I would suggest that if you decide to buy extra batteries online, be sure that you buy OEM batteries only. In other words, if you go Makita, buy Makita branded batteries. Be very careful, a lot of those "cheap" batteries you will see online are designed to look like their OEM counterparts,BUT they are not. Be careful and read the descriptions carefully and make sure what you are buying is "the real thing". This is my own opinion, but I'm a believer of buying, when possible, OEM batteries and parts. There is a difference!