive driver for it's added features, and you can easily make things cheaper by going with a more "standard" driver.

(Plus if you're really feeling adventurous, you can hook up a micro controller to the LED Driver to do some crazy effects. Oh yes. Arduino power your LED lighting system. Which I might do. Just because I can. Have it pulse in and out or do strobes at a certain time...)

Step 3: Take Apart the Lighting System

This lighting system was bought on clearance, so I had no issues gutting it.

First cut the wires going into the housing.

Then remove the various electronics on the inside. In this case it's just the connector that would hook up the regular light bulb.

Just cut and pull.

Step 4: Thread the Wire

Now take your new outdoors wire and thread it back along the same path.

I had to use some needle nosed pliers to help pull it through at one point. Not too tough to do, but slightly awkward.

Make sure to leave a good amount of wire sticking out the top so we can solder.

(Make sure you thread it in the EXACT same way as the original wire. While this may not always be possible, it is the most simple solution. Otherwise drill a hole in the side and later seal it up with some calk.)

Step 5: Solder Your LED

Strip the ends of the wire.

Use a helping hand, or some other holder, to grip the LED.

Now solder one wire onto a + tab and one onto a - tab.

After I soldered the LED I also put a heat sink on the bottom of the LED. These guys can get hot, and since we're in a mostly enclosed space I don't want to take any risks.

Step 6: Reassemble

Well now you're going to want to pull the extra wire back through the housing. Take this time to situate your LED.

(I honestly just wedged it in there. No need for extra adhesive or parts. If you do try and use something, make sure it's heat resistant.)

Reassemble your little lighting unit.

Ta da! You have a high powered LED inside of a classy metal outside lighting structure!

Now go do this one or two more times.

I made two heads for this project, but I'll eventually make a third as my driver can handle it.

Step 7: Create the Enclosure

As this is going to be outside I wanted to make a nice safe enclosure to handle Wisconsin weather.

I took a plain plastic tub and modified it a bit using a cable clamp. More or less a big screw in system that latches onto wires to hold them in place. I got this from a local hardware store, and they had several types.

To make the hole in the side of the tub I chose to use an old soldering iron and melt a hole. Using a drill will work for some people if their enclosure can handle it. I have bad luck with drilling plastic and I don't want any cracks.

Once the hole was the right size for the clamp I twisted it into place. I also added in a rubber washer to help protect against water. Once everything was in place, I used some silicon caulk to further water protect it all. (Yes, when you run wires through there will still be open space. Try running the wires through a couple of rubber washer, and use those to seal up the holes. That and more caulk if you want things to be super permanent.)

If you're worried about water coming in the top, get some rubber and line the inside of the lid. A cheap and easy O-Ring also works. You could also add a line of caulk as well for similar protection. If you want to make things very easy for yourself, find a food container that already has an O-Ring built in, though they can get expensive at the size we're using.

Step 8: Wire Up Everything Else

From here on out, we're just screwing wires into place. The hard work is over.

I cut some wire and attached it to a terminal connector for use with my battery. You may wish to do the same, or just use some alligator clips.

I then connected the Positive and Negative tabs on my battery to the B+ and B- terminals on the Charge Controller. As my charge controller uses screw clamps, this was easy.

Then I took some more wire and hooked it up to the L+ and L- on the charge controller. These are the "Load" terminals that supply power to whatever it is you're trying to run.

Those then connected to the V+ and Ground (Negative) screw terminals on my LED Driver.

Told you the hard stuff was done.

Step 9: Wiring Up the LEDs

To wire in the LEDs we're going to do the exact same type of connecting, but using a terminal strip.

Take the Positive wire from one of your LEDs and hook it into the LED Driver + Out Clamp. (If you don't know which is positive and which is negative, grab a multimeter and do a quick test.)

The Negative wire from that LED needs to go into one of the Terminal Strip holes.

Take the Positive wire off the other LED, and put it in the same terminal strip hole.

The Negative wire you have left over goes into the LED Driver completing the circuit.

if you didn't catch what we're doing, we're hooking things up in a Series. Positive to Negative, Positive to Negative. If we wanted to we could add more LEDs into the mix doing the same pattern. My driver can do 10 watts, which means if I provide a 24V power input I could easily control ten 1 Watt LEDs. Though I'm just going to do 2 or 3 of my 3 Watt LEDs.

