Here’s how to make solar-powered outdoor lights connected to a post in your backyard.
A few years back, we installed a sun shade sail in our backyard. We love having the shade (check out the sun shade sail DIY), but we always wanted to turn the wooden posts into something more.
I am fascinated with solar power. I love the environmental benefits and the direction to move off the electrical grid. It’s a great feeling knowing you can generate electricity from something natural.
So I figured the shade sail posts could serve a dual purpose – anchoring the sun shade sail and providing solar power lighting.
It was perfect timing for our monthly DIY challenges. We are collaborating with a lot of talented DIYers to share themed projects, and this month’s theme is to fix up something outdoors. Last month, the theme was home improvement and we redid our pantry with new shelves and drawers and wallpaper.
There are usually four parts to most solar-powered outdoor lights – solar panel, battery, charge controller and load (such as a light bulb).
A solar panel produces electricity from the sun and charges up a battery.
The battery is used to power electrical things like light bulbs.
A charge controller is needed so that the solar panels do not over-charge the battery and damage it.
Solar panels come in many different wattages, depending on how much power you want to generate.
To decide on a wattage that was appropriate for me, I had to think about what I wanted to accomplish. I really just wanted some lights in the backyard that turned on automatically at night and remained on for a certain amount of hours.
There are many solar lights you can purchase from the store that do something similar.
However, they are usually motion activated, not very bright, and don’t usually stay on for hours.
To build my setup, I needed to power my light bulbs with a decent sized battery.
I opted for a 20ah deep cycle battery, which I calculated would provide enough electricity to power several bright 12 volt light bulbs all night long.
These batteries are similar to your average automotive battery, except about 1/3 the size, and designed specifically for powering devices over a long period of time.
Now that I’ve decided on a battery size, I needed to come up with a wattage for my solar panels.
I needed a solar panel powerful enough to fully charge the battery during the day so that the lights would be operational at night time. Finally, I settled on a 100-watt solar panel.
For the solar panel charge controller, I didn’t need anything fancy. I just choose a cheap one with good online reviews. It was important that it had a timer though, so the lights could turn on and off automatically.
LED light bulbs are a requirement for almost any solar-powered project.
Incandescent light bulbs (and many other types) suck up way too much electricity to be powered practically by a battery. I searched around for 12-volt LED light bulbs and settled on some fairly bright ones (7-watt ones, equivalent to a 60-watt incandescent bulb).
12-volt bulbs were needed as the battery was a 12-volt battery.
Most LED light bulbs used around the home are 120-volt bulbs, and would not be compatible with my solar-powered project.
Also, I needed an exterior lamp fixture to install the light bulbs into. I found some nice 12-inch globe fixtures online that would be perfect to mount on top of my shade sail posts.
100-watt solar panels are fairly large and heavy (around 30″x40″ and 20 lbs). So I needed to come up with a sturdy design to mount the panels on the posts.
Here is the design I came up with for the solar-powered outdoor lights:
The solar panel would be attached to an adjustable mount.
It’s adjustable because it can change the angle of the solar panel to maximize electrical generation.
Depending on your geographical location, adjusting the tilt of the solar panel in the summer and winter can help ensure you get the most out of the sun’s power.
The adjustable mount would then be attached to a fixed post mount.
On the opposite side of the post would be a small weatherproof enclosure to store the battery and charge controller.
The globe lamp fixture was affixed to the top of the post.
With the design fleshed out, it was time to start constructing the parts.
The weatherproof enclosure for the battery and charge controller consisted of two separate compartments. The upper compartment stored the battery, while the lower compartment housed the charge controller.
First, I needed to construct the box for the weatherproof enclosure.
Here are the cutout sides of the box:
I joined the sides of the box together with construction adhesive and finishing nails.
A bar clamp came in handy to hold the pieces in place while I used my finishing nail gun:
Here I inserted the battery and charge controller to get a rough idea of how things would look:
The charge controller would later get a more elaborate design to allow it to be easily removable for installing various wires.
Deep cycle batteries can get a little warm when charging, so I drilled some ventilation holes in the side of the enclosure. I made sure to drill the holes at a 45-degree angle to prevent rainwater from dripping in.
