The voltage regulating components (cost about four dollars) are here.
![](https://cdn.hackaday.io/images/2703581649081624451.jpg)
The overall shematic is here:
![](https://cdn.hackaday.io/images/1307511649081661504.jpg)
I have used this human powered light for more than 13 years. If you are in the "back of beyond," the super capacitors provide more longevity than batteries.
![](https://cdn.hackaday.io/images/5628191649081780795.jpg)
The quickly pieced together assembly (using parts I had on hand) is shown below.
![](https://cdn.hackaday.io/images/9768081649081914815.jpg)
Pro:
Long term reliability
Simple charge control
Stabilize power (protects against a few minutes of cloud)
A few watts of night power (think emergency light for an hour or so)
Con:
Bulky and costly compared to battery
They can be found at Amazon.com:
https://www.amazon.com/Jilin-3000F-Capacitor-Frequency-Ultracapacitor/dp/B08SM3NJF2/ref=asc_df_B08SM3NJF2/?tag=hyprod-20&linkCode=df0&hvadid=533426606375&hvpos=&hvnetw=g&hvrand=8054385460629123979&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9011703&hvtargid=pla-1460739104801&psc=1
Or Digi-Key:
https://www.digikey.com/en/products/detail/tecate-group/TPLH-2R7-3000SL60138/9930301