On Jan 12, 11:12*am, bildan wrote:
On Jan 11, 6:56*pm, Martin Gregorie
wrote:



On Sun, 10 Jan 2010 12:47:53 -0800, Tom Gardner wrote:
2) If everyone turns their thermostats one degree closer to the outside
temperature, drives a smaller car, and switches off phone chargers when
not in use, will an energy crisis be averted?

My sister pointed out recently that British people tend to keep their
houses warmer than we did/do in NZ, so turning down the thermostat is not
a hardship - just put on a pullover over your T-shirt in winter.

Smaller cars is a problem for us in the trailer towing fraternity. My
main gripe with the current crop of electric and hybrid cars is that
nobody mentions towing, that I've seen anyway. There's one exception:
Aptera say NO TOWING up front. I guess the same goes for many of the rest
but they're too chicken to mention it.

Hungry chargers are just stupidly bad technology and should be banned.
Chargers that use no power[1] when they're plugged in but not connected
to anything have been around for at least 8 years, so there's no excuse
for selling one that burns power when its under no load.

Anyway, I just looked at four chargers I happened to have handy and
here's what it shows they burn when plugged into the mains and
disconnected from the things they charge:

18 month old Lenovo laptop PSU (65w o/p) * * * *0 * watts.
my much older Thinkpad 560Z PSU (54w o/p) * * * 1.9 watts.
iPAQ 3630 PSU (10w o/p) * * * * * * * * * * * * 2.0 watts.
2001 Motorola T250 phone charger (2.5w o/p) * * 0 * watts.

[1] I recently bought myself a power meter for a tenner from Maplins. It *
which reads to 0.1 watts, so a reading of 0.0 should mean 50 mW
consumption or less. These power meters are simple to use: they have a 13
amp plug on the back and a 13 amp socket on the front, so you just plug
them in between the wall and the device you want to measure.

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

I suspect the concept of "powered trailers" will pop up more
frequently. *This is not an unproven concept since the mining industry
has used it for years.

If you use a load cell to measure the push-pull loads at the trailer
hitch, the data can be used to control electric motors in the trailer
wheels. *If a glider *trailer housed a large battery, possibly charged
with a large solar panel on top and wheel motors, it could minimize
the loads imposed on the towing vehicle by essentially powering
itself. *The wheel motors would also provide regenerative braking.

The whole car-trailer combo then becomes a parallel hybrid which
permits the use of a much smaller and less powerful car. *The fuel
savings while towing would be small compared to the fuel savings
achieved by driving a small, fuel efficient yet tow capable car when
not towing.

The energy capacity of the trailer battery pack coupled to an inverter
could also power things like power tools and polishers when parked at
the airport.

The problem with EVs isn't power, it's on-board energy storage.

I have a friend who is a hybrid/EV enthusiast. He reckons the holy
grail is 40 mile range. Okay, adequate for most people buying
groceries or going to work, but completely useless for XC travel. We
need 1 - 2 magnitudes of improvement in energy density and 3 or 4 in
re-fueling time before you can reasonably talk about competing with
existing gas/diesel for hauling pilot/plane/crew to a site several
hundred miles distant.

That, or we turn I80 into a giant sized nuclear powered HO slot car
track :-).

Back to trailers: From fuel consumption numbers, I can back out that
my Komet trailer/glider has an effective fuel consumption of 120 miles
to the gallon at 60 - 65 mph on level road, no wind. Figure about 6
hp. Two or three times that under acceleration or ascending steep
grade. The point is: it's a small load. A decently capable EV could
tow it without difficulty.

-Evan Ludeman / T8