There was also a hole at the bottom of the battery section to run a wire to the controller.
Here I covered the interior of the holes with insect screen to prevent my enclosure from housing unwanted visitors:
Next, I stained the enclosure with weatherproofing stain (the same one I used to protect the shade sail post). I also caulked the inside corners for extra protection against water seeping in from the outside.
Here I’m getting ready to attach a 1/4″ plywood roof:
I had some roofing material left over from a prior shed project, so I was all to happy to be able to use them again.
To waterproof the roof, I first laid down a layer of roofing felt, aka tar paper (I used some staples to hold the paper to the wood):
Next, I cut two strips of shingles and nailed them down to the enclosure:
The upper shingle strip covered the nail heads for the strip below.
However, with no other shingles to overlap the upper shingle, there were exposed nail heads on that shingle.
So I used some roofing cement to cover those nail heads and blend them into the shingle.
With the enclosure roof done, I used my table saw to cut out covers for the battery and charge controller compartment.
The battery cover was just a piece of 1/4″ plywood. Whereas, the charge controller cover was made from a strip of 1/8″ plexiglass.
I wanted the charge controller to remain visible so I could monitor the system status without having to remove anything.
The controller came with a handy digital display with various bits of information (like if the solar panels were charging, or what the remaining charge on the battery was).
Here is the mostly completed enclosure (I still had to stain the battery compartment cover):
The next part of the solar-powered outdoor lights project was to work with the charge controller.
To make it easier to attach all the wiring to the charge controller, I came up with a module design that allowed the controller to be easily removed.
The charge controller was attached to a rectangular piece of wood (with some handy 1/2″ screws), which was secured to the enclosure via two short deck screws.
Instead of attaching the wires from the battery, solar panel, and lights directly to the controller, I opted to use a terminal block as a middle man. It was attached to the opposite side of the controller module.
Here’s the front of the controller module showing the charge controller wired up and ready for action (notice the addition of a toggle switch to manually turn off the lights):
And here’s the back of the module showing the terminal block, awaiting connections from the peripherals (lights, battery and solar panel):
With the enclosure complete, I moved on to the solar panel mount.
It was a relatively simple design in the shape of an “I.”
I used 2×6 boards for maximum strength.
Here are the mount parts placed roughly in place on top of the solar panel:
I joined all the pieces with long deck screws. Also, I reinforced some of the joints with L brackets and structural screws:
Here is what the solar panel looks like when attached to the mount:
Next, I built the post mount. It was in the shape of an “H”, and also made of 2×6 boards:
At his stage, the post mount was a pretty simple design. I later decided to add 45-degree supports made from 2x4s to further strengthen the entire mount.
The solar panel mount would sit in between the segments of the post mount, connected with 4 heavy-duty bolts.
Two of the bolts would allow the solar panel mount to freely rotate to the desired angle. The remaining bolts would lock in the chosen angle.
During construction, I had pre-drilled bolt holes in the mounts to allow for a 45-degree tilt of the solar panel. When the mounts were securely attached to the shade sail post, I planned on drilling another pair of holes to accommodate a 30-degree tilt.
Here are the two mounts connected to each other (only one pair of bolts was inserted, so the solar panel mount could rotate freely in the post mount):
To protect the wood from the elements, I applied at least 2 coats of weatherproofing stain to all exposed surfaces.
Here’s a picture of the post mount (with some 45 degree 2×4 supports added) showing some of the staining in action:
To secure the 2×4 diagonal supports to the 2×6 boards, I drilled some pocket holes and reinforced the connection with 2 metal ties.
Below, I made the mounts for the lamp fixtures.
These lamp fixture mounts weren’t in my original design.
The lamp fixtures were originally intended for a 3″ diameter round post, not a 6×6 square post. So I was having a lot of difficulties accessing some of the screws for the lamp fixture when attaching them to the posts.
I decided to raise the lamp fixtures about 1.5″ above the top of the posts for more clearance.
Next, I made the mounts with some 2×4 cuts. Then I drilled a hole in the center with a hole bit, and counter-sunk some screw holes for attaching to the posts.
