Boring Build: Bafang 750W / Giant NRS1

[kolby]

Long time lurker here, presenting my second electric conversion. After building up a Trek FX hybrid with a geared hub motor in 2012, I finally broke down and ordered a Bafang 750W kit with a 48V frame mount battery from lectriccycles. I find the hybrid quite uncomfortable at higher speeds, so I wanted to get a full suspension MTB this time and got lucky to find a Giant NRS 1 from 2001 on craigslist for under $500. I was worried about the motor not fitting alongside the suspension linkages, but it turned out to be the almost perfect bike for this conversion. The bottom bracket is 68mm, and there is no interference of any part of the frame with the motor. I ordered a 48t chainring, and it barely (by 2-3mm) clears the chain stay.

I prepared the frame before my kit arrived and did a quick install (under 30 minutes to get ready to ride) when I got my shipment. Unfortunately, while the ride was fun, I couldn't figure out how to change the settings on the new BBS02 head unit (C965), so I was hitting the default speed limit. I managed to find a link to the C965 manual on an Italian website and spent a few minutes changing settings. More fun.

Things I like:
- Super easy install (I got lucky with the bike)
- Quiet
- Fast

Things I don't like:

- Lack of documentation:
It would have been nice to find a user manual for the new head unit on the sellers website, but only the C961 version was available.
- Cluttered handlebar
The kit comes with a ridiculous mounting bracket for the head unit, and a separate mount for the control buttons. I used two metal brackets to attach the head unit directly to the stem, and will try to integrate the buttons into the unit as well. The throttle requires a lot of space and I had to move my XT shifters out of the way to clear the huge throttle enclosure (which is also quite uncomfortable, so it will have to be changed as well).
- Surprising amount of resistance when pedalling without motor assist.
- Lack of power consumption data in the head unit, so I can't check how efficient the drive is.





I'm planning on getting a 5Ah LiPo pack to use as a lightweight commute option.

- kolby

Edit: In case someone else needs the User Manual for the C965 unit: http://www.greengobikes.com/wp-content/uploads/2013/09/C965-800U-Specification.pdf

 

[skyungjae]

Though boring, I'm looking to do something similar as well. After messing with the GNG set up for a while, I just kind want something I can hop on and actually ride like a bicycle rather than feel like I'm jacking into the Matrix and riding an underpowered dirt bike.

I actually picked up a Jamis Dakar to clear the same style battery, but I like the suspension set up of your Giant. I accidentally bought a small frame Novara Float which was just too small to ride, so that ended up becoming my sister's early birthday present. :lol:

Anyhow, more pictures would be great. Like a side view. :wink:

 

[Paderolis]

It looks very nice, great job!!

 

[kolby]

Boring can be a good thing when it comes to installing a conversion kit. :wink:

I was looking for different bikes on craigslist, and also picked up a Rocky Mountain Element Sport, which also works great for this kit (the lectric cycles version supports 73mm BB sizes), but the Giant was 7 pounds lighter and a great deal for under 500. I couldn't find a Jamis Dakar in the right size at the time, but it was on my list. The Giant is a 20.5" frame, and bigger than I would normally ride, but I don't think the battery would fit in the smaller frame.

After clocking about 200 miles on this thing, I do however have to say that for me as a roadie (I used to ride over 10k miles a year), the Q-factor (distance between the pedals) of the kit is just too large (164 mm + two crank widths), and when I use it to exercise, my knees start hurting. If you're more of a MTB type you'll probably be fine, but my knees have had issues in the past, and I do want to use the bike for exercising as well.

Efficiency gets better as everything is breaking in, pedaling resistance without the motor is almost unnoticeable now.
Last night I did a 30 mile loop, averaging 22 mph mostly in PAS level 2, and had 3/5 bars left on the battery indicator, with some throttle fun thrown in for good measure (bumped into a roadie group ride ).

I will get some more pictures up when I get back after the holiday weekend.

- kolby