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.