Welcome to my ENVIRONMENTALLY SAFE, FOREVER RECHARGEABLE SUPER CAPACITOR BATTERY PACK INSTRUCTABLE!!!
What's all the Hubbub, bub?
This circuit acts as a never-dying, forever rechargeable battery. If treated properly and with respect, it will live longer than you do! That's right! You will die before this variable battery does! Eerie, eh? The circuit employs about $90 worth of circuitry, but it sure beats buying batteries. I use this circuit every single day when I get home from work to listen to music. Depending on your input charging method (DC, solar, etc), charging can take only minutes. With this, I can listen to music out of my computer speakers at high volume for about two hours before having to re-charge. Use it to charge your cell phone. Use it to power your radio! Use it as a portable power supply! Wire it up to a flash light, or use it to power your halloween costume! The possiblities are endless! I am selling this in kit form! See the last page of this instructable for details.
YOU VARY THE OUTPUT VOLTAGE!
Need 3v? You got it!
Need 9v? You got it!!
Need 12V? You got it!!!
Need 34V??? You got it!!!!
HOW DOES IT WORK?
The circuit uses SUPER CAPACITORS, as opposed to batteries. Super capacitors are like other capacitors, only they have enormous power storage capabilities. Capacitors have two storage variables: Maximum charging voltage and capacitance (Measured in Farads). Capacitance is a measure of how much energy can be stored in a capacitor. A typical power supply capacitor or audio coupling capacitor would have a capacitance of around 0.0001 farads, which is relatively large. A super capacitor normally has a capacitance of between 1 to 3000 farads, which make them good substitutes for batteries! We are going to safely charge 2x 400 farad capacitors in series up to 5.4VDC, and feed that voltage through a DC-DC booster circuit. We are also going to employ a digital voltage display that will be able to read both the charge on the capacitor bank, as well as the voltage at the output of the DC-DC booster. Let's go over SOME of the pros and cons of super capacitors, shall we?
PROS OF THE SUPER CAP:
1) As long as you don't charge them at a voltage higher than they are rated for, or reverse charge polarity, super capacitors can have charge/discharge cycles of 500,000-1,000,000, or more!
2) If you charge a battery and leave it in the charger, you can deplete battery memory, and it will eventually die. The super capacitor will STOP accepting any energy once it is full.
3) The internal ESR (Internal resistance) is extremely small in a super capacitor. We're talking 0.01 Ohms or less. A typical battery has an internal ESR or 0.02 Ohms - 0.2 Ohms. Why does this matter? If means that you can potentially charge a super capacitor in seconds, providing you have some heavy duty power supplies. Batteries take longer to charge, and cannot discharge as quickly.
4) Batteries have a shelf life. If left fully charged on a shelf for years, you will pick it up one day and find it dead. Not so with the super cap!
5) Super capacitors give off no emissions, while all batteries give off some form of gas. You can't keep your car battery in your house, but you can keep your super capacitor bank in your house =)
6) If you cause a direct short along your super capacitors, they will not blow up or be harmed. They are made to do just that. However, immense heat will be created along the short, as enormous amounts of current will be very quickly dissipated. This is also a con, because the user can be burned if not careful.
7) They are environmentally safe.
8) There are so many pros and so few cons, but we don't have time to go over them all =)
CONS OF THE SUPER CAP:
1) If you made a super capacitor big enough to replace your car battery, it would likely be 10 times the size. Super capacitors have lots of energy storage, but need to be banked in series/parallel to achieve battery-like storage.
2) super capacitors normally have very low max voltage ratings, which means that you have to be very careful not to over charge them. As well, what are you going to do with a 2.5v capacitor? You have to place a bunch in series to keep doubling the voltage. However, when you add capacitors in series, you lose capacitance. The formula for series and parallel banking will be in the final step, so if you have time, have a look =)
3) While you need not worry about shocking yourself, as super capacitors offer so little voltage, you can burn yourself if you create a direct short on a fully charged super capacitor or bank of capacitors.
4) Super capacitors are more expensive than batteries.
THIS INSTRUCTABLE WILL BE BROKEN DOWN INTO 4 PARTS:
1) The Charging Circuit
2) The Capacitor Bank and the DC-DC Booster
3) The Digital Voltage Display
4) The Parts, the Math and the Conclusions!
If you are interested, most of these parts can be found in my ebay store, which can be found here: http://www.electroniclessons.com/
Check Out My Improved 1.5A 18 Watt Charger!