# Supercapacitor for power supply design?

Hi
I am new to electronics but I have studied the basics and the logic. I have 6 3000 farad supercapacitor from Maxwell(not the boost cap one) with a power rating of 3 watt- hour, so each capacitor holds about 10.8 kilo watts(3 watt x 3600 seconds= 10,800 watts). So I have been wanting to make a power supply out of these and two types have ran across my mind:
1. Turning them to a voltage multiplier type of circuit( so like a voltage multiplier but the capacitor is these capacitors). So I would have an output of 500 amperes(6 3000 farad capacitors in series would have a capacitance of 3000f/6=500f) and output voltage of 16.2 volts. For charging this power supply I will use a step down transformer connected to the mains with some circuit breaker, fuse, switch and ballast/ resistor at its input, the transformer will step it down to approximately 2 volts ac which then I will rectify with a bridge rectifier.
2. Putting them in parallel so I would have a total capacitance of 18,000 farad at 2.7 volts, and putting them in parallel with my power supply. So this works by charging the bank and the bank will discharge when fully charged. The power supply will be the same like the first design power supply. However this circuit seems very risky and I might need some feedbacks.

For your information I live in Indonesia and the wall outlet have 220 volts with amperage of ~20 amperes
So I have some questions which are:
Q1. Which power supply design is more ideal in terms of safety and efficiency? And how can I improve?
Q2. For power supply design 2, I believe I might need some "system" for timing the charge and discharge of the bank,what circuit or system should I use/ make? How about using relay? Or spark gap?
Q3. What should I do to avoid explosion of capacitor in both power supply
Q4. What components are recommended for the charging power supply and what diodes are recommended for the design one capacitor bank?

I already have the thick wires necessary for this since i know both systems deliver huge amount of power.

And please inform me if there is any mistake or anything wrong. Any input is very greatly appreciated, you don't meed to answer all question since i know is a lot and i don't want to waste anyone's precious time. Thank you so much for your time.

steveastrouk3 years ago

your carrots can supply 3watts for one hour, or, subject to the maximum discharge current limit of the cap....which is unlikely to be very high...more for less. If we assume they even could, they could supply 10kw for only 1

dikap123 (author)  steveastrouk3 years ago

thank you for your input! :) yes i understood they will supply 10 kw for only one second, you see, i am trying to make it charge and then discharge repeatedly so i have repeated pulse of 10 kw per second from each capacitor. Sorry if my english is not that good since i am from indonesia.

3 years ago

Whether you can depends on whether they can accept a 550 Amp discharge current, which is extremely unlikely. Check the specification

dikap123 (author)  steveastrouk3 years ago

thank you for your correction! So i rechecked the specification and it has "test current for capacitance and esr" of 100 amperes, what does it mean?

Here is the pdf: https://www.maxwell.com/products/ultracapacitors/d...

Please note my capacitor is the "bcap3000"

Thank you so much for your correction and your time, it is greatly appreciated ;)