Solar Garden Lights on a Larger Solar System

I was looking for a 12v garden lighting system for my backyard.

While looking around online for systems nothing really grabbed me and I didn't know which way I wanted to go.
If i should use a transformer into my mains power or go solar system.

I already had a solar panel that I purchased some time ago, for a project that I never got around to doing, so that was enough to push me into making my own 12v garden light system, using up my solar panel.

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Step 1: Equipment & Tools Needed.

Equipment Needed.

  • 1 x 80w Solar panel (already had laying around)
  • 1 x 12v 18ah Battery (ebay)
  • 1 x 40A Solar Panel Regulator Battery Charger Controller 12/24V (ebay)
  • 1 x 20m Garden Lighting Cable (Bunnings / hardware store)
  • 1 x AC DC 12V 10A Auto On Off Photocell Street Light Photoswitch Sensor Switch (ebay)
  • 10 x LED Strip light connectors to suit 5050 LEDs (ebay)
  • 20 x Scotchlok Wire Connector 316 IR 0.5mm - 1.5mm (ebay)
  • 1 x part of 5M 300led 5050 LED SMD Flexible Strip Light 12V Waterproof (re-used from umbrella project)
  • 10 x Lectro Mini Solar LED Bollard (Bunnings / hardware store)

Tools Needed.

  • Electric Drill
  • Scissors
  • Wire cutters
  • Pliers
  • Super glue
  • Tape

Step 2: Attaching LEDs to Reflector Section of the Light

I was going to play around making my own bollard but after messing up a couple of prototypes and really wanting to get the job past the drawing board, I went with a cheap solar light that I could retrofit.

I choose this light fitting for a couple of reasons.

  1. It was cheap, at $2 a light.
  2. It came apart in sections, so i could manipulate it, without to much effort.

Once I pulled the bollard apart, I had 4 sections:

  1. The top solar and bulb section, which I left turned on even though it didn't give out much light at all
  2. The clear cylinder that had a silver reflector at the bottom
  3. The empty silver tube
  4. The plastic garden spike.

I drilled a small hole in the clear plastic cylinder, through the reflector at the bottom, there were four little air holes in the clear plastic cylinder already, so I just made one a little larger to fit the connector wires though.

I then joined up the connector clip to the LED strips, I made sure there were 6 LEDs per strip and then pushed the connector clip down into the clear cylinder. (The reason I used 6 LEDs per strip is in step 4 )

I bent the LED strip over, so 3 LEDs of the strip where push against the cylinder wall, and pointing out the front and the other 3 where pointing down from the top to the bottom reflector. I did use a little super glue to hold the LEDs in place. This was to keep the LED from bending all the way over when pushing the top back on the clear cylinder.

Step 3: Attaching Wires to Bollard

Now that the light component was built, I needed to re-assemble the bollards and wire them to each other.

First I needed to drilled two holes into the bottom garden spike, this is where I will be threading the Low Voltage garden cable, so i can connect the lights in a parallel wiring configuration.

One hole for incoming power (positive and negative wires) and the other hole for the outgoing power to the next bollard (positive and negative wires).
The holes were just big enough to push the wires up all the way up into the silver tube, so they could be connected with the clear cylinder.

On the black wire I purchased, it came with two black wires joined together, the only difference between the wires, was one wire had writing on it and the other didn't.
I used writing on the one wire to identify it as the positive wire, so even though i was dealing with two black wires, I could tell what was positive and negative by looking for the writing. I cut the wire at about 1.5m between each bollard.


Now at the top of the silver tube, you should have 6 wires you need to join for each bollard - the 2 incoming wires from the battery source, the 2 wires from the LED light component and 2 wires for the outgoing wires to the next bollard.


So all we need to do is, connect one of each of the negative wires, 3 in total together.Then the same with the 3 positive wires.
To do this I used the Scotchlok low-voltage irrigation connector. I liked the fact they had gel in the connector to keep the connection free from moisture plus the quick crimp function. Once i had the processes in place, adding one bollard to the next, didn't take much time at all.

The last bollard only had 4 wires to connect, which was the 2 incoming wire from the previous bollard and the 2 from the light component for the LEDs, so we only needed to join the 2 negative wires together and then the 2 positive wires together to finish off.

I tested the lights with the battery before I took them out to the backyard, making sure everything worked. It did!

Step 4: Solar Panel, Battery, Controller and Photocell Switch.

Now the bollards are completed, I needed to set up the solar system.

As I mentioned before I had a 80 watt solar panel, so I worked around that.
To replace 18A/h of charge to the battery each day, and if I work off 8 hours of sunlight in each day, I will need :
18AH x 12V = 216WH. 216WH / 8H = 27W solar panel. Seeing that my panel is a 80 Watt panel it will be more than enough to charge my system, even if i double the batteries for more lights later down the track.

The bollards are made up of 6 x 5050 SMD Bright LEDs - and we have 10 bollards which = 12 watts in total

  • The LED strip I partly used, was part of a 5 metre (5000mm) strip made up of 300 LEDs in total.
    (60 LEDs per/m) and around 12W per metre (60W in 5 metre total)
    I used 6 LEDs per light so around 100 mm per strip, and 1.2 watt per bollard.
    10 Bollards = 12 watts needed
  • Added info: 300 LEDs divided into 5000mm is one LED per 16.66mm - which I was using to work out how many Lumens I wanted per length. One LED on the 5050 LED gave me 16-22 lumens. - so in the end, 6 LEDs on the 5050 strip gave me 96-132 lumens which is about 15 watt incandescent bulb.
    3 LEDs wouldn't have been bright enough, and 9 would have been to long a strip for what I wanted.

The Battery ordered was a 12v 18ah

  • So once I worked out how many watts I needed to power the lights, and how many hours i wanted the lights to run, I ordered the battery, which was 12 volt and 18ah which covers me for the 10 - 12 hours of night light.
    I used a couple of online calculators to make sure i got it right, like the one at R & J Batteries they have a deep cycle battery calculator. I did add a little wriggle room with the ah's so I could add a light later if needed.

The Battery Solar Controller 40ah

  • The battery solar controller I ordered was for 40ah, in case I wanted to add more lights down the track, I could add another battery and the controller would be able to handle the two 12v 18ah batteries which is 36ah in total and under the 40ah of the controller.
    I also choose this one, because i could see what the output and input was on the display.

The Auto On Off Photocell Sensor Switch

  • I also wanted the lights to be able to turn themselves on and off, with the day or night time sensor in the Photocell, I was able to achieve this. I did try a cheaper one from ebay, which didn't work, but this one worked great, just had to make sure I placed the unit in the right place, so the morning sun would turn off the lights, and turn it back on at the last rays of light in the evenings.

Step 5: Wiring Up the System

The controller made wiring up the system simple.


The positive and negative wires from the solar panel where brought down into the shed where I had the set up, the controller had a little solar panel icon, with positive and negative signs, it made it easy to attach the wires in the correct order.

The same with the battery, the positive and negative signs with a battery symbols on the controller, made the wiring a breeze.

The last section was the load, this is where the lights are attached, the controller has a little light bulb picture with positive and negative signs. But I needed to add the photocell switch between the controller and the lights. So even if the controller sends the power from the battery to the lights, the photocell has the final control and will only let the power pass when the photocell is in the dark.


I made a little wiring diagram image to follow.
To wire the photocell, the outgoing power from the controller (shown in the diagram as red) goes to the black photocell wire.
Then the outgoing power from the photocell to the lights comes from the red photocell wire to the light load.(shown in the diagram as purple)

Then the negative wires from the controller and the negative wires from the lights all join up with the photocells white wire. (shown in the diagram as black)
I then positioned the photocell where the day time light hits it so the power doesnt run out of the battery through the daylight hours.

I finally pushed the button so the controller, I could see it was sending power to the load by the display screen, and tested the photocell with my hands covering the photocell unit so, no light would hit it, I could hear it tick over and light up the bollards. It worked perfectly, I removed my hands and as the light hit the photocell the unit ticked again and the lights turned off.

Step 6: The Outcome.

In the end, I am really pleased with how it turned out. I can see around my dark backyard, the edges of the garden path, which I couldn't see before. It also brings light to the garden which makes it special in its own way, which was what I was hoping for.

There will be more lights added in time. Plus i might try again with building my own bollards next time. But for now I will sit back and enjoy the lights over the Spring and Summer months that we are now just heading into.

I hope you enjoyed my instructable.

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    2 Discussions

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    ALadyDragon

    15 days ago

    Hi Fred
    Glad you enjoyed the instructable. Thanks for the link.
    I didn't need to source any bulbs for this project, because I was re-using the LEDs I already used for my umbrella lighting instructable.( https://www.instructables.com/id/LED-outdoor-umbrella-lighting/ ) I don't use the umbrellas any more due to having a patio built recently, so I wanted to re-use what I had like the solar panel and LEds.

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    FredTSL

    19 days ago

    Hello,
    I've done the same thing in my garden for quite a while now. The main difference is that for simplicity, I found 12V "bulbs" on chinese site (eg :https://fr.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190903234320&isPremium=y&SearchText=12v+Gu10&switch_new_app=y) and I just discovered that almost of type of lamp can now be bought in 12V, so you can add ligths from any vendor with not much change to it.
    Also, one thing to think about. Given the small voltage, use the appropriate cable for the power you want to have. Not really important in your case with less than 50W, but If I light everything; I can now have almost 300W if I combine all automatic and manual lights and it's almost 30 A (my battery is a 100Ah, and the solar pannel is a 200 and actually, I never have everything light at same time).