back-ups 1500 failures?

[Anonymous user]

I just had 3 back-ups 1500's (bn1500m2) fail during a single short power outage.  all 3 exhibit the same symptoms, they just shut down when the cord is pulled.  The batteries are fine, they are charged, and even pass the POST switch to battery with no problem.  two of these had been replaced in 2019 just months after purchase because they would randomly not startup from the power button without going through the reset process of unplugging them and disconnecting the battery... the third one did the same thing but i didn't bother getting it replaced as the replacements for the first 2 did the same thing.  All 3 are still under warranty so they are sending me 3 new ones, but i am worried about reliability of these after this triple failure.  note that i have 2 much older back-ups pro 1300's and other ups's on the same service that are working fine, and this outage was a simple power company disconnect and reconnect so there were no big surges or unusual events.