Electric power tool system

An electric power tool system comprises a tool main body (10), a battery pack (30) detachably attached to the tool main body and a first charger (50; 150; 250; 350) that charges the battery pack. The first charger is detachably attached to the tool main body and/or the battery pack. The first charger is capable of charging the battery pack while the battery pack is attached to the tool main body. The first charger is preferably cordless and contains at least rechargeable battery for storing energy to charge the battery pack.