Posted on 11/05/2007 12:14:01 PM PST by Uncledave
Right. Caps have an equivalent series resistance(ESR), which determines the amount of current it can handle w/o heating up and exploding. The smaller caps always have a higher ESR, than the larger ones.
But on the the physics! Capacitors discharge exponentially when put to a load. That is to say, the lose their charge very rapidly! And if that load is, say, a short circuit, they lose their charge explosively (literally). How does one use capacitors for energy that must be used over a long period of time? I'd have to guess that some sort of voltage controlled impedance load that would vary the load between a very high state to an operating state to allow the capacitor to discharge in pulses of current or some such thing. Probably something completely different would actually work but that's my gut reaction. Still some science to be done!
That said, I live for the day I can hoist two middle fingers very proudly towards Mecca and tell the sandeaters I no longer need their oil.
Funny you should mention it.
Several years ago, a Taiwanese PC motherboard company experienced widespread failures of their boards out in the field.
It turns out that they had electrolytic capactors with 'youthful' mortality problems. Just enough to pass factory final test, and get into the hands of users and work for a while before going kaputt.
The capacitors were bought from a component manufacturer who offered a really low price. Too low. A young engineer, a capacitor whiz, had just come to that company from a competitor. He had brought with him the special formula for the electrolytic mixture--sort of like "Jack's Secret Sauce."
Problem was, he didn't have the full formula. He didn't know about an additional component of the chemical mixture that was necessary to keep the caps from self-destructing.
IIRC, it cost one or two companies their existence.
I’ll be sure to wait and see how these things stand up to the rigors of an automobile and be especially interested in the crash survivability data. Nothing like being in a car when you get T-boned and several million volts decides to let loose.
Most or all of these applications will feature a DC-DC regulated converter that isolates the ultracap from its load. When discharging, the converter ‘makes up the difference’ as the cap decreases in voltage.
However, the efficiency of power conversion, which may be as high as 90% at high cap voltages, does indeed decrease as the cap voltage decreases, so there is a limit where the converter has to say, “no more juice available—shutting down now.”
Regenerative recharging of the cap requires yet another DC-DC converter, hooked up opposite the the discharge one. Their mutual operation must, of course, be carefully controlled. [They probably have designs which can share components between the two functions to decrease cost and size.]
From what I read back then, it was a cause of very widespread board failure in many consumer electronic products (mobos, vcrs, vidcams, TVs), with many manufacturers not being open about the cause and unwilling to honor warranties because of the massive cost impact.
Awesome research. Sounds like a good prospect for more efficient delivery and storage of energy.
Finally, a taser worth it’s name...
The Teaser Taser?.............
bookmarking.
Please add me to this ping list!
Here are links to all seven articles in the energy series:
Article 1: Energy facts, certainties, and possibilities
Article 2: Government spending and its consequences
Article 3: Yes, growth DOES require more energy
Article 4: Dissenting from Mr. Gore
Article 5: The obstacle to oil independence
Article 6: A tankful of electrons
Article 7: A 21st Century GI Bill
Here’s what human ingenuity has come up with so far.
http://peswiki.com/energy/Congress:Top_100_Technologies_—_RD
Companies are already making ultracapacitors.
There are other technologies.
The Chevy VOLT is one of the best. Batteries with a small engine to recharge them.
There are motors out there that could make it so you could go thousands of miles before having to ‘fill up’.
Here’s one. It was invented over 30 years ago.
http://peswiki.com/index.php/Image:Bourke_30_Cubic_Inch_2_Cylinder_Engine_110.gif
Neat article. (your # 35)
I thought you were kidding. This was better’n a new Victoria’s Secret Catalogue!
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