Third party batteries are always a nightmare whether for a power tool, camera or some gadget and there are a lot of duds. I had a laptop wrecked by fake batteries, sold as genuine and unless you were an expert then nigh on impossible to distinguish from the real ones and some years back the battery in my PDA used for navigation just bulged, breaking of the rear cover and made a horrendous smell so tread carefully with unknown suppliers, Lithium can be nasty when misused. So if you want all cordless tools then you need to accept the cost of batteries otherwise get tools that plug in, paying £300 for three replacement batteries for a tool that if corded would not require that expense is not for me, maybe if I could pass the cost onto customers it would be different.