Adventures in Ultracapacitors

These things store a retarded amount of power.

Category:

Science & Technology

Tags:

• Ultracapacitor
• Powered
• LCD

[Galfonz]

Don't these amount to batteries that charge and discharge quickly?

[Tbird761]

@Galfonz Effectively, yes. The important difference is in how the energy is stored. Batteries store energy chemically. Because discharging and charging are physical transformations that can't be fully reversed without some degree of damage, they wear out after a few hundred cycles or so. Capacitors store energy purely as an electrostatic field between two plates.  There is no physical change; cycles are virtually unlimited. Caps storing this much energy are a relatively recent advancement.

[kingkennethJ]

What are the little wires between the capacitors? Are they diodes?

[Tbird761]

@kingkennethJ Indeed they are. Both are 5W zener diodes, just with one being 4.7V and the other 5.1V. Since caps charge purely from the current flowing through them unlike batteries and have no ability to handle being over-charged, it's critical to prevent them from exceeding their voltage rating. To do it properly (safely), what really needs to be there are PCBs with voltage comparators that cause a heatsinked power MOSFET to dump power when the pair's voltage exceeds 5V.

[kingkennethJ]

@Tbird761 Thank you. My last question is where did you get your buss bars holding the capacitors together?

[Tbird761]

@kingkennethJ The bars were fabricated from sheet aluminum. My dad has a metal shop, so I went over there and made some up. Do you need some? I could make and send you a set if you're in need.

[kingkennethJ]

@Tbird761 Well I was thinking about getting 12 of them and putting 6 in series and those in parallel with 6 more and putting them in my car. I've been looking online and I can't find anything that actually seems to be made for these. If it is possible to make me some that would be awesome. I hope we can work something out.