We have 10 computers at the office all on separate UPS's. we also have about 10 dead UPS's (sealed batteries are dead) laying about the office.

Is there any reason why we shouldn't buy a 300 amp/hour deep cycle battery, similar to what is used on solar installations, and take those 10 cheap UPS's with dead batteries, pull out the batteries and wire them all to the deep cycle battery. Then put a charger on the deep cycle battery. Shouldn't the deep cycle battery run all those UPS's for a good amount of time in case of a power outage?

Been looking around the Internet and wondering why this isn't done.