Electric working machine and method of activating electric working machine

An electric working machine comprising:

• an electric device;
• electric circuitry electrically connected to the electric device;
• battery packs to be connected sequentially to the electric device via the electric circuitry such that the battery packs are connected in parallel, the battery packs each including at least one internal relay to open and close an internal circuit;
• and
• a controller;
• wherein
• each of the battery packs includes a pre-charge circuit, the pre-charge circuit including a series circuit including a pre-charge resistor and a pre-charge relay and connected in parallel to the at least one internal relay;
• the electric circuitry includes external relays corresponding to the respective battery packs to open and close respective circuits connecting the respective corresponding battery packs to the electric device;
• and
• the controller is configured or programmed to:
• specify each of the battery packs as being a battery pack requiring a test process to examine opening and closing actions of the at least one internal relay or a battery pack for which the test process is to be skipped;
• specify each of the battery packs as a battery pack requiring pre-charging in which the pre-charge relay is brought into a closed state before the at least one internal relay is brought into the closed state or as a battery pack for which the pre-charging is to be skipped;
• in connecting the battery packs to the electric device,
• perform the test process on one or more of the battery packs that have been specified as requiring the test process to examine the opening and closing actions;
• and
• skip the test process on one or more of the battery packs that have been specified as being a battery pack for which the test process to examine the opening and closing actions is to be skipped;
• in connecting one or more of the battery packs that have been specified as requiring the pre-charging to the electric device,
• perform the pre-charging and then perform a first connecting process to bring the at least one internal relay of the one or more of the battery packs into the closed state;
• and
• in connecting one or more of the battery packs that have been specified as being a battery pack for which the pre-charging is skipped to the electric device,
• skip the pre-charging and perform the first connecting process.