A system for interconnecting a printhead cartridge and a cradle unit for supporting the printhead cartridge, the system comprising: an interface at which the printhead cartridge is removably engageable with the cradle unit, the interface comprising connections for connecting the printhead cartridge with a power supply of the cradle unit; and a power storage circuit incorporated in the interface for storing at least some of the power being supplied to the printhead cartridge from the power supply.