Recently, I discovered that an inline UPS battery backup power supply is what you want to buy rather than a standby UPS battery backup power supply. The difference between the two is that the standby UPS will stop supplying power if the battery fails. On the other hand, the inline power supply will continue to supply power if the battery fails. This is a big difference as batteries are continually drained and charged throughout the day.
Eventually, the battery will fail and the power to the IT system will go dead when that happens. With an inline battery backup, the process of changing the battery can occur on a more scheduled and in a controlled manner.
The inline UPS units cost more than standby units. An array of possibilities is located here.