Battery packs, battery pack chargers, battery pack interfaces and adaptors of a cordless power tool system

A cordless power tool system comprising:

• a first power tool having a first power tool rated voltage and a first power tool interface;
• a second power tool having a second power tool rated voltage and a second power tool interface that is different from the first power tool interface;
• a third power tool having a third power tool rated voltage and a third power tool interface that is different from the first power tool interface and from the second power tool interface;
• a first battery pack having a first battery pack nominal voltage that is substantially the same as the first power tool rated voltage and the second power tool rated voltage and a first battery pack interface that is connectable to the first power tool interface to provide power to the first power tool, but that is not connectable to the second power tool interface or the third power tool interface;
• a second battery pack having a second battery pack interface that is connectable to the second power tool interface of the second power tool and to the third power tool interface of the third power tool but that is not connectable to the first power tool interface, wherein the second battery pack has a second battery pack nominal voltage that is substantially the same as the second power tool rated voltage when connected to the second power tool, and has a third battery pack nominal voltage that is substantially the same as the third power tool rated voltage when connected to the third power tool,
• wherein the second battery pack is configured to be coupled to the first power tool to provide power to the first power tool.