This invention relates to the amplification of multiple nucleic acid target sequences. The method can include receiving, by a computing system, a request from a computing device for an electronic resource. A battery state of charge controller receives the difference between a battery state of charge set-point and the actual battery state of charge, and provides a battery power signal that attempts to maintain the battery state of charge at the set-point. When the part is pulled, the restricting member disengages from the carriage, the cover, and the housing and is detached from the apparatus.