So far, I was pretty pleased with the solar-powered outdoor light project. Everything was built at this point and finally ready to be assembled outside.
First, I installed the post mount (secured to the lamp post with 12 galvanized lag bolts):
Then the solar panel mount followed (attached to the post mount with 4 heavy-duty bolts):
I was really excited to secure the solar panel to the mount next, tilted to 30 degrees. So, I used some structural screws to fasten the solar panel to the mount.
The battery and charge controller enclosure went on next (mounted to the lamp post with 2 galvanized lag bolts and large washers):
Then, I installed the first lamp fixture on top of the post:
Next, I dug a shallow trench towards the other lamp post to run some landscaping wire to:
I buried the landscaping wire and compacted the ground with a tamper. There was now no trace of a wire running between the two posts.
Next, I wired up the second lamp fixture on the remaining shade sail post:
Finally, I hooked up the lamps to the solar panel charge controller and was able to successfully test the lights. Here’s a close-up of the charge controller in action:
The solar-powered outdoor lights were finally complete!
It was a really fun project to work on. I was able to build everything within 3 days and a budget of around $250. It was expensive, but using the parts I have, I can hook up other backyard items to the solar power too.
I tested the system during the night and it worked flawlessly.
When the sun went down, the lights came on and remained on all night.
By morning, the remaining battery charge was around 70%. And by afternoon time, the battery was back up to full charge from the solar panels, ready for another night of work.
Here is the completed project:
I will describe how to make a solar LED garden light from scratch, using the 5252f part which runs the light at night once the light on the solar LED gets low. It also keeps the battery from draining down too much and damaging the battery. It does not have an overcharge circuit. Be careful not to put too much of a solar panel, in milliamps, as you can overcharge the battery. But you might consider larger solar panels for AA batteries (rather than a AAA battery), or in places where the device might be indoors and not get a lot of sun, or only in direct sun for a limited time per day.
Check out my YouTube video covering this article. While this article goes into more detail in some spots, it does not contain all the information in the video, so check out both.
Finished solar LED lights. These are the color changing LED type.It’s up to you how to mount the electronics. Will it be to replace an existing solar LED device, where the electronics were damaged, or you can’t get to work? You can replace the circuit board with one you make, and still use the existing solar panel in the device. While I have repaired many of these solar devices, in some I’ve had to replace the electronics completely. Or you can make your own container out of a jar, a candle holder, or like in my case, shot glasses.
If you make your own, you could use a piece of plexiglass to make a cover for a jar or candle holder glass container. The solar panel could be glued on top of that with silicone, and then drill a small hole for wires, and the circuit board and battery could be placed under the plexiglass lid with silicone. You want to make sure your container is fully sealed against water, as water is one of the enemies of solar LED lights.
My workbench is all setup to make some solar lights. The black round caps are the solar panels, and the cap allows me to tuck the circuit board and battery up inside it.A basic solar LED will need a small circuit board piece, one 5252 part, and a 220uH inductor. You will need a rechargeable 1.5 volt battery, and a 2 volt solar panel. I used 26 gauge silicone coated wire to hook everything up, and soldered the battery directly. A switch is another place to go bad, water gets in on/off switches and ruins them, and your solar LED quits working. The 5252f part will output 3mA to 300mA, and up to 1.5 volts.
For this article, I made some color shifting LED solar lights. A color shifting LED can be purchased, and then all you need to add to the 5252 part and inductor is a capacitor and a diode. The capacitor is a .1uF or 104 capacitor (I used a 50 volt). The diode is a BAT85 200ma, 30 volt diode. I think a clear glass container works best for this project, since the LED changes colors. The color shifting LED I used is called a 5mm RGB slow flashing LED.
The main part of the solar LED, the 5252f, you can get a bag of 50 of these for fairly cheap.You will need to solder to make this project. I also have links below to a soldering iron, to help you get started if you haven’t done that before. I bought the parts in bulk. The 5252f, inductor, capacitor, diode and LED’s can easily be bought in bulk, so if you make multiples of these, those parts end up being very cheap per each solar light. You can always make a lot of these to give away to friends, family, neighbors, etc. What I found the most expensive was the glass I was putting the LED in, followed by the battery.
