When the lights go out, we often rely on Uninterruptible Power Supply (UPS) or “battery backup” systems to keep our computers running. From small and inexpensive home or office units to multi-megawatt data centre installations, these systems all perform the same basic task; they use batteries to supply power to computers and other IT equipment for brief periods when utility power is down. But that’s where the similarity ends - there are some important differences between consumer and enterprise UPS systems.