The battery is VERY expensive, but I ordered it anyways because I needed a spare and I was given a nice discount so thanks for that :). The first battery showed up wrong - it was a 10Ah instead of the 14Ah. Took a bit of back and forth to return it and a few days later the correct one arrived. It’s not much better than the original 10Ah that the bike comes with, but it’s good.
Overall, I’ve had many problems with Surface604 since getting my shred in June. There was no assembly instructions with my bike, it was shipped with the wrong charger, the crank/bottom bracket stripped on my first ride, and recently the torque sensor failed. I was sent to a shop which doesn’t service bikes which they didn’t sell, and I’ve had to do a lot of my own research.. I guess in the end everything got taken care of. And the bike works well - just lots of glitches to deal with..