From: Adrian Tymes (wingcat@pacbell.net)
Date: Tue Aug 26 2003 - 17:34:00 MDT
--- Mark Walker <mark@permanentend.org> wrote:
> I'm no engineer (as I
> am about to prove) but I'm not sure why you couldn't
> make an electric
> vehicle where at least some of the batteries pop out
> and are replaced by
> charged batteries. Suppose for example when you
> bought your car you leased
> your batteries from some company, say Exxon. (Gotta
> have something for the
> poor multinational to do). A decent electric vehicle
> will get about 100
> miles on a charge. Suppose on those occasions where
> you need to travel more
> than 100 miles you could pull into an Exxon station
> and a little robot would
> pull out your spent batteries and replace them with
> charged ones.
The standard keyphrase for this is "distribution
system". Put simply: how do you get those stations
set up in the first place? (Yes, there are gas
stations now, but how do you pay for refitting those
with the robots you mention prior to enough people
having these cars to make it economically viable? A
chicken-and-the-egg type problem.)
Much the same problem faces hydrogen-powered fuel
cells, which have much the same characteristics as
batteries (at least as matters to cars: fuel cells
breathe air, but this matters not in this
application; they exhaust water vapor instead of
nothing, but this also makes no diff to cars) except
they have higher power storage densities (thus
allowing longer trips between refuelling).
> As it is now, I've got to make a weekly stop at the
> gas station, so this
> setup would definitely be more convenient. I'd love
> to come home and simply
> plug-in.
Having operated an EV1 before they were scrapped, I
can tell you that your dream - in this regard - is
right-on. Granted, I had to plug in every few nights
(battery range over 100 miles, daily round-trip
commute under 50) or I'd be out of fuel, but it was
an easy habit to get in to. (I still remember a
friend's joke about the power meter: an 11-bar gauge
showing how full the battery was. "Bars of power"
sounded a little like I was powering it with cocaine
or similar, but what else could one call it, simply
enough for daily usage?)
One of the problems was, most people apparently did
(still do) much more than 100 miles of driving per
day, and in many cases, the only practical place to
plug in was at home. There were other chargers, but
not even 10% - probably not even 1% - as many per
unit area as gas stations, and charging was a slow
enough process that it really had to be at some place
you were going to be at for several hours - which
usually meant work or home. Battery swapping robots
would have solved the latter part of that, but then
you get into liability issues if a broken battery
gets swapped in which doesn't fail until you're 10
miles from civilization and 40 miles from a charger.
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