I'm looking for a replacement for my original battery from a bafang addon kit. That battery was a 48v 11.6ah (557wj). Is the 48v 14ah ultra slim battery (lg 3500 18650 cells) compatible?
You could replace it with any 48V lithium ion battery, but if the enclosure is different you may have to replace the mount also. If you have to replace the mount and can identify the connector used between the mount and the controller you might be able to save yourself some soldering. Common connectors used are xt60, xt90, anderson powerpole, etc. It is recommended that you buy from a reputable manufacturer that uses name brand cells and a quality BMS. EM3EV and Grin are good brands.