APC Back-UPS BX1600MI Charging Inconsistencies and High-Frequency Noise When Off

[odinblue]

Hi,

I just bought a new BX1600MI ups with a battery date of September 2024. Charged it about 24 hours and plugged my medium-range home PC on it; the PowerChute software showed 90% and after some time 99%. It never attained 100% even after shutting off the ups. The ups works fine and after a power outage of 2 minutes it only goes down 2 or 3%, so no problem here, but it never recharges back to 100%, only to 99%, EXCEPT if I unplug the USB data cable and either connect it again to the same port or to another one. Then it immediately goes to 100%, but during the same session if the electricity goes off let's say to 97%, same issue, only 99%. Also in the morning when I turn it on it says 80%, so I remove the data cable, reconnect it, and boom 100%. The same applies when I log in to my linux machine (not powerchute, but apcupsd).

The other issue is that when the UPS is off but connected, it emits a very high frequency sound (I can't hear it, only my kids can); is this a problem?

Other than these two issues, everything works normally (no heat, no blinking, no red lights, fast recharge, etc.),

Thanks!

[Teken]

If the unit is connected to APC Power Chute software. Provide the event and data logs for the system for review.

Make a short video and provide a link as it relates to this sound. Lastly, I’m not clear what you mean by the UPS is off?!?

Are you saying the UPS is turned off via the power button while equipment is still connected to the rear outputs of the UPS System?!?