NAS thinks UPS battery is low

[ChrisG]

I have a BX750MI-GR powering a Synology DS920+ NAS, and connected via USB with the NAS set to hibernate when the power is low.

The NAS draws around 25W and when I cut to the power to the UPS it reports about 65 minutes of run time available, but then a couple of minutes later it says the battery is low and powers down.

I've tried powering a 58.3W load (couple of desk fans through a power monitoring smart plug) and the UPS ran it for 47 minutes, suggesting there is nothing wrong with the battery.

Could the UPS be reporting it's battery status incorrectly?  Is there a way to monitor what information it's sending?

[Teken]

You may consider this and report back success / failure:

1. Connect to Synology NAS via SSH

2. Edit /etc/ups/ups.conf

    pollinterval = 5
    [ups]
    driver = usbhid-ups
    port = auto
    ignorelb
    override.battery.charge.low = 20

3. Restart UPS service: sudo systemctl restart ups-usb

4. Check: upsc ups | grep battery.charge