The new Electric Cessna 172

wrote:

snip old stuff


Most of what I was reading didn't seem to indicate that the goal is to
replace, but rather to compliment existing technologies, e.g. charging
applications.

http://phys.org/news/2012-10-sponge-...lectrodes.html
- Graphene

http://phys.org/news/2011-08-energy-...-electric.html
- SMC

Lot's of little techical problems in both of those articles.

The biggest is talking about recharging in minutes.

It is a rather simple calculation to calculate the current requirments
to recharge a device (doesn't matter battery or capacitor) to the full
energy level in a few minutes.

When you do that you discover that the size of the cable required so that
it will not vaporize due to the current density is as big around as your
leg with matching connectors.

Energy sources are rated in KWh and is equivalent to 1000 x V x A x h.

A typical electric car battery is around 30 KWh and 100 volts and 6 minutes
is 0.1 hours so:

30,000 / (100 x .1) = 3,000 Amps

To put the wire required in perspective, those big heavy cables on an
arc welder are good for a current of around 100 Amps so your charging
cable would have to be about 30 times bigger than arc welder cables.

I'm not saying it will (ever) power an airplane. Just looked
interesting and sometimes there are great discoveries that come out of
research, often in applications that were never part of the planned
research itself.

Yeah, that is usually the case.


Peace.