5€ Solar Watch Charger

Needed a way to keep my Casio G-Shock Square charged during winter

Markus Napp

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Description

I own a G-Shock Square that I wear everyday and have done so for 5 years. Last year I had another child and didn't make it outdoors as much as I used to.

I had looked at commercial solar watch chargers before (looking at you Coolfire) but I never actually saw how that investment would make sense if I only ever used it on one watch and only for a couple of days out of several years.

Then I was browsing the IKEA website for new USB and LED stuff and noticed the KAPPLAKE spot that was small enough but delivered enough power. According to my phone my little setup dumps 20000+ Lux of energy onto the solar cells of the watch. I put the contraption on my watch when I'm working my basement home office so it gets about 6 hrs of solid light and charged my watch up from 1/5 to full within 3-4 sessions.

The materials are a 4€ LED KAPPLAKE from IKEA, 30ct€ herb storage box from LIDL, some adhesive film and some paper to reflect the light back into the "funnel

Details

I had some small plastic storage boxes lying around and needed a way to deliver LED light to a watch. So I took the lid off one of the storage containers. The bottom conveniently is shaped a bit like a lense so there wasn't a lot of distortion interferring with the light from the LED spot. Then all I needed was some clear adhesive film to attach the spot to the outside of the container and then freehand cut a strip of paper to form a reflective layer inside of the container.

Total cost: less than 5€ for 20K+ Lux of energy with 0.7W input. The spot has a convenient female USB-A plug to use basically everywhere.

Suits my needs perfectly.