Telecom’ Batteries are generally designed for Standby Power (Float Service), where the batteries are continuously €(float) charged by the Utility
power and only occasionally, in the event of a power outage, are the batteries discharged.
Generally, they’ll provide superior life in float
service (10 - 20 years), moderate
service (perhaps 1000 - 2000 cycles) life at 20%
depth of discharge (DoD), and poor service at 50% DoD (< ½ that expected at 20% DoD).
There's no telling how many cycles these used batteries have already undegone.
But, hey, they'll all be "free" amp-hours.