This is probably a really silly question... It looks like the battery is starting to go down on the pump; we're just past a month of pumping, and we're down to two bars instead of three on the battery icon. The manual says that a full rewind and prime is required. Do we have to change out the entire set to do this?? We're using the contact detach. Could I detach him, change the battery, rewind, insert the same cartridge, and prime through the detach, then reattach? Thanks in advance!!