Abstract: One embodiment of the invention provides a UPS including a precharge circuit and a battery pack sensor electrically coupled to the precharge circuit. The sensor senses the presence of an extra battery pack. The precharge circuit includes: a first precharge contact; a capacitor having first and second leads, the first lead electrically coupled to the first contact; a second precharge contact electrically coupled to the second lead of the capacitor; a current limiting circuit having first and second leads, the first lead of the current limiting circuit electrically coupled to the first lead of the capacitor; and a third precharge contact electrically coupled to the second lead of the current limiting circuit. The UPS can further include an enclosure having a housing and a battery connector integral to the housing, the battery connector adapted to receive the first, second and third precharge contacts.

Abstract: An uninterruptible power supply (UPS) system using a battery pack may be potentially hazardous in its design, and in particular when users themselves connect or disconnect the battery from the UPS while the UPS is still active. A battery cap is provided that attaches to the battery to cover parts where the lead wires meet the terminals of the battery.

Abstract: An uninterruptible power supply (UPS) system using a battery pack may be potentially hazardous in its design, and in particular when users themselves connect or disconnect the battery from the UPS while the UPS is still active. A battery cap is provided that attaches to the battery to cover parts where the lead wires meet the terminals of the battery.