Tricumbent-Hybrid
Electric Recumbent Trike - Part 3 ...
June 2007
The previous
installment had the basic frame work completed back in the beginning of May
(07), although this is just getting posted in Aug (07) the work was done among
other projects through June.
As noted in Part
#2, the rear box frame looked like it could be stiffened a bit with additional
bracing.
The pieces shown
were scavenged from a bike that has yielded lots to this project already.
The placement of
the braces is such that it will add support for the Battery bag/paniers, while
keeping clear of the rear sprocket and hub assembly.
The battery
storage is a mix between the original fiberglass boxes made back in 2001/2002
for my very first Ebike project, and a sturdy saddle bag that came with a Llama
that we had for a few years (as a guard for our sheep from foxes and coyotes).
The boxes are cut
down to half their height and inserted into the bags to hold and protect the
batteries.
Below to the left
is a shot of the bags mounted with the Odyssey batteries inside and 2 (two) 7Ahr
cells that are wired in parallel (and then in series with the odyssey cells to
form a 36V string.
Above to the right
all four batteries are tucked away neatly and securely wired with more of the
AWG#8 cable.
Although this is a
terrible shot, it is of the a 36V/40Amp controller temporarily mounted on the
back of the seat of the trike.
With a simple test
drive at the top of my agenda, the motor is mounted and trued to the frame to
keep the chain from being thrown.
At this point
there are still no brakes (beyond dragging my feet), but the e-trike is finally
ready to roll.
Well it didn't
roll very far before the torque of the motor started to twist the mount around
the frame (throwing the chain, as I'd taken such care to avoid).
After successively
tightening the mount assembly more and more eventually it broke in 2 spots.
In an attempt to
salvage what I could of the main casting I opted to fashion 3 U-Bolts out of
1/4" #20 threaded rod as shown below the casting.
The point of this
image is not to show the hideous welds that marry the boom to the frame, but
rather that the main boom buckled either from the tension of the U-Bolt or the
strain of bouncing me, the batteries and the motor over some pretty uneven
terrain.
Regardless, the
rear frame assembly is near dragging on the ground and it is looking like this
project may well be completely trashed.
After considerable
review of the failure point, I thought that the basic framing could be savaged
by removing the weak length of unsupported boom and patching in a sturdier
section that would extend several inches inside the existing sections.
The idea didn't
take long to materialize, but finding the proper diameter length of replacement
pipe took several days.
At this point I
think that I was getting carried away with the additional framing.
The key issue
beyond reducing the flex of the frame was to ensure that there was still
adequate clearances for mounting the motor back into place.
The splice job and
framing have added a few inches to the overall length of the trike, and make it
look like some sort of land racer.
But the flex and
bounce is all but removed and I can start to re-assemble the electronics and
drive train.
As per usual, all
connections are carefully soldered, heat shrunk and taped to ensure no flakey
connections and to keep it dry from the elements.
As the progress
above was going on a 3rd 17Ahr battery was making it's way from Toronto with a
buddy of mine that was coming out for the season's opener of Bass Season.
Again, my
sincerest thanks to the Baron Harper
Group for sourcing and procuring said battery and to Steve for bringing it
out.
With a sturdy
frame, and everything re-mounted into place I was able to finally get some
testing under my belt.
The long and the
short of it is that the motor lacks any sort of low-end torque, even when the
throttle is cracked wide open the response is a cross between anemic and
lethargic.
But once the trike
hits about 5 or 6km/h it steadily gains speed up to about 15Km/h on smooth flat
terrain.
Hill climbing is
essentially non-existent, and with that I ordered a couple of larger motors and
matching electronics from TNCscooters.com.
The parts arrived
just as my wife and I were starting 2 weeks of holidays, so I made a conscious
effort to just forget that they were even in the shop. And they have been
sitting there ever since, now that I've gotten caught-up on some other details
around the farm, I hope to start testing the motors and making a final selection
before the summer is over.