Voicecoil's red, fully rigid commuter

[docnjoj]

That is in agreement with the observed 20 mph of my extra wide rear Bafang on 48 V nominal in a 20x2" rear wheel! Thanks Mark and Voicecoils!
otherDoc

[Mark_A_W]

32kmh...at 48v.


That's just not fast enough. It'll need 72v to cruise at 45kmh....

[voicecoils]

New photos, the bike is running well. I've been running at various current limits with electrical power at 300-1200W. The battery box houses the controller, fusing and wiring. It's attached at the water bottle bosses and located by ally channel along the top. It's extremely solid, stainless steel with aluminium side panels. Great fabrication work from the Engine Whisperer

rear-drive-v2.jpg (137.98 KiB) Viewed 2050 times

[Toshi]

that battery box is looking good! secure mounting is quite the issue for homebrew e-bikes...

[voicecoils]

that battery box is looking good! secure mounting is quite the issue for homebrew e-bikes...

Thanks Toshi, With the water bottle mounts and a bit of bracing against the top tube, a solid mount is quite straight forward for a tough steel frame like mine.

The battery box with is surprisingly not an issue at all for pedaling and I've yet to knock my legs against it even though I do plenty of pedaling.

I'll get some close up photos of a few little details like how I turn the controller on and off externally, and how the side panel slides off soon.

I don't think the Bafang will stand the test of time so I'm already thinking of my future options. So far I haven't been able to bring myself to bolt that big 9continents motor to the front, the bike is already a handful to carry up quite a few steps in and out of my apartment. I carry it partially by the box and it hasn't bent or shifted out of alignment at all. If it did, I'd know because the crank clearance is so close!

[patrickza]

Good looking battery box! How wide is it, and does it feel the same pedaling or do you have to compensate?

[voicecoils]

Good looking battery box! How wide is it, and does it feel the same pedaling or do you have to compensate?

Hey Patrick,

The box is just a touch over 130mm wide. The Headway cells are 120mm wide without tabs and heatshrink so it's a snug fit!

Pedaling is not affected at all, I haven't spaced out the crank arms or anything either. I does feel odd if I put both feet on the ground. That's when the width of the pack is noticed but it rarely happens. When riding or stopped with one foot on the ground it's no problem.

[johnrobholmes]

What kind of temps are you getting on your motor now?

[voicecoils]

What kind of temps are you getting on your motor now?

I'm flirting with the devil and riding with 16-18A limited now (@72v lifepo4). Motor gets warm but not hand burning. I expect winding temps to be very high though.

Have not quantified it with a temp meter...yet, sorry.

[voicecoils]

after searching for ages, I finally have a grommet that fits perfectly around the wires that come in and out of the box. Trottle, Cycle Analyst, phase wires, hall sensors, and a positive DC pigtail from my battery pack (the 'key' of the system) all come out of that hole. Now they're sitting on rubber and water will have a hard time finding it's way in. The box has: one screw to pull the side cover off, one charge port on the right side, and the grommet'd hole for the wires. That's it, nice and neat.

red-bike-grommet.jpg (97.03 KiB) Viewed 355 times