From: John De Armond
Subject: Re: Windy cars
Date: Sat, 11 Oct 2008 15:12:00 -0400
On Sat, 11 Oct 2008 09:52:56 -0500, "TXBill" <firstname.lastname@example.org>
>"William Boyd" <email@example.com> wrote
>> You could power a car with wind power indirectly. Battery bank developed
>> for recharging an onboard battery bank in an electrical powered car.
>> Such charge ability for the resupply battery bank could be charged with
>> wind and other alternate power development.
>Poppycock. The dream of starry-eyed idealists without any knowledge opf
>physics or mathematics.
You nailed it.
>> Chattanooga has a city tour bus fleet that is recharged after an estimated
>> 18 hour tour on duty.
>A publicity stunt with about the real-world practicality of a giant golf
You don't know just how hard you nailed that one, Bill. I happen to have one
of those buses until recently and parts for several more. Bought at the
bankruptcy auction, of course. I know the history behind the company and the
bus because I know the GUY behind it. Specifically Summerfield Johnson. Yep,
the Coke scion. He set the company up to take advantage of several federal
grants. When the grants ran out, so did the company.
As an electric vehicle, the AVS bus sucks bilgewater. Top speed of 40 mph. 2
KILOWATT-HOURS per mile at 20 mph. The Chrysler TEvan that would haul almost
as many people consumed around 500 watt-hours per mile at 60 mph. With
batteries stuck everywhere they could stick 'em (384 volts' worth), the bus
could barely make it through an 8 hour shift when the batteries were new. The
downtown Chattanooga "tour loop" (actually free tourist transport) is barely 5
miles long and the guys at the central garage have gotten REAL good at
changing battery pods after a few loops. The batteries are mounted in
aluminum chasses that are fork-lifted in and out of the bus.
The bus hammers the batteries so hard that they barely get 2 years' life out
of them. At the end, AVS tried to add a Capstone microturbine to the pig to
give it decent range but that failed miserably too.
The whole vehicle is a parts-bin affair. I doubt that there was an automotive
engineer in the company. They used industrial components with no
consideration for efficiency or weight or durability in an automotive
environment. Take the vacuum system, fer'instance. Unbelievably, even though
they had a compressed air system for other purposes including air bag
suspension, they still used air over hydraulic brakes.
For the vacuum pump they chose a Gast carbon vane unit - probably the MOST
inefficient pump made - and powered it with an off-the-shelf semi-open-frame 1
horsepower DC motor. Then they compounded the mistake by mounting the whole
affair UNDER the chassis right behind the front axle where it would catch a
good chunk of the road crud thrown up by the tires.
They used off-road heavy-equipment planetary hubs designed and rated for <20
mph on the drive wheels. Against the manufacturer's advice, of course. At 40
mph, the input shaft was spinning over 8,000 RPM which ate seals and bearings
and overheated the hub despite AVS and (mostly) the city of Chattanooga
spending bunches of money to find a suitable high speed lube.
I could go on and on but I won't take up more space and time. AVS was
designed to transport dollars from the feds to an already filthy-rich group of
businessmen and had little to do with transporting people.
When I got the bus, I had visions of making a little 100 mile range electric
motorhome out of it. I figured that I could cruise out to an RV park within a
100 mile radius, plug into the 50 amp outlet, recharge and after a couple of
days cruise back home. Either no or minimal fuel costs.
I'd planned on using the back half of the passenger compartment for more
batteries and the front half for living space. Then I did some electrical
measurements and chatted with other AVS bus owners on the net. I actually got
one of the very early buses that used a conventional truck drive axle and a
big DC motor instead of the later AC motor and planetary hubs. I could have
made it go faster than 40 mph but I could not have achieved 100 miles even
with batteries filling the entire interior. No matter how many ribbons I
tried to tie around that turd, it would still be a turd.
This 'un's a particularly funny Boyd-brain because the AVS buses were so
>The technology ain't there yet. Come back in 5 years and we'll talk some
Not for electric mass transit we won't. A bus is the absolute worst candidate
for BEV (battery electric vehicle) A bus full of passengers is FAR too heavy.
EVs now and as far into the future as I can see rely on very light weight and
excellent aerodynamics to achieve decent range.
