An interlock system and related method includes a battery assembly, and first and second modules. The battery assembly has first and second power contacts, and a sense contact. The battery assembly includes one or more cells, a standby circuit, and an interface circuit. The standby circuit electrically couples to the first power contact and the sense contact for generating a standby signal in the absence of a detected external electrical coupling between the first power contact and the sense contact. The interface circuit electrically couples to the second power contact and to the at least one cell. The interface circuit is adapted to electrically decouple the second power contact from the at least one cell as a function of the standby signal. The first module is attachable to the battery assembly and has a first pair of contacts adapted to couple with the first power contact and the sense contact of the battery assembly. The first module also has a second pair of contacts electrically coupled to the first pair of contacts. The second module is attachable to the first module. The second module has a third pair of contacts adapted to couple with the second pair of contacts. All of the contacts of the third pair of contacts are electrically coupled together.