Step 10: Test It Out

Well at this point you're either being blinded by LEDs or you messed up somewhere. Hopefully you're being blinded.

Step 11: Put Everything Into the Box

Well now that you know how everything hooks together, it's time to wire up the box. (Which means you're going to have to unscrew all your wires. But don't complain, it's an easy task!)

Run all your wires into the box. The two LEDs and the Solar Panel.

Now reconnect everything together. Does it work?

(Hook the Solar Panel into the Solar Charger Controller by screwing the wires into the S+ and S- clamps.)

Step 12: Enjoy!

Well that's it. You should be getting a whole lot of light coming at you. Stick it outside and enjoy. You now have a great lighting system that looks classy and will provide a lot of light.

You can use this same design with any color of LED. I enjoy the cool refreshing choice of "white" light.

You could also modify this design and use it for lights inside your home or on your deck. Same idea, but add a switch into the mix.

If you're an overachiever you may wish to go to my "final final" step and make yourself a dark detecting circuit. It only takes a couple of minutes and makes you seem all the more awesome to the neighbors.

Step 13: But Hey Now...

So many of you are probably wondering why I've not talked about darkness detecting. Meaning the fact that this system is just always "on", which is a waste of power and very very annoying.

To do this all you need is a strong PNP transistor, a 10K Ohm resistor, and a diode.

Check out the circuit diagram above to see what I mean.

What we're doing is using the transistor as a "gateway". When the transistor is getting power from the solar cell (meaning day time) the "gate" is closed. At night time when there is no power coming from the solar panel, the "gate" opens and power goes to the LEDs.

More or less we're using a system similar to how regular small garden lights work, and all for the cost of a PNP transistor and a resistor.

The key is finding a strong enough transistor. A standard 2N3904 will NOT work. You'll nee something that can handle higher voltages and a higher current. As my solar panel is 21V at 0.6amp I'm using a transistor with a bigger kick.

Another option would be to use a Microcontroller (such as an Arduino) to control the LED Driver. The driver I have has a PWM port. It would be easy to wire an Arduino into the setup to act as the darkness detector. Though to be honest that is a bit of an overkill for this project. You could also then power the Arduino via the 12V battery, and in my case I could use the built in USB ports on the charge controller. (I may in the future, but thats a different guide all together.)

Step 14: Make a Dark Detecting Circuit

1N4001 Diode (or something similar)
TIP42 Transistor (or any similar PNP transistor)
10,000Ohm Resistor
A Prototyping Board
(If you have an extra heat sink, use it.)

Soldering Iron
Wire Cutter

All we're doing is soldering on the transistor, resistor, and 3 wires to the prototyping board. The diode we use in conjunction with the solar panel later on.

***Before you do ANYTHING you should locate information about what each leg of your transistor does what. You have a Base, Emitter, and a Collector. Know which one is which. Usually it's on the packaging, otherwise google it.***

Put the transistor in the middle of the board and solder it into place.

Find the Base leg. Put the resistor next to it, and solder the resistor into place. Now connect one leg of the resistor to the Base leg.

Now get your wire. We want to connect one wire to the free end of the resistor, to the Collector leg, and to the Emitter leg.

I also took one of my extra heat sinks and put it on the back of the transistor. While it probably isn't necessary, I might as well.

Step 15: Other Transistor Things...

It's important that you label which leg is which. Seriously. If you don't, you'll end up like my FIRST attempt at this circuit. The one where my transistor sparked and split in two.

Step 16: How to Wire It Into Your System

The last thing to do is break out the screwdriver and wire it into the system. Along with the diode.

Remove the Positive wires of both the solar panel and the LED driver from the Charge Controller. (We're completely getting rid of the positive wire going between the Controller and the Driver and replacing it with this circuit.)

Find the Positive wire coming off your solar panel. Hook it up to the positive leg of your diode. Then put the Negative leg of the diode (it's the one with the black or silver bar on it) into the Positive input of your charge controller.

Take the Base wire from the Dark Detecting Circuit (it's the one with the resistor if you did things correctly) and attach it to the diode at the same point where you attached the solar cell's Positive wire. Or in other words, BEFORE the diode.

Next, take the wire coming off the Emitter leg and put it into the Positive Load spot on your Controller.

Lastly take the Collector wire and put it into the Positive power in clamp of the Driver.

That's it. Turn the solar panel face down and see if the LEDs turn on. Mine did. You can change how "sensitive" this circuit is by changing the value of the resistor in the circuit.

