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  • From: Clansgian AT wmconnect.com
  • To: homestead AT lists.ibiblio.org
  • Subject: Re: [Homestead] No battery 'Ultracapacitor' flashlight
  • Date: Mon, 10 Nov 2008 08:03:38 EST



> >I don't really understand this technology. The article doesn't give
> enough info. This is not a wind-up flashligh, nor does it use batteries.
> It
> lasts forever, without having to use and throw away a lifetime of
> batteries.

It uses a capacitor or bank of capacitors. It does not have batteries and it
last "forever" until the bulb or capacitor deteriorates with age.

Have you noticed that a radio or stereo will continue playing for a few
seconds when you turn it off or unplug it. You might even have noticed that
if you
turn a solid-state radio or stereo off while it is still plugged up, then
unplug it, and turn it back on, it will sometimes play for a few seconds then
go
dead until you plug it back up.

In the "power supply", the circuit which converts the 120V AC into low
voltage DC (which the device requires) employs one or more capacitors to
"filter"
the rectified AC.

A capacitor is a very efficient electrical storage device and can maintain
that storage for a very long time. When I was doing electronics bench work
(an
exticnt occupation), I had two enourmous capacitors there about the size of a
coffee can each, something like 22,000 mfd, and I'd charge them up from a 12v
DC source and use them to power the transistor radio for nearly a month.

Capacitors charge instantly. Even those huge coffee can capacitors took no
more than 45 seconds to charge.

With the advent of low power, low voltage LEDs for flashlights, this
capacitor based flashlight is quite feasible.

Here's the bit. This same principle crops up time and time again. Do you
have one of those LED flashlights that use batteries?? You can charge a
NiMHd
battery, AA or AAA, and that flashlight will keep a bright beam for months
(used a few minutes a day). The new technology that makes this flashlight
feasible is not the improved capacitor, it's the LED bulb, which IS a turning
point
technology. It won't be many years before that's all we use anywhere for
lights. Have you noticed those new traffic lights with LEDs, many times
more
clear and visible.

So why not have a whole house full of capacitors to store your solar and wind
generated electricity? It's probably coming, but they are ghastly expensive
compared to batteries and prone to failure.


James




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