You really " need" 4 batterys and 2 chargers. 4ah minimum but preferably 5ah or 6ah. 5 batterys is my perceived minimum amount I "need." Using 2 power tools at once ( SDS and impact driver or Recip saw and angle grinder) you need 2 batterys but you need to 2 ready to go when they both are flat and a 5th for a work light. If I put my 4th battery on a worklight I have range anxiety. If you are using an SDS chisel all day then use 2 batterys before putting the 1st on charge (cool down time) and keep putting the cool one on charge as your last one goes flat. You will find to work all day you "need" 5 batterys and 2 chargers but 3 chargers is better.