A 220uH inductor works well for a standard LED of about 20ma. Or you could use higher values, for example a 330uH to get a slightly lower brightness, but have the LED last longer through the night. For a very bright LED such as a .5w that takes 100ma or so, you would probably use a 33uH or 47uH inductor, again, the higher value, the less current, and longer it will last through the night.
Here’s a chart of various inductor values, so you can get an idea how many millaamps each one will output. If you are getting a brighter LED for example (that takes more power), you’d want a lower value inductor.
330uH puts out 11mA
270uH puts out 14.5mA
220uH puts out 15.5mA
150uH puts out 25mA
100uH puts out 34.5mA
82uH puts out 38mA
56uH puts out 50mA
47uH puts out 75mA
33uH puts out 110mA
The above values can be calculated for other inductor values (if I figured this out correctly), by taking 3750 divided by inductor value. This will give you the milliamps that the circuit will output. For example, 3750 divided by 100 = 37.5 (close to the 34.5mA in the above chart numbers I found online).
To figure out the inductor value for a given milliamps desired take 3750 and divide by the mA wanted. For example 35mA/3750 = 107uH, or round and get a 100uH inductor.
The cheapest way to buy the parts is probably in bulk. If you just want to make 1 of these, I don’t know where you’d find one of each part, but the price would be a lot more. So consider that you can always make several of these, and probably still have leftover parts.
A circuit of a solar LED light without the color changing LED, but just a single color LED. A breadboard has all the columns in the middle section connected. Each hole below the 5252f part is connected. The top row is all ground.You can get either AA or AAA rechargeable batteries. AA batteries will take more of a charge, thus could be used with a larger solar panel, maybe 100ma. I used a AAA battery to fit in the solar cap I bought, also purchased in bulk.
The completed circuit. The red wire goes to the positive of the battery, the white wire is the positive solar lead. The yellow wire is the positive LED wire. The black wires are all grounds.Start with making a circuit board. I bought some little pieces and cut them down so each small piece had a 4 x 6 hole pattern in it. This size works great for a color shifting LED project. You can make it smaller I’m sure for a solid single color LED, as you won’t need the diode and capacitor. I’d say for a one color LED project, a 3 x 5 pattern of holes would be large enough. When cutting the PCB board, cut down the middle of a row of holes.
The front and back side of the circuit boards.Layout the parts according to this image of the back of the circuit board. What you are looking at is not the parts side, but the side with the leads, where you will be soldering the parts together.
Connections on the back side of the circuit board. Components are on the other side.Connecting the circuit takes bending the leads over so they reach the next pad. For example: pin4 can be bent to the left to hit the inductor, the inductor lead can be bent to the upper left to hit the diode. Then solder at the inductor to pin4, and at the diode positive side. Clip off the excess leads.
At the bottom near the middle, bend the capacitor lead upwards and over to pin 3, the ground. Bend pin3 up and near the hole for the ground wire. Solder pin 3, and trim off any excess from the capacitor (if any). Leave the pin3 bent upwards towards where the ground wire will connect for later.
Bend the inductor upwards to pin2. Bend pin2 upwards next to the hole where the wire will be connected to the positive side of the battery. Trim any excess off from the lead from the inductor, leaving pin2 still going up towards the positive battery hole, which we’ll do later.
Pin 1 of the 5252F is bent up towards where we will solder the wire for the solar panel positive lead. When you solder that lead, make sure you also solder the wire from pin1, which should be bent so it is right there touching the wire going to the solar. The wire itself will be on the other side of the board, just the end of the wire will be barely poking through this back side of the board.
I used 26 gauge silicone covered wire. I like this wire, as if you accidentally hit the insulation with the solder iron, it will not burn off. It is very flexible wire also. I got a set of the wire, which had five different colors of wire, with about 33 feet (10 m) of wire for each color. This is great for many projects.
You will need four wires connected next. The wire itself is on the component side, so I can solder the wire on the back of the board. The length of wires will depend on how you are connecting your project together, and how far your LED and solar panel and battery will be. Mine were pretty close together, so my wires are all about 1.5 inches long (40mm).
