Re: ultracapacitors

["Peter VanDerWal" <peter_vanderwal@msn.com>]

>"Because the voltage drops so quickly you can't just parallel the pack.
>Putting the UC's in series with the pack is a possibility, however it
>has a few problems.  As I see it; you'll need a controller that I don't
>think exists yet.  One that can do regen (and somehow store the energy in
>UCs instead of the pack) AND that is rated way above pack voltage AND can
>handle a very wide range of input voltages.   Plus you'll need the
>contactors to switch the UCs in and out of series.  Plus you'll need a
whole
>bunch of those very expensive UCs"
>
>  Since we are talking blue sky here, I think we should speculate that
>  series switching and the controller are not major problems. Regen isn't
>  in my scheme in the short term because I haven't heard how to do it. As
>  to expensive, these are very expensive now, but it should be reasonable
>  to produce a unit for a 'reasonable' amount in production. And
>  production can be driven by the E power industry for power factor
>  correction.
>


Follow the thread.  This discussion was about how to store regen energy in
UCs.
If you have a lot of money;  batteries like Optima YTs are over 90%
efficient at storing energy (unless they are above 80% charged).   For short
term energy storage UCs are slightly more efficient, but I don't think this
justifies the added complexity and cost of using them.


>    "UCs are neat, but so are blue LEDs.  Just because it's a neat
>technology doesn't mean there has to be a way to use it in an EV."
>
>  I think this is a weird viewpoint. Anything that will reduce the
>  Peukert losses and Cheaply boost acceleration is worth trying.

Better batteries can do this almost as well for a lot less money and better
overall efficiency (the goal being to go farther on a charge)

> As to
>  blue LEDs, I just got an inexpensive color portable, and the 480,000
>  blue dots are neat. Nicer than the green ones.
>

O.T.  I'll bet your color portable doesn't use blue LEDs though.  Probably
uses an LCD panel with backlight and a color filter (like all the rest).

-snip-
>    "Just because they hold a lot of energy doesn't mean that they are
>particularly good at holding it or that they have a low ESR or even that
>they can be charge/discharge very quickly."
>
>  As stated earlier, the discharge rate is very fast and allows a lot of
>  Power/cu.ft.  They don't hold a lot of Energy; Range (energy) might be
>  two blocks on a UC alone. Quickly (power).


While I agree with this, I want to clarify my earlier statement.  When I
said UCs hold a lot of energy, I meant compared to regular Capacitors and
not to batteries.

And that's all we're really talking about here,   a capacitor that holds a
lot of electrons in a relatively small package (compared to normal
capacitors).  It doesn't do anything that you couldn't do with a whole bunch
of regular capacitors.