Hello, not sure how I add my purchase to the survey results, however here is my story. Purchased the Bafang BBS02 48v 750w kit from eLife Bike through an Ebay ad in April 2015. Date stamp on the drive indicated it was manufactured in January 2015. Item was shipped from China via FedEx. The kit arrived very quickly (Canada), in great condition and was exactly as expected. Communication with the seller was great with all questions answered quickly. Installation was a breeze.
Over the course of the summer 2015 (May, June, July, August) I logged about 1700 km commuting to work. Over the winter months the bike was stored in my unheated garage. Battery pack was stored in my house, and charge monitored at about 75-80% capacity. This spring I was not able to commute as much as I would have liked. Over the last few months I have added another 600 kms (total mileage ~2300 km).
Unfortunately a few days ago after riding the bike, I placed in the garage and forgot to turn off the battery. The next day while working in the garage on my car, the motor started crackling/sizzling for about 5-10 seconds and then I saw a puff of white smoke from the motor. Disconnecting and digging out the controller, I found the underside of the controller board fried. Not sure what caused it. Uncertain if related, however on the day of my last ride, the C961 display was showing an Err 12 code when pressing the pedal assist mode (ie, if in mode 1 and pressing the '-' button; or if in mode 6 and pressing the '+' button). At the time shutting the battery off/on cleared the code and allowed me to ride.
I am quite disappointed with the durability of the Bafang BBS02. I was expecting a much longer service life. I have since ordered a replacement controller from EM3ev and hope it will last much longer. Depending on the durability of this second controller I may reconsider buying a third. Although the controller is available for about $90 US. With exchange, shipping, duty and taxes, the replacement controller is costing me close to $200 CDN. If I have a similar issue, I'll likely experiment with a third party controller or look at a different system entirely (private message me if you know of a controller that works well with the BBS02).
When the BBS02 was working I was completely satisfied with it. From my experience however, I think the electrical components on the board are either of low quality or not properly spec'd for a 48v 750w system.