I used a yellow wire for the positive going to the LED. Cut that and strip off the insulation on both ends. You won’t need to strip off much insulation, enough to go through the circuit board and stick out a little, and just enough to be soldered along the positive LED lead. On the bottom left side, make sure at least one of the capacitor or diode- leads is bent over and going near the corner hole you will use for the LED wire. Stick the wire through the board and solder it on, making sure the capacitor/diode wires (both come through the same hole in this case) are soldered with the yellow wire. Make sure the hole with the two wires coming through is also soldered, and cut off excess leads.
I used a black wire for the ground wire. Since other wires will be connecting to this, I used one wire coming off the board, and connected the other three wires to this wire. I cut more insulation off the end of this wire, to allow for easily connecting the other three wires. Bend pin 3 up alongside the ground hole. Put the wire with the end with only a little insulation removed through the ground hole, next to pin 3. Solder the wire in place, making sure to solder the pin 3 wire resting on it also.
I used a red wire to go to the positive side of the battery. Remove some insulation off both ends. Bend pin 2 up right alongside the hole for the battery plus wire. Push the wire through the battery plus hole from the component side, next to pin 2. Solder the wire in place, making sure to solder pin2 also.
The last wire to the board is for the positive solar. My solar cap already had a wire, so I just used it. Bend pin1 up alongside the solar positive hole. Put the solar wire in from the component side, and solder it in, making sure to solder it to pin1 at the same time.
Cut two black wires to attach to the black ground wire on the circuit board. One will go to the battery negative, one will go to the LED negative. My solar cap already had a negative wire. If you are using a basic solar panel, but a third wire for the negative of the solar panel. One each of the cut wires, strip the insulation off one end a bit more than usual, to make it easier to connect them all together for a ground wire. Twist the four ground wires together and solder them.
I slightly sand the battery ends to clean them up so solder sticks well. Attach a bit of solder to both ends of the battery. Try to make this as fast as possible, as batteries can be damaged by extreme heat. You can always put a metal wrench or screwdriver end onto the end of the battery when you are done, to try to bleed some of the heat into the metal tool, and out of the battery.
Solder the red wire to the positive side of the battery, and one of the black wires to the negative side of the battery. Solder the positive side of solar panel to the wire from pin1 if you aren’t using a solar cap (if you are using a solar cap, the wire was already there, and you should have soldered it on already).
Now put some heat shrink tubing around the wires of the LED. Alternatively, you can use some tape, or even silicone to put around the leads so they don’t short out. If you use heat shrink tubing, put some on the LED leads, but leave some lead sticking out. Put a couple short pieces of heat shrink tubing on the two wires you are going to solder to the LED. Solder the LED, the longer lead is the positive lead so hook the yellow wire to that. Solder the remaining black wire to the shorter LED lead. When you do this, your LED should light up if your battery has a charge.
Another way to tell the LED leads apart, the negative lead usually has a flattened edge on the round LED.
The solar caps. I dripped epoxy around the edges of the glass panel, so water cannot get under it.I used a toothpick to drip epoxy around the edges of the glass covering the solar panel on my solar caps. The idea was to keep the water out from under the solar panel. Water is a major issue with these solar LED’s, so you want to try your best to make sure water can’t get inside these. Maybe this was an overkill, but I feel better knowing water can’t get under my solar panel. Just a word of advice about epoxy: I had a lot of trouble using the Loctite epoxy I’d get at the local box store. This stuff was of terrible quality and comes loose. I bought a couple of larger bottles of epoxy (yes, epoxy is expensive!), but maybe you can try something like the Gorilla brand (I haven’t tried that yet, let me know how it is in the comments). One more hint: if your resin ever crystallizes, don’t toss it out! It is like honey. Stick it in the sun, and it will turn liquid again.
I put the battery inside the plastic cap at an angle, with the circuit board. Make sure the circuit board it set so that it doesn’t short out against the battery. I then used silicone to glue the parts in place. I used my little holder to hold the LED upright (since the entire assembly is upside down), so it will hang down inside my glass. Then I dabbed silicone on the battery and LED wires, once the silicone dries, that holds the LED in place so it will hang in the center of the glass.
