BBS02 750W internal friction

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!!Dean

Guest
I ordered a BBS02 750W from a Chinese seller on ebay to save $200 vs the cheapest I could find in the USA.

The unit arrived quickly and I've tested the electronics on a bench. All the electronic functions work, though I got an "Error 30" after playing with it for a while. I now get that error every time I power up, but the motor still spins; I just lose the use of the display. But all this is beside my point for posting.

When the unit is powered down, I put a crank on the post and spin the drive (as if I'm pedaling using my fingers) and it seems like it takes a fair amount of force. I would have thought that when pedaling without power, there would be minimal friction. So, in case of low battery, one can still pedal home.

I'm wondering if other people have encountered this friction (i.e. it's normal for no-power) or I got a bad unit (i.e. the chinese seller gave me a unit that failed quality tests at Bafang). It's tough to gauge proper amount of torque, I know, but I'd like to hear experiences from anybody.

thanks,

!!Dean
 

flymeaway

Well-Known Member
Without speed sensor feedback the unit will fault and return an error code. I have hand cranked both my 500w and 750w mid drives (on the bike with the power off) and have not noticed any significant drag. Yesterday I put a new wheel set on the E-Motobecane and rode it around without powering the mid drive and it rode like a non electrified bike.

Have you put the drive on your bike?

Court J.
 
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!!Dean

Guest
Hi Court!

Yes, I got the "Er 21" due to no speed sensor feedback during early testing. But the "Er 30" is something different. A google search hints that er 30 is a "wiring error". The error appeared after I tested if the system would run when the brake cables are unplugged. But after restoring the brake cable connections, the error message persists. (all plugging and unplugging was done with the batteries disconnected). This youtube shows a similar situation to what I see. I have no reason to believe the er 30 is related to the friction of the drive.

The drive is still on my bench. I'm not going to install it with this much friction (my ride is an Action Bent Tidal Wave II short wheelbase recumbent). I'm going to contact the seller to see if there's any chance for help there. After that, I may crack open the unit to see if I can fix anything. I'll keep everyone posted.