'74 LeTour electric conversion

[rjoe]

I just finished my first electric bike. It's a 1974 Schwinn LeTour that I got for $30 when I was in college. It just sat pretty much since then. It has two things going for it: indestructible Japanese lugged steel construction and the 25" frame, which gives plenty of room in the triangle. I upgraded to a 7-speed freewheel, too.

I'm running this motor:
http://www.motiondynamics.com.au/ge...36v/electric-bike/750w-36v-dc-gear-motor.html

The battery is two parallel sets of 5 Gen II Prius subpacks in serial for 36V.

The controller is a 40-Amp CT-660B9.

My first real test drive was today. Results are as follows:

30.1 mph top speed on a flat road with no pedaling
1308.9W peak
33.46A peak
1.6 Ah and 64.6 Wh for 3.87 miles at an average speed of 10.9 mph

So here is what the bike looks like today:

A video of the bike running under no load. Please excuse the breadboard potentiometer I made while the throttle magnet was loose.
[youtube]y84BZjpAC3Q[/youtube]



I was not impressed by the capacity of these Prius subpacks during testing. I could only charge up to about 6-7 Ah before the charger hit the -dV/dt condition which occurred around 43V, and then I could only get about 3-4 Ah discharge running it through some automotive bulbs at about 520 mA -- and this was with two packs, which should give 13 Ah. I did exercise the cells some, without improvement. But we will see what happens when I start riding it for real.

 

[dogman dan]

Nice hack! We don't see so much of it these days, so easy to get hubmotor kits from reliable retailers in the last few years.

Chances are, your only real problem is battery. If you stop driving some, the savings will soon pay for something much better for the battery.

 

[rjoe]

that's the plan


If the motor mount seems a bit overwrought, it's because I originally had it mounted on a rack that came with the bike (probably original) that sheared in half when I ran the motor the first time.