I went the rear rack battery route with a Bafang BBSHD mid mount 1000 watt motor on a Santa Cruz Bullit full suspension mountain bike . I attached the rack to the seat post. Two problems occurred: 1). I could not mount or dismount the bike because my right foot consistently got hung up on the rack. And 2). The battery and rack waggled the bike to the point that speeds below 5 mph caused me to weave down the road. I finally mounted the battery on the outside of the stem/bottom bracket downtube. Success!
