UPS or/and server Issues - Advice much appreciated

[Ceetan]

Hello all I am new here , so I hope i do not post this in the wrong space. also, thank you in advance!
I've had a UPS (Uninterruptible Power Supply) running for a while now, keeping the power on for my NAS
(Network-Attached Storage), and something quite unusual happened a few weeks ago.

The room was dark when this incident occurred, so I saw a flicker of light coming from the area where the UPS stood. My
nas, which is connected to the UPS, restarted. I'm not entirely sure what happened or how it transpired, but since then
there's been a power outage and the UPS DIDNT shut down the server the way it should have. SO now the serves is generally offline until i can get to the bottom of the mattter.

I have a theory that the cause might be a faulty and as far as I can tell there are strong indication. but I want to cheek if more experienced people think there's a significant risk of damage to the actual apparatus, given the circumstances I've described. What do you all think/Advice?



UPS: Model CP1500EPFCLCD
( Bought Ca 2018)

My NAS system
FreeNAS-13.0-Stable
MOBO: Supermicro X11SSL-CF with
CPU: Intel Core i3-6100
RAM 216GB Crucial DDR4 ECC 2133MHz (CT2K16G4WFD8213)
8 WD Red WD40EFRX 64MB 4TB in RAIDZ2
BOOT: 90GB Corsair SSD (Likley dead)
CASE: Fractal design node 804
PSU:EVGA SuperNOVA 650 G2
UPS:
CyberPower Adaptive Sinewave CP1500EPFCLCD

 

[Stephan]

Sometimes the batteries have gone bad (cooked by high floating voltage, water gone, bulging case) but the UPS does not notice it because self test is disabled. So when the next power glitch happens, UPS cannot switch to stable own power and load has to be dropped. Try to charge fully and then put 3-5 100 watt light bulbs as load on the UPS and see how long it lasts. Other possibility is near end of life capacitors in PSU, which are needed to hold voltages during brief outages like UPS switching from mains to battery and back. If those are too gone, the PSU will no longer tolerate a few milliseconds of failed mains. What do you think it is?