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Trek x caliber 8, Bafang ultra/M620


1 mW
Jan 26, 2020
Before this I had built a couple of 250W eBikes, but I allways wanted to build something with a litle more "umph" but still with a factory look to the bike.
Though of using the BBSHD, but I didn't really like how it hangs underneath the frame, so I decided to get the Bafang Ultra/M620 instead :)

It's been a long and partially hard process, but in the end I am thrilled of the outcome!
Only thing that is bothering me atm. is that I can't get the Bafang C18 display's SOC meter to work properly with a 14S battery, anyone got any ides?

Here are some pictures of the build, enjoy!

Before the build, a used Trek x caliber from 2018 (I think)


Made a jig and cut the frame to fit the Ultra engine mount


Fits like a glove :)



It took me a couple of iterations before I got the perfect fit for my battery box.


time for some battery build, 14S8P is pretty much the maximum amount of cells you could fit in this frame.
Each group is isolated with capton tape and then glued with a special kind of industrial glue.

Super duper tight fit! Sealed the battery with fast curing silicone and 3D printed TPU.

3mm aluminum plates on each side of the battery made everything super strong! Did some test riding and wow, I really like the Ultra!
Still need some fine tuning, and maybe a shunt mod, but the torque sense is amazing!