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.
Here is the price breakdown so everyone can understand why this is not a cheap unit to make and ship:
- 500F supercapacitor - $10
- Components - $1.95
- Circuit Board - $1.00
- Solar Panel - $1.30
- My profit - $5.00
- Consumables - $4.75 (wire, solder, soler tips, flux, tape, etc...)
- Tindie & Paypal fees - $2.00
- Total price per unit - $26.00
I will only be shipping these to the United States and Canada. The customs forms and legalities are like wading through tax law. Sorry for anyone outside of the continental US.
You can follow the whole development process on this project by viewing the video series I made on my YouTube Channel:
This past weekend (10-27-2013) I have ordered all the parts to make another 40 units for the 2nd batch run. Thank you everyone that purchased a unit in the first run. I anticipate all of the parts will be here in 3 weeks, so the units should be ready in a month for shipping. I also have parts on order to build a reflow toaster oven that will make assembling these units much faster and look more professionally assembled.
Jan. 25, 2014, 4:53 p.m.
What is the output in lumens of this light?
Sept. 22, 2013, 7:13 a.m.
Where is the second batch and the schematic?
Aug. 22, 2013, 5:41 a.m.
Can you supply just PCB and components? It will make the shipping cost real. I can get the rest cheep.
Aug. 7, 2013, 2:12 a.m.
Did you forget to include the NCP1402 in the price?
Aug. 11, 2013, 5:18 p.m.
The price inculdes the assembled circuit board that has the ncp1402 chip installed. I just finished building the first batch of these units for sale and am testing them right now before putting them up for sale.
Rates to United States
|Shipping Rate||First item||Additional items|
|United States Postal Service: USPS Priority Mail Flat Rate Box||$6.00||$6.00|