Dane.Kouttron

[07.10.23] An updated mountain e-bike

Time for a new E-Bike Project


The pandemic brought up a new generation of cycling, I opted to build up a 'less janky' e-bike.

A frame gets rescued


I rescued this abandoned frame from Cambridge, its a beautiful Cannondale Catalyst (3), but it  I rescued the frame back in 2018 but did not end up 'reviving' this until my street-ebike started to mechanically fall apart.




Battery Pack

In a previous life, at A123 systems, there were these battery packs for a server rack. While they are not terribly energy dense (they very much are not) they were *free* and comically abuse tolerant. The packs themselves are 12S4P A123 26650 cells, which nominally fits in the "36v" window at ~9.5Ah nominal. On a modern e-bike 390wh is not enormous, but the output rating (Fused at 100A) makes up for the difference. 390wh is best case 15 miles, but realistically with a 60A current limit comes in closer to 10miles without regen and with city-start stop duty cycle. The case itself is stellar, its an injection molded APS-PC plastic, and because the internal cell groups are sitting vertically, at the same height as an 18650, the pack can be used for a high energy Lithium Ion 10S Pack.

For mocking up a Lithium Pack, I made a coarse model of the case in solidworks [link]


Hub Motor

I had previously used front-wheel hub motors on e-bikes and while its super easy to install, the front forks of most bicycles really is not intended for ~1kw of force being torqued on them. By putting a


Hydraulic Disk Brakes

One of the most significant upgrades was switching from cable to hydraulic on my disk brakes. I opted for the shimano kit.

Controller

For the longest time I swore by the "long jason" controller. They do work remarkably well untill they dont. Unfortunatley long-jasons do not really exist in 36V variants, and nominally they are getting old. During the great "Kankagamus Adventure" we ran four long-jasons modified to run with the 36V nominal packs. [43.2v down to 35V undervoltage cutoff]. They work but the current limit is non-modifyable and set at roughly 60A DC bus-amps, which is approaching 2.4 KW of input power.

Onboard Charging

I wanted an onboard J1772 -> battery charger that did not occupy a lot of space or volume.





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Here's a behind the scenes look at my work space and some of the images that did not make the cut to be included in the write-up:


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