Electric tool powered by a plurality of battery packs and adapter therefor

An adapter configured for detachably connecting a plurality of battery packs to a tool housing of a hand-held electric power tool, wherein each of the battery packs comprises a microprocessor and memory, and the adapter is detachable from the tool housing of the electric power tool, the adapter comprising:

• an adapter housing configured to be detachably latched to the first and second battery packs;
• a circuit disposed within the adapter housing and configured to electrically connect power terminals of the first and second battery packs in series;
• a controller disposed within the adapter housing and comprising an adapter microprocessor configured to receive signals respectively outputted from the microprocessors of the first and second battery packs, wherein the microprocessor of the first battery pack outputs a first signal in a first voltage range, the microprocessor of the second battery pack outputs a second signal in a second voltage range different from the first voltage range and the adapter microprocessor outputs a fourth signal in the second voltage range;
• a first signal communication path disposed within the adapter housing and configured to communicate the first signal from the microprocessor of the first battery pack to the adapter microprocessor, the first signal communication path being configured to shift a voltage level of the first signal in the first voltage range to a voltage level that is in the second voltage range suitable for inputting into the adapter microprocessor;
• a second signal communication path disposed within the adapter housing and configured to communicate the fourth signal from the adapter microprocessor to the microprocessor of the first battery pack, the second communication path being configured to shift a voltage level of the fourth signal in the second voltage range to a voltage level that is in the first voltage range suitable for inputting into the microprocessor of the first battery pack, and
• a third signal communication path disposed within the adapter housing and configured to communicate the second signal at the second voltage level from the microprocessor of the second battery pack to the adapter microprocessor.

An electrical apparatus, comprising:

• a housing;
• first and second battery interfaces disposed on the housing and configured to electrically and mechanically connect to first and second battery packs, respectively, wherein a negative battery terminal of the first battery interface is electrically connected in series with a positive battery terminal of the second battery interface, the first battery pack contains a first microprocessor and a first signal terminal configured to transmit first communication signals from the first microprocessor, and the second battery pack contains a second microprocessor and a second signal terminal configured to transmit second communication signals from the second microprocessor;
• a controller disposed within the housing and comprising a third microprocessor configured to receive the first and second communication signals respectively outputted from the first and second microprocessors via the first and second signal terminals, wherein in the state in which the first and second battery packs are respectively electrically connected to the first and second battery interfaces, the first microprocessor outputs the first communication signal via the first signal terminal in a first voltage range, the second microprocessor outputs the second communication signal via the second signal terminal in a second voltage range that is lower than the first voltage range and the third microprocessor outputs a third communication signal in the second voltage range;
• a first signal communication path disposed within the housing and configured to communicate the first communication signal from the first microprocessor to the third microprocessor, the first signal communication path being configured to shift a voltage level of the first communication signal in the first voltage range to a voltage level that is in the second voltage range suitable for inputting into the third microprocessor;
• a second signal communication path disposed within the housing and configured to communicate the third communication signal from the third microprocessor to the first microprocessor, the second communication path being configured to shift a voltage range of the third communication signal in the second voltage range to a voltage level that is in the first voltage range suitable for inputting into the first microprocessor;
• and
• a third signal communication path disposed within the housing and configured to communicate the second communication signal in the second voltage range from the second microprocessor to the third microprocessor without shifting the second voltage range.