An electric power tool comprises a main body supporting a tool and an electric motor housed in the main body for driving the tool. A plurality of first battery interfaces is configured to removably receive or attach a plurality of first battery packs and to electrically connect the plurality of attached first battery packs in series with the electric motor. A plurality of indicators is configured to communicate information concerning the respective conditions of the plurality of attached first battery packs. The plurality of indicators is arranged such that all of the indicators are simultaneously viewable by a user of the electric power tool.