I then used my finger to place three dabs of clear silicone around the edges of the shot glass. Since the shot glass and the solar caps had about the perfect diameter to be glued together, I could glue them together directly. The three dabs of silicone, once dry, hold the cap in place, so I could put a line of white silicone around the edge. The white silicone not only holds the solar cap on, but it keeps water out of the inside of the glass. After putting a thin line of white silicone around the edge, I double check to make sure there are no holes in the silicone, if so, I smooth those slight with my finger. Making sure there are no holes, makes sure no water gets in a hole. Then I spray a soapy water mix on the lid, and my finger, and make one pass around the edge of the glass, which smooths the silicone almost perfectly.
If your project doesn’t fit perfectly together, one idea I had was to cut Plexiglas pieces to fit the top of the jar or glass container. Then I can either mount the solar cap, or just a regular solar panel to the Plexiglas. If just a regular solar panel, the circuit board and battery can be mounted under the Plexiglas, inside the container. You’ll need to drill a small hole in the Plexiglas for the wires. Make sure the everything is well sealed. Water damage is the leading cause of issues with garden LED lights.
I used Godinger Dublin shot glasses, a cut crystal look, which throws the LED light around in interesting patterns. The solar caps fit the top of the shot glass very well, and just need to be siliconed on. I did have to remove a couple of the solar caps on glasses that friends had dropped (without breaking the glass!). That knocked out the circuit board from the cap, which I hadn’t attached well enough to the cap. My newer versions I tried to make sure are attached much better.
I put blue tape over the solar panels, then painted the caps white. My thought is the battery will last longer if it is cooler inside the cap. With a black cap, it seemed like that would heat up quite a bit.With a AAA battery, during the summer, these lights are still going in the morning when the sun comes up. I’m not sure how long they’d last in the winter with the shorter days and longer nights.
Several of the color changing LED lights in the birdbath at night.I think these LED lights will last quite a while. Water can’t get in them. There’s no switch to get wet and go bad. The wires are nice quality, and won’t easily break off. Until the battery goes bad, these should work nicely for years. Which is quite the opposite of the ones you buy.
I’d love to hear how your project went in the comments. Also please comment if I have a mistake, or you found a better way to do something. Thanks!
Tools:
budget soldering iron: https://amzn.to/2Sn89BT
Better soldering station: https://amzn.to/2G9Jviu
budget multimeter: https://amzn.to/2DRAjwU
Better multimeter: https://amzn.to/2G7CXRx
battery tester: https://amzn.to/2MOxkba
wire stripper: https://amzn.to/2t73HJa
I didn’t need a multimeter for these new solar LED’s. I lucked out, and each one I made worked the first time. It is possible you may need one to help locate issues.
Parts:
Silicone sealant (clear): https://amzn.to/2DTrmmR
Silicone 10.1oz tube, white: https://amzn.to/2DVakqy
Circuit board pieces (could make 36 circuit boards): https://amzn.to/2FdrDUH
Heat shrink tubing to insulate wires: https://amzn.to/2XSmgR5
Shot glass (set of six): https://amzn.to/30I9eaQ
QX5252F Solar LED IC driver: https://amzn.to/2Gtzyvt
LED Kit (replace or change colors): https://amzn.to/2GlWa19
LEDs, white: https://amzn.to/2t3wZs4
RGB Slow Flashing 5mm LED: https://amzn.to/3iwUiCp
Silicone covered wire: https://amzn.to/2MMmZfR
AAA NIMH battery: https://amzn.to/2GlKaN6
AA NIMH battery: https://amzn.to/2MTX6uL
0.1uF capacitor for color change option: https://amzn.to/3iqPnTx
BAT85 200ma 30 volt diode for color change option: https://amzn.to/31FGxdY
Inductors 220uH 1W: https://ebay.us/tn7Bir
Solar Panels:
Solar caps (quantity 10, other quantities available from seller): https://ebay.us/YrdRD3
60mA 2 volt round (qty 5): https://amzn.to/33HkA0G
60mA 2 volt square (qty 5): https://amzn.to/3ixlTU9
160mA 2 volt square, low light locations (qty 5): https://amzn.to/3ixmiWF