spinningmagnets said:
reddit member "anontrol" has reported that he bought two of the BBS02 units direct from China (through Ali-XX?), and has reported that both of them have a defective controller. The bad units are marked "C950 V4.0", though I suspect the version type is not a bad design so much as middle-men are selling factory QA reject units through third parties.
http://www.reddit.com/r/ebikes/comments/1xd06b/warning_defective_bbs02_48v_25a_bafang_8fun/
One of two C961 displays I got with 750W BB-02 kits started showing only "er 30" message ~2 seconds after booting :? , which a rep tells me means "communication problem" (fyi, that error message is not listed in motor or display manuals). Doesn't affect motor performance, but I can't see speed or PAS level since the error message takes over the display screen.
Same rep says C961 is "very reliable". But when I swapped out with my other identical display it worked fine. Ergo the problem is with that first display

I'm sending it back for the 8Fun/Bafnag techno-wizards to diagnose. Hopefully a new warranty replacement display will be forthcoming but I'm told C961 has been replaced/upgrade/had pigtail changed rendering my older one obsolete since the new display (& maybe harness) connectors are all different.
I know my <Nov. '13 all-black harness was since upgraded by 8Fun/Bafang to a multi-colored harness. Ergo, if I get a "new" display from Bafang, I'll have to hack into it's pigtail and splice connections to my older all-black display pigtail that does connect to the old all-black harness, or connect the new display to a new version harness and then hack that into the controller inside the motor or splice the new harness to the old all-black harness to keep the same harness/motor pin-out config.
Aaack. The downside of mfg.'s techno-upgrading is that, like trying to get a part for a cell phone - after ~3 months they're "no longer made".
Does anyone know of a Bafang parts supplier for things like C961 displays, speed sensor mounts -my old one broke (also upgraded recently I'm told), or harnesses?
Also, has anyone experienced "surging" when in PAS mode? I have. Applying Throttle seems to take it out. But it's a disconcerting up/down in power when pedaling without throttle. Puts a wrinkle in the PAS experience. Anybody got a fix for that
One tip re: shifting

: In the context of thumb/finger shifter and twist throttle: When cruising in traffic off the line, to upshift, I've learned to give a quick touch to a brake lever (just enough to get the electron message to the motor to pause it), at the same time upshift one click, all the while keeping w.o.t. (wide open throttle). It feels like an 8 speed automatic!
Downshifting on hills while pedaling, I stop throttling and downshift;; then w.o.t. again pronto; with just my continued pedaling the chain climbs onto the bigger gear easily and the motor kicks in just as the shift is completed. These shifting methods mean ~1 second delay in power, but are smooth and easy on the chain and gears.
One last suggestion for all onboard: Since most of the info on this forum is "for the good of the order", please be forthcoming with sources including web addresses, contact info. etc. when relating your new cool 8) must-have accessory items.
Thanks y'all.