These are for back-up power for a major communications hub in Utah. There are two 750KW diesel generators with a 6000 gallon fuel tank at the site as well
It's estimated that if utility is lost and generators run out of fuel, the large battery banks would keep things running for about a week. Problem is, during summer the site would overheat in just a few hours with no (AC powered) air-conditioning.
The ups batteries are all connected in series. Each tray has four 12V batteries and there are ten trays...4X12=48X10=480VDC.