Light Electric Vehicle #1...
resurrecting
a trashed FS 2000...
To
the right is a Fortress Scientific FS-2000 Mobility scooter.
The
unit as shown was found in a scrap-yard in the winter of 2005. It took
considerable haggling to get the yard-master to eventually part with it, but
here it is.
The
tires do not hold air, it has no batteries, and it would appear that it has
spent a considerable amount of time outside as the electrical system is severely
corroded.
Not
knowing what I had procured I immediately searched out anything I could find on
the little buggy.
It is
equipped with a 1500Watt DC motor that is rated @ 36VDC up to 40Amps of current.
The
controller that is a proprietary Fortress design is only utilizing 2/3rds of the
available power at 24Vdc.
The
motor is powered by 4 brushes and is internally gear reduced in speed to 600RPM
(approx). But can produce considerable torque.
The
Controller (housed in the black box) provides smooth acceleration/deceleration
through analog "Ramp" circuitry prior to it MOSFet output stage.
The
chain drive to the rear axle appears to be quite heavy and powers a differential
that is constructed from quality castings and metal gear works.
The
majority of the water damage was within the user control-box shown to the left.
The
box was thoroughly dis-assembled and cleaned with a nylon brush and solvents and
numerous wires trimmed and re-soldered.
The
box offers Forward & Reverse as well as 6 speeds... I've found that I use
either the lowest or the highest speeds only.
The
unit was retro-fitted with 2 deep-cycle marine batteries as shown.
These
cells can power the rig for a full weekend of constant use.
The
unit shown here is how it looked after days of chronic refurbishment.
Initially
I just wanted to verify that the motor & controller worked, but once I
started to use this rig I knew it would not get chopped-up for parts as it's
just too much fun to have around.
For
the last month and a half it has been a constant source of annoyance for my
wife, as I would scoot between the machine-shop and the foundry, out to barn and
even ride it along side her as she would work out-side.
And
this is the reaction I get from everybody that tries it... Big smiles.
Some
how my buddy Ted looks surprisingly at home at the helm with a smoke in one hand
and beer in the other...
Given
that the scooter has enough of a novelty factor to save it from being
parted-out, I turned my mind toward some simple modifications that would
increase it's gee-whiz quotient.
To
the left are some foam parts that will be assembled into custom hubs that will
allow larger wheels to be mounted on the rear.
The
hubs are hot-glued together and test-fitted one last time before being cast with
high Silicon Aluminum alloy. The castings were left to cool very gradually in
the sand for several hours to aid in promoting a finer grain structure and
ultimately greater strength. (correction, after receiving
numerous emails and consulting my American Foundry Society manual slow cooling
does NOT promote finer grain structures as noted above while fast quenching in
water or oil does. appended Aug 2008)
The
castings were drilled, machined and tapped as shown to the left.
The
studs are 1/2" 13TPI all-thread that is threaded into the cast hubs, the
backs of the studs have nuts cinched down tight as I don't trust the Aluminum
(threads) to hold-up to any sort of abuse.
The
castings were faced flat on the lathe between centers for a true fit to the rim
of the tires.
The
axel is 3/4" steel, while the hub has a deep collar that extends it's
length to reduce the chance of it bending as the wheels extend out a few inches
further than they did on the originals.
The
larger boots have brought the top speed up to the point that you could actually
get hurt if you hit something, but provide a considerably smoother ride.
The
top-end speed gain was achieved at the expense of low-end torque. This isn't a
great concern given that the motor can handle 1/3rd more juice from a 36V
configuration.
That
will require a replacement of the existing controller.
I've
been slowly plugging away at learning how to program the PICAXE 08M
micro-controller, and eventually will develop a working motor controller for
this rig, but I doubt that it will be anytime soon. (Addendum 2008 - PicOx
V1.02c posted)
Over
the next few weeks (as time allows) I hope to marry the bike to the scooter.
With
the end result being a utility type vehicle with a bed at the back where the
seat currently is.
I
find that I do move quite a bit of gear between the shop and the foundry and a
small 2ft by 3ft box would be idea for moving tools, scrap, patterns and
castings.