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    24 Discussions


    Question 3 months ago

    As matter of interest, if you run 3x 3W LED's off that 7Ah battery, how long does it actually run before the battery is flat?


    3 years ago

    Does the watt rating of the 10K resistor matter ? 1/4 watt through 2 watt available on Ebay. What would work best ?


    4 years ago on Introduction

    I know this is an old thread, but I am not sure where else to post my question. I acquired an old gas streetlight which I want to install in my front yard. I don't want to run electric for a conversion and gas would not be an option either. Would like to create a nice looking interior light that is solar but I don't want a huge panel sitting on top to ruin the antique fixture. I do not need a tremendous amount of light--maybe equal to a 40-60 watt incandescent? I would like a really nice attractive light similar to a candle or like the gas light looked. I have no idea where to get parts or instructions for this so I came across this thread and joined so I could ask someone to help if they can. I'm looking for something unique and classy to go with the beautiful exterior of this old light. Thanks!


    6 years ago on Introduction

    I have been wracking my brain to work out a system like this. I need some bright light in the driveway and in the back yard. I can easily avoid the weather in both areas by placing the box of tricks under the roof, and the lights on either end of my boat shed, with the solar panel on top of the roof. However, the piddly little garden lights would be useless for my situation. I wonder now if I can become an electrician. At least a hobbyist type. Thanks for this one, it is great.

    1 reply

    Well sweet. I'm glad it came in handy for you. Solar system are rather simple once you learn what everything is and how they interact together. I'm no master electrician, just a simple hobbyist, and learning how to use solar in my projects was the best thing I ever did.


    6 years ago on Introduction

    very interesting I have been doing optics since 92 and wonder if we could talk sometime my name is Mark Zimmerman and I go by the name optichead I need some fine tuning for a new garden system Im at sealwizene@aol.com


    6 years ago on Introduction

    Very well done mate.
    How is the thing holding up?
    I'm worried about the heatsinks on the LEDs (They seem tiny), Are they adequate? or Could we use some interface that enables whole enclosure as an heatsink?

    1 reply

    6 years ago on Step 13

    This would be a great situation to use an ATtiny 85 - small and cheap, it could measure the voltage from the solar panel to do your dark detecting and also control any fancy functions, like fading or blinking. You could also set it up to give full light for the first few hours of darkness (for show) and then just a little light during the rest of the night to find your way around!

    I love the idea of massive, powerful things controlled by little tiny controllers running your home-written firmware, and this is the perfect setup for it - you have a PWM control input, you have +5V and the solar-cell voltage available. All you need is an ATTiny and a breakout board!

    1 reply

    Reply 6 years ago on Step 13

    Oooooo thats an AWESOME idea. I just happen to have a couple of hundred ATtiny85 chips around. I'll have to give it a whirl.



    6 years ago on Step 13

    Another option for the dark detection would be simply to use the PWM pin of your controller with a simple pull down resistor and a low power transistor. Depending on the voltage limits of your controller's PWM pin, you could use essentially the same circuit you did here except the transistor would be feeding the PWM pin instead of the LEDs.

    As a side note, isnt the 2N3904 you mention a NPN transistor? The way your circuit works, a PNP transistor is needed (as you correctly said so in your text and circuit drawing). It might be good to change the reference to the complementary 2N3906 (PNP) or to simply state the it is a NPN. That way, the less knowledgeable that dont need high power are not misled into using a transistor that would not work in this application (NPN would always be on).

    1 reply

    Reply 6 years ago on Step 13

    Doh! You are correct. I did reference the wrong transistor.

    Good call with the PWM pin. I'll give that a try.



    6 years ago on Introduction

    Joshua: OK on your comments, & I certainly appreciate the regulator's function.  With only a dusk-midnight need you may well want to include a simple timer too. How about  using the likes of a PICAXE micro =>   www.picaxe.orcon.net.nz   ?  These are a dream for pre-teens!

    Mmm- given your freezing Wisconsin winters an additional aspect  may relate to lead acid batteries poor performance when cold/chilled. Best wrap up that poor SLA  to keep it cosy!

    Happy to point out this SLA "Gel Cell" source,especially as you're a teacher with (no doubt) a cash strapped budget. Being sealed they present no fume or acid spill concerns of course. Sigh-if only they'd been available when I was younger. Back in my teens I recall rescuing a regular flooded car battery & building it into bench power supply, with resulting sulfuric acid "migration"-argh!

    Discarded SLA batteries are usually just sent for scrap metal, & (even with the present value of lead) only bring in about US$1-$2 each. This may be hardly worthwhile for the security firm to bother with, so you could perhaps even make some science resource "pocket money" by offering to do it for them. Play up your educational needs of course.   Hence rescue quite a swag, use the good ones (or pass to capable  students/friends) & take the really weary ones in for scrap $$ yourself. It sure beats collecting aluminum drink cans.

    Health & Safety ALERT: 12V 7Ah SLAs are VERY energetic & start a fire if shorted, and even jump start a car, or power an e-bike/scooter etc. I once gave a 12V 7Ah SLA to a 12 yo. who'd looked a budding bright spark. Word filtered back to me however that he'd just used it to "make a bomb" by shorting the terminals with a heavy duty cable, to then relish the resulting acrid smoke & fumes as the battery destructed... I now only pass out the smaller 12V 2Ah types when in doubt about the end user's motives.

    Extra:  A simple charge confirmation indicator can be VERY worthwhile too -at the least it confirms connections haven't come adrift or terminals corroded. I've done a bit in the past with FLEDs ( Flashng LEDs) for this in fact (See Instructable => www.instructables.com/id/Single-LED-ammeter-FLED-based/ )  & the attached relates to one a student of mine recently used for a similar (but switched) LED lighting project.

    Stan. - semi-retired  "hands on" educator ( Wellington- NZ)

    2 replies

    Reply 6 years ago on Introduction

    Be darned - I've got this far so may as well also tweak your initial day/night switch! It's possible that a weak but firm pull down may be needed as well in your circuit- refer picture.


    Reply 6 years ago on Introduction

    The addition of a pull down resistor on the transistor's base shouldn't hinder the function of this circuit however it may not be necessary. PV cells loose their voltage during darkness, that is why you need a blocking diode to stop your batteries from discharging through the panel, this lower voltage should in theory be enough to power the transistor.


    6 years ago on Introduction

    By the looks of it I'd guess your solar PV is rated at 10 Watts? Thus with an average of 4 hours bright sun daily the battery will receive approx. half a charge each day. However a 3W LED could be on for 10-12 hours each night, & more in winter. A few days of gloom would mean the battery near drained & it's life possibly greatly reduced!!  With such a lighting load you may hence need a larger PV, or more batteries...

    Handy hint: Check a local security firm for free SLA ( Sealed Lead Acid) "discards". Here in NZ  such contacts supply more than I can handle - they're ideal for my educational work. Such 12V 7Ah batteries are a global standby standard & firms often renew them at critical sites every couple of years to ensure reliability.. In less demanding applications they'll usually still be good for  5-8 years if not allowed to go flat or discharged too deeply.

    FWIW even 20W PVs,c/w inbuilt controller, are often now under US$50 in the right places.

    2 replies

    Reply 6 years ago on Introduction

    Oh, and you don't have to worry about the battery every completely draining! Thats what the solar charge controller is for. When the battery hits a certain "low" voltage the charge controller cuts off the "load." I always recommend people spend the $10-20 for one in order to save their batteries from excess wear and tear.


    Reply 6 years ago on Introduction

    I completely agree. The panel is a 10 Watt panel, and I have a second panel around as well if my father wants more light.

    He mainly wants lighting from dusk until midnight, after that he's asleep and doesn't care how things look.

    I'll look into SLA discards locally, thanks for the hint. That would really bring down the cost of the entire setup.


    6 years ago on Introduction

    Thank you! I did some landscaping last year and have wanted to try and make a good and reliable solar light set. I had the idea, just not the specifics.

    1 reply

    I promised my Dad I would make this for him last summer. I even had all the parts sitting in my basement for the past year. I'm glad I waited because I learned quite a bit during that time which helped me with this project. I could have done it, but not as nicely.

    If you go with some cheap 1W LEDs and a low cost driver and charge controller, the project's price tag is between $50-100. The biggest issues are the cost of the solar panel and the battery. I got my battery on sale for $10, it's normally $20ish. Same with the solar panel, a random online sale last year.

    It's not an overly difficult project, but it does take some time to find and order all the parts. I made a third "head" the other evening and it took all of 10 minutes to do and wire into my setup.