Mounting the BAFANG battery was a bit tricky. The battery is designed for mounting on the down tube using the water bottle cage mount. However, my 48V 17.5Ah (840Wh) Jumbo Shark Pack Battery is so large that I would have to give up both water bottle cages.
Instead, I mounted the battery on a rear rack. Although they make rear racks especially for e-bike batteries, my battery is so large that I couldn’t find an e-bike specific rack the battery would fit on. As a result, I had to repurpose an old touring rack for the job and make my own mounts for the battery.
While I like the battery on the rear rack there are two drawbacks to carrying the battery on a rear rack. First, it puts the battery weight (approx. 9 lbs.) high on the bike. And second, it places the weight directly over the rear axle. Ideally you want the weight lower and centered with a more even weight distribution on the bike for better handling. Nevertheless, carrying a battery on a rack is not uncommon and I will ride it this way for a while to see how I like it.