Thursday 7 July 2016

Ghetto ebike: Wire Harness and things

I wired up a battery harness to connect two 24 volt batteries together, creating a 48 volt battery. Here is what I used:

2 x Male XT90 connectors
1 x Female XT90 connector
10AWG wire in Black & Red
Some pieces of 6mm Heat shrink tubing

Wiring it together is straight forward, you have to take note of the correct soldering as seen here

I recommend considering the use of anti-spark connectors for the motor connection. They can be bought here cheaply.

Powering up the ebike is a nice result after all that planning. It works! The colour display has nice information, not just clock and speed, but also displays Watts so you can see if you're pushing the 750Watt motor too hard (The motor will heat up). I have 9 power assist levels, and find anything past level 5 to be a thrill ride. The throttle control also lets me cruise without pedalling. I overtook a lady on a steep hill yesterday, she was gasping for breath at 3mph and I roared past at 25mph glancing back at her 'I hate you' smile. People gaze at me as I ride past - I notice that they are staring at the lipo packs mounted on the frame trying to figure it out. I may have to cover them and make them less obvious.

One thing I wish I had was manual adjustment of the pedal assist maximum speed limit. I can set it to one of three settings 15kph, 25kph, or 45kph however, I think I would like to set this manually to suit me, as I find my natural bicycle riding pace to be about 18-20mph and I find 25kph/15mph a bit disheartening when I have to pedal normally without power assist once I have passed this speed. I'm sure there will be commenters saying that 15mph is the law, but I'm cycling naturally at 18-20mph, I always have done. I'm quite a cyclist with years of riding. I once rode over 3500km from my home in Manchester to Naples in Italy camping every night at the side of roads and in fields. I have several bike tour experiences.
*Update: it does indeed let me adjust manually the assist mph/kph in single digits. All is good.

I am waiting for a power supply for my lipo chargers to arrive then I will probably do a full test of range and the display performance. All in all I am happy with the motor performance. I would like the chainring issue to be solved - I will 3D print a chain roller guide this weekend, and the Pedal assist limit to be changed. Those are my only gripes so far.

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