This product is no longer available for sale. The seller may be offering an improved version or it may be hanging out on the beach, enjoying the retired life.
This is the “Infinity Supercapacitor Sun Jar Project"
I made the Infinity Sun Jar Project to address one of the biggest weaknesses of solar garden lights. Normally they are powered by a single Ni-Cd battery that will invariably stop holding a charge after one or two years. This is mostly caused by the battery chemistry itself, and by the lack of a comprehensive charging setup for solar charging the battery correctly, either by over charging the battery in very sunny conditions. The battery also has a memory effect that over time can render the battery useless from an extended cloudy condition.
The Infinity Sun Jar addresses this problem not only by replacing the battery with a supercapacitor, but also by redesigning the supporting hardware at the same time. The supercapacitor that is supplied with the unit is a 350F 2.7v supercapacitor. The average lifespan of these units is 10+ years versus the one to two years average lifespan for Ni-Cd batteries. Another benefit of using the supercapacitor is it can more easily accept a charge then a chemical battery due to it's extremely low internal resistance, allowing the unit to accept a charge faster in overcast or partly cloudy days then a standard chemical battery can.
As for the hardware side, it's using a NCP1402 voltage booster circuit to boost the voltage up to the required 3.3v for a white LED. The NCP1402 is perfect for this application as it will self-start at just 0.9v and will then produce light via the LED all the way down to 0.2v. This allows us to use the full capacity of the supercapacitor instead of cutting off the power at 0.9v with a chemical battery. The beauty of supercapacitors is you can repeatedly drain them down to 0.0v without any damage to the supercapacitor. The included solar panel is tied into the circuit board, goes through a Schottky diode for reverse current protection in cloudy or nighttime conditions. The supercapacitor is protected from overcharging by using a zener diode coupled to the solar panel to produce a maximum voltage of 2.5v at 70ma. Once the unit sits in full sun for a full 12 hours (summer sun) the unit will operate up to 24 hours on a single charge. The unit automatically turns on/off by using the solar panel voltage to bias a mosfet connected to the on/off pin of the NCP1402.
You can see the completed unit in the photos above. It will be shipped to you with the circuit board fully assembled and mounted to the supercapacitor. The led will have the full length of the leads available for you to “twist” the led orientation to your specific application. The only two wires are from the solar panel to the circuit board. If you also look at the additional supplied photos you can use this unit in many different ways. You can make a conventional solar sun jar by placing the unit in a large mason jar upside down (the solar panel is too big to fit flat on a mason jar lid), a wire bound jar upside down, or even encase the unit in casting resin for the ultimate in shock and moisture protection.
You can follow the whole development process on this project by viewing the video series I made on my YouTube Channel:
Also the first picture with the black 500F supercapacitor will be the version you will be recieving with your order.
Once this last batch is sold out I will remove this listing. Thank you everyone for your support and I will be back with a new and improved version late summer / early fall. You can also keep up to date with my progress on my youtube channel:
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Located in New Castle, DE. Been playing with electronics for over 20 years. Always interested in renewable energy related electronics projects.