Cor van de Water via EV wrote:
I am assisting someone to design a light 3-wheel EV that should be able
to run city speeds,
no more than 40 MPH is needed and the weight will probably be under 1000
lbs (plus occupants).
Not very aerodynamic but that should not be a problem at these speeds.
I have some idea of what components can be used - battery pack should be
Lithium to allow
a good range and the voltage can be selected to match the performance of
the motor/controller.
At a minimum (to maintain constant speed) I am estimating about 3kW of
power is needed,
for (leisure) acceleration and hill climbing I am estimating about 10kW
peak power.
Since price is an important design criterium, my inclination is to see
if one of the kits
to give Golfcarts higher performance would be sufficient - most likely
that or a similar
DC motor setup will be used for this design. This means probably a
battery pack of
between 48 and 72 Volts. If necessary field weakening to get the motor
the higher
performance needed for acceleration (like a kick-down) while normal
operation on
the nominal voltage will give the more steady-state performance at lower
current.
Any other recommendation for affordable yet durable motor and
controller?
It is expected that the vehicle must be capable to run 200k mi without
frequent overhaul.
I helped a guy convert a Vespa Ape 3-wheeler into an EV. These are well
under 1000 lbs. His was the "C" body, like the beige one pictured at the
bottom of this wikipedia web page.
http://en.wikipedia.org/wiki/Piaggio_Ape
Imagine a 1-person "egg" for the body, and a tiny pickup truck bed in
the back for cargo. It is a 1-front, 2-rear wheel design. The "rear
axle" and differential actually sits under the driver's seat. A trailing
arm on each side with a chain drives each rear wheel.
This setup leaves the space between the rear wheels completely open,
which is where the batteries went.
We used a golf cart motor, 36v pack of floodeds, and a Curtis 1204 golf
cart controller. Since the transaxle has a "floating" shaft, we used a
motor that had its own bearing on both ends (newer golf cart motors
usually have no bearing on the shaft end, and depend on the transaxle to
support the shaft).
It performed quite well -- better acceleration and top speed than a golf
cart; even better than the original whimsically small scooter-sized ICE
it came with! :-)
--
All children are born as engineers. Watch them at play. They're not
just playing; they're building and learning. They are engineering.
Then we get them in school and spend years squashing it out of them.
-- Geoffrey Orsak, Southern Methodist University dean of engineering
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
For EV drag racing discussion, please use NEDRA
(http://groups.yahoo.com/group/NEDRA)
