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Adding a larger capacity solar charger to existing LED post lights


LED Post Cap 


Modification Stages

2"x2" Wrought Iron Post  LED Post Light Fitted  Solar Control Added Rain Cap Added 


Both  Dusk to Dawn Solar LED Light and 2"x2" LED Post Cap are modified before fitting.

The 2"x2" LED Post Cap has a 220Ω resistor added in place of the existing resistor to allow for the increased voltage of the Dusk to Dawn Solar LED Light.

The Dusk to Dawn Solar LED Light has the LEDs in the case disconnected and a cable is run from the LED output up the inside of the 2"x2" post to the 2"x2" LED Post Cap LED.


                          Dusk to Dawn Solar LED Light 2"x2" Wrought iron post           2"x2" LED Post Cap




2"x2" LED Post Cap

The LED caps are designed to fit into a 2"x2" wrought iron fence posts.

They are completely self contained with a single LED powered from a 600mA NiCad battery.



To keep the design nice and compact the battery is charged from a 40mmx40mm solar panel built onto the top of the post cap.

The image below shows the modified PCB with wiring removed and the new 220Ω resistor in place.

The lights work well in summer when the days are long but once winter comes when they are needed most they only last a few hours.

With the solar panel mounted on top of the light they are very inefficient at gathering sunlight especially in winter when the sun is low.


The top mounted solar panel also causes problems with water ingress.

When it rains water sits on top of the solar panel and eventually works it's way through and drips onto the circuit board.

A small clear plastic guard sits over the PCB but this is not enough to stop the PCB from getting wet and corroding causing the light to fail after a couple of years.

As well as silicon sealing the solar panel to the cap a 3D printed rain cap is added over the top of the cap.


The original LED cap charge and light section is shown below.

The single rechargeable AAA battery has been removed to show the PCB and LED resistor.


Remove all the wiring including the wires to the solar panel.

Cut out the original resistor. 

Solder in a 220Ω resistor and connect the +ve & -ve to the dawn to dusk control LED output solder pads.

Original Post cap

3D Printed Post Cap Rain cover





The 3D printed cap is hollow so it can be placed over the top of the original cap.


The 3D printed cap is glued in place



The 3D printed cap in place keeping rainwater out


 Dusk to Dawn Solar LED Light

The LEDs are disconnected on this unit and a 2 wire cable is taken up the inside of the fence post and connected to the LED in the LED Post Cap.

Side profile

The case is held together by 4 screws in the back of the light

After removing the 4 screws the case can be prised apart

The wires to the LED Panel are then disconnected

Wires are then soldered to the LED +ve and LED Gnd on the PCB and cabled up the inside f the post to the LED of the LED Cap Light

Front Panel Rear

The 2 wires to the LED Post Cap are routed out of the case via the 2 slots below the LED panel.

Rear panel with all wiring removed showing PCP and 600mA Battery locations. 




Dusk to Dawn PCB Connection Detail



Wrought Iron Posts & LED Post Caps round the edge of a drive


LED Post Lights in use around a raised hard stand