Re: short range hybrid product idea

[Lee Hart <leeahart@earthlink.net>]

Seth Bordeaux wrote:
> take 2 hubmotors and build them into the non-drivetrain wheels of an
> ICE. Place a small modular, and removable battery pack in the trunk.
> Asumming a top speed of 30 mph (but we all know speed really isn't an
> issue) how much would a battery pack weigh... to propel the modified
> ICE 10 miles to the grocery store?

EVs use on the order of 300 watt-hours per mile. 10 miles thus needs
3000 watt-hours or 3 KWH of energy. That's about 300 lbs of lead-acid
batteries, 200 lbs of nicads, or 150 lbs of nimh batteries.

> Flooded batteries are totally out of the question. This idea requires a
> removable battery pack, so you can use the space if you need it.

Not automatically. They are the most economical choice. Putting them in
a closed battery box, like a trolling motor battery, would solve the
spillage problem. Careful charger control and an external vent hose
solves the venting problem.

The main drawback of lead-acid (sealed or flooded) is the weight. You'd
have to move about six 50-lbs "lumps" by hand, or rig up some gadget to
make installation and removal easier. Perhaps an inexpensive automotive
engine hoist could pick it up out of the trunk as a single piece.

Nicad or nimh batteries help by reducing the weight. So would doing a
lighter car; a Geo Metro will only need half the batteries of an SUV for
that 10-mile range.

> Some modifications would have to be done to the car itself such as:
> Permanent hub motors in the rear (if front WD) wheels.

This is a challenge. There is no viable hub motor.

If all you want is a 30 mph electric, the electric motor can be pretty
small physically. The best bet might be to replace the rear axle with
one having an electric motor added that drives the differential's
pinion. If the car was front wheel drive to begin with, this means
finding a way to add a solid axle with differential (and motor) in the
rear. Some cars make this easy (already have a solid axle); others make
it nearly impossible.

If it's a rear wheel drive car, then the electric motor just needs to be
added somewhere in the driveshaft. There may often be room somewhere
along the tunnel, by cutting the drive shaft, and putting the electric
motor between two universal joints.

> Also a way to keep them from interfeiring with the drive train.

This part is easy.

> Cables strung through the trunk.

A few holes, some Anderson connectors, etc.

> A controller module.

Maybe mounted with the battery box?

> A dashboard indicator of power. (why can't it be wireless?)

Because you don't want to be viewing the state of charge of the
batteries in the EV next to you? :-)

It's not that hard to string a cable. If the situation is desperate, I
would prefer a system that superimposed the data on some existing 12v
wire.

> A charger module (not nessesary though if you use batteries with a
> built in charger

Since it is automatically a short-range EV and still hs its gasoline
engine, just leave the charger at home.

> some how a go pedal must be used without interfering with the gas
> pedal.

This could get interesting, as every car is different and they didn't
design them to make it easy. The simplest approach might be to simply
add a second accellerator pedal; one for gas, one for electric.

> makes the hubmotors act like regular wheels (unless you think regen
> is feasable)

Possible; it all depends on the type of motor and controller, and if it
is worth spending the money on it.

Other problems:

- What do you do for power steering, power brakes, heater, and air
  conditioning? With the ICE off, none of these work.

- Where does the 12v power come from for accessories (lights, wipers)?
  If you let them run off the accessory 12v battery, it will soon fail
  unless replaced with a deep-cycle version.

- Are you going to provide some means of recharging the batteries using
  the ICE?
-- 
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen