Re: Home made Hybrid

[m k <socalramblers@xxxxxxxxx>]

Why not buy a used electric car?  There was even a Concord wagon on ebay that went for $2500 or so with not even a thousand miles.  I came across a Renault (boo boo, hiss hiss) Le Car in Ohio that sold for about $300 bucks and needed batteries.  I'm in California so with the transportation cost several times the cost of the car, I had to pass.  You will never recover your time from such a conversion if you do it yourself.  To do it right with new parts, you're looking at $5000 plus the cost of the car.  Get a used motor and motor controller and you may get that down to $3000.

 

I used to work on electric cars back in junior college and we built a couple of electric go karts.  One car that was donated to the college was a '73 Mazda RX3 with the old RWD axle from the rotary drivetrain.  The mismatch in the gearing between a 7000 RPM engine and a 2000 RPM electric motor gave us a top speed of no higher than 35.

 

I've seen two types of homebuilt hybrids.  One uses a full set of batteries and a generator on a trailer, which charges the batteries while being driven.  The down side is that lead acid batteries can't be quick charged too often without the loss of capacity so your batteries will need to be replaced sooner than a straight electric.  The other is more complicated and more expensive, to have the generator provide electricity directly to the motor while pulling amps from a smaller pack of batteries for acceleration.  Either of these hybrids can get about 100 MPG and I've heard of over 300 miles on a charge.

 

The Prius and Civic hybrids use the batteries for acceleration and the engine at cruising speed.  The engine directly powers the car, but also provides electricity to the batteries so they never need recharging. 

 

Now how much time does it take to recover the cost of a conversion through saving on gasoline?  There's also no need for oil changes, smog, engine electronics, tune ups.  So there is a point where most people would save, but it would take years.  Buy one used and you'd probably start saving during the first year.

 

 

Michael Kelly

 

From: farna@xxxxxxx
Subject: Re: {SPAM?} Home made Hybrid
To: mail@xxxxxxxxxxxx
Message-ID:

There are several electric conversion sites. That's what you want to look at
first. The simple hybrid idea is to use a small generator, something quiet
like a Honda, to supplement range. Th batteries are still the primary power
source. The generator doesn't have to provide total power, just a bit more
than enough to pull the car at a steady cruising speed. Then you need to
start the generator when the batteries are 40-60% depleted. The generator
would be connected through a charging controller or large diodes that would
prevent current drain when the gen isn't running. Diodes are all that's used
on solar cells when overcharging the battery isn't an issue (like on the
little "battery saver" types). Of course you'd have to have some type of
on-board charger. That itself wil! l limit how much you can charge the
batteries while driving. But when you're stopped, the gen is still running.
So you're charging at stop lights. If you get on the interstate and cruise
at 55-60, the genera!
tor could be run and ideally would put out a little more power than the
electric motor is using, at least on level ground. You'd only be pulling the
batteries down when accelerating, passing, or pulling up hills. It takes
very little power to keep a car cruising, remember.

Of course that would be ideal. In a practical situation if you built a car
with a strictly battery range of say 60 miles, I think you'd extend the
range with the small generator to 90-100 miles in town, maybe 120-150 if you
have a long level cruise area. I think batteries to run that extra 30-80
miles would weigh and cost a lot more than the generator setup. Another plus
on the gen setup is that if you did run the batteries down a good bit you
could l! eave the generator running while you stopped for a rest. An hour
probably wouldn't get you more than another 20 miles or so, but if you
couldn't plug up the generator only uses a few gallons over 5-8 hours -- it
wouldn't be cost prohibitive to charge batteries while at work, overnight at
a motel, etc. Might not be saving much, but you wouldn't be stranded. A
Honda EN2500 uses a 5hp motor and produces 2300 watts (2500W is peak output,
2300W sustained), and will run 7 hours on just under 3 gallons (2.9) or gas.
Should be enough to!
replenish the battery pack at least by 50% over that amount of time.

If you had a generator that would keep up with total electric use you'd use
as much or more gas than the gas engined car. You'd have to keep up with
peak demand, not lowest demand. Though you could keep a few batteries on
board for dead stop take-offs, you'd be adding lots of weight with little
gain in efficiency. You'd have hybrid driv! e, sort of like a diesel
locomotive. that doesn't save fuel directly, it's a bit more efficient
because the electric motors can be made in such a way to provide lots of
traction without a lot of gearing like the diesel engines would need if
driving directly. For a car the weight of the generator in combination with
the driving engine would make it less efficient. I'm not so sure the combo
wouldn't work with something like a heavy load 18 wheeler though. I doubt
there would be enough efficiency gain to make it worth while. With a train
there obviously is.

On a home built hybrid the generator could easily be manually started. I
don't necessarily mean with a pull cord under the dash, though using a long
rope and pulleys it certainly could be done that way and not be obvious. An
electric start would be better, but I've not seen a small enough generators
with electric start. Anyway, what I meant was you could watch your charge
l! evel gauge and start the gen when needed. For short commutes you wouldn't
need it at all. If I had 70% charge left and was only a few miles from home,
I wouldn't use it.

I'm serious about the pull cord start though. I wouldn't think much at all
about putting a generator under the hood and using pulleys to route a cord
to an inconspicuous handle under the dash on a home built hybrid. As long as
it only takes 10-12" to pull, and was carefully placed relatively close to
the firewall, it would work fine. An electric door lock solenoid and/or
vac/electric heater control could even be rigged for the choke/gas (solenoid
would only work for choke) if cables weren't convenient.

Running the generator off a wheel is kind of like perpetual motion! It takes
as much power to turn the gen as you get back. Regnerative braking sort of
works that way, but you're getting back power that you used to accelerate.
Instead of throwing the power ! away as heat energy you use the electric motor
to slow the car (engine braking), and the motor is turned into a generator
while slowing to put that power back into the batteries. There's a rather
expensive control circuit for that. Worth it for a mass produced hybrid, for
a home built it complicates things and adds a lot to cost. Running the AC
compressor off a wheel instead of hte motor may have some merit, but you'd
be out of AC when stopped. If you're not in a lot of traffic that would
work. But I hate the fact that my wife's Volvo has an AC cut-off during
acceleration. On a hot day you just don't really want to go anywhere fast,
not until you get the car cooled down anyway! You could extend battery range
by having the !
generator tied to the AC -- it would charge some while running the AC also.
That would cut down efficiency a little, but would increase battery range.
May as well have an electric motor driving the AC though -- ! won't take any
more energy than running the generator, and the gen would be putting juice
back into the batteries when the compressor wasn't running.

Yeah, I've thought about it ;> My problem is the cost. It would cost a bit
more to build than a nicely equipped four cylinder car, and would take a lot
more careful thought and planning. I've got the concept down, would just
need to start shopping for parts. You could even make a LPG powered car
cheaper. I'm just reluctant to spend $2500-$5000 over what it would cost me
to build a mild hot rod. I paid $250 for a turbo four and five speed from a
Mercur XR4ti for what will likely be my next project. An electric motor and
accoutrements would have cost $1000+ for used items.

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com