Because I always wear long sleeve shirts at the direction of my dermatologist, my solar watches rarely have the opportunity to get a quality charge. Being disappointed by the quality and/or price of solar watch chargers, I decided to have a go at making my own. After SEVERAL prototypes and redesigns, I decided to go with battery power instead of a USB or wall charger. The end result is the SOL-TIME solar watch charger**. Powered by a single AA or CR123 cell, a Nichia HS LED is focused onto the watch dial and rapidly charges the cell (and lume) at 22mA. Here the SOL-TIME is charging my Citizen Promaster Eco-Drive. This watch really lives up to the nickname of "Lume King". Since the pictures were taken, I have added a 3D printed cover to protect the circuit and provide and strain relief for the negative lead.
Charging my watch in ambient light.
An overhead shot showing the intensity of the light on the solar cell.
In the dark. As a bonus (or negative) the light from the charger is sufficient to easily navigate in the dark room.
If I wanted to charge the watch over night, I would need to 3D print a cover or shield to contain the light.
I had considered 3D printing a housing that would have the LED face upward, so I could place the watch face over the light. However, I chose to go with this simple design as I only have two solar watches at this point. If I end up getting a Seiko Solar Tuna or Citizen Orca, I may revisit this project and cook up something more elegant. For now, this works for me and has been doing a terrific job of charging the watch.
**I decided to get creative with the PCB artwork this time, as I was really impressed with the detail that the fabricators were capable of.
Charging my watch in ambient light.
An overhead shot showing the intensity of the light on the solar cell.
In the dark. As a bonus (or negative) the light from the charger is sufficient to easily navigate in the dark room.
If I wanted to charge the watch over night, I would need to 3D print a cover or shield to contain the light.
I had considered 3D printing a housing that would have the LED face upward, so I could place the watch face over the light. However, I chose to go with this simple design as I only have two solar watches at this point. If I end up getting a Seiko Solar Tuna or Citizen Orca, I may revisit this project and cook up something more elegant. For now, this works for me and has been doing a terrific job of charging the watch.
**I decided to get creative with the PCB artwork this time, as I was really impressed with the detail that the fabricators were capable of.