Addmotor is very shady with their replacement parts. They want you to buy ONLY buy from them. I have a Addmotor Motan M-150 P7, and Addmotor's replacement battery is $500.00 and they make you show proof of the ORIGINAL invoice.After monthsof searching, I found a replacement battery for the same bike for HALF the price! They build the batteries brand new right before sending them out.The place is in China, but if you order from them, you get the battery THE NEXT DAY. Turns out they have an american warehouse because they get so many orders from the U.S. For the 1st week, the battery fit VERY tightly. You really gotta struggle to get it on and off the bike. After a week of sliding it on and off, it now does it perfectly. The Battery is VERY strong and actually gives my bike an extra mile farther than the original one did. HIGHLY recommend this company to anyone needing to replace their original battery with an aftermarket one.