At long last I was finally able to upgrade my battery. When originally ordering my bike I made the mistake of not getting the 21Ah battery. The bike is awesome and many times I was limited with the smaller battery. Not anymore. The extended range has been very helpful! If you’re debating which way to go, my advice is to go with the bigger battery. The extended range/power can be helpful for heavier riders, terrain with elevation change, and most importantly allow you to stay in pedal assist level 7 for longer.