Old rule of thumb. 1000 lbs of lead-acid batteries will take you about as far
as a gallon of gasoline in a passenger vehicle. Li and other high tech
battery technology will cut that by 2/3s if we're lucky. We might be able to
say that 350 lbs of Li batteries is equal to a gallon of gas. With tiny,
light weight, very streamlined (and consequently ugly) vehicles and a thousand
pounds of lithium batteries, an EV in the near future will probably do 300
miles to a charge. Forgetaboutit for mass transit.
Most likely the future will simply repeat history. Urban areas will be wired
again with overhead wires and buses will have catenaries to pick off the
utility supplied power. The buses will most likely contain small battery
packs so that they can travel short distances, such as around malls, off the
grid. Coincidentally, this describes a large city mass transit bus of the
'20s to a tee. But practical BEV buses will never happen. Especially when
"practical" includes "cost-competitive".
From: John De Armond
Subject: Re: Gas tubine generator
Date: Wed, 26 Mar 2008 23:46:41 -0400
On Wed, 26 Mar 2008 15:32:05 -0400, Tim <firstname.lastname@example.org> wrote:
>Neon John wrote:
>> On Wed, 26 Mar 2008 11:02:41 +0000, Mike <email@example.com> wrote:
>>>On the subject of TBO, Capstone units have an extremely extended
>> And if you believe that, I have some oceanfront land up here in Tellico to sell you.
>> Don't take my word for it. Ask any executive that you can find from the late great
>> AVS. That's the company that built electric urban buses. They tried to build a
>> hybrid NG fueled bus but went for the glitter of the capstone instead of the tried
>> and true spark or diesel engine. It bankrupted them. I have first-hand knowledge of
>> that one. Not the least of which from buying some of their assets at the bankruptcy
>> sale. According to folks from AVS that I've talked to, you could count the hours to
>> failure on your hands and have fingers left over.
>> There's a reason why all mission-critical small generators use some form of ICE. And
>> there's a reason why outfits like Capstone and that stirling outfit remain on the
>Great info but maybe you could explain to me how aircraft and larger
>turbines get longer lifes? I am green i am interested to know if this is
>an idea for home use?
The problem with the Capstone is that it's a blivit. (you know, 10 lbs of crap
stuffed into a 5 lb bag). A little unit that is small and light enough to be picked
up easily by a single man produces around 80kW (in the case of the AVS unit). To
pack that kind of power into such a small package, the bleeding edge of materials and
manufacturing state of the art must be pushed. High end ceramic and metals
technology, for example. Think of it as the F1 engine of the turbine world. It
makes a boat-load of power but not for long.
Larger turbines benefit from (relatively) conservative design and from decades of
engineering development. If you're really interested in this subject then I suggest
the book "Gas Turbine Handbook". Kinda expensive at >$100 but a very good read. A
PDF of the book occasionally shows up on Usenet and the Torrent network.
Is a small gas turbine suitable for home use? Not only no but hell no! At least not
unless you're looking for an unholy combination of noise, low efficiency, very high
cost (initial and maintenance) and low reliability. If you're looking for a cogen
electric/heat unit then look at the somewhat limited selection of IC-engine-based
units that are on the market. Or build your own.
York offered one during the last "energy crisis" that used a small, very low speed
natural gas fired engine to supply electricity, heat and AC (heat pump), all in one
nice package that looked like a conventional split unit condensing unit. It wasn't
commercially successful because it cost too much.
As for that WhisperGen, I frankly can't think of a problem that a unit that costly
can uniquely solve. Consider. The RV/mobile unit delivers about 800 watts of 12
volt electricity and about 19,000 BTU of heat in a package that sells for a whopping
$16,750. Those are New Zealand dollars. At today's exchange rate, that's 13,354.78
US dollars. Any idea how many diesel APUs one can buy for that kind of money? That
price is so far out there that the unit is irrelevant except perhaps for government
'crats spending other peoples' money.
Even Whispergen tacitly admits as much. Their only mobile "success story" on their
web site is an installation involving an ambulance. The ambulance didn't need the
comfort heat so basically some government agency spent around $13k for an 800 watt
generator. That same task (running the medical instruments) is normally accomplished
using a 200 amp "ambulance alternator" (commercial truck alternator) and a suitable
inverter. No more than $1000 even at inflated government prices.
This is the classic solution looking for the problem that will never exist.