NUT and APC BN900M

  • I just purchased an APC BN900M and connected it to my PfSense machine. I installed the NUT package and see no driver entry for APC UPS's. How to I get the NUT package to recognize the UPS? I tried all the listed drivers and they all came back with messages such as "failed to receive status".


  • I believe that it is a USB unit, so it would use the default usbhid-ups driver.

    Try running "usbconfig dump_device_desc" to see if the device shows up. Note that in rare circumstance, it is possible that you will have to reboot after you attach the usb cable.

    You can find a lot of useful debug information in the NUT package thread here

  • It shows up now! Here's the section of the dump:

    ugen0.2: <back-ups ns="" 900m="" fw932.a4="" .d="" usb="" fwa4="" american="" power="" conversion="">at usbus0, cfg=0 md=HOST spd=FULL (12Mbps) pwr=ON (2mA)

    bLength = 0x0012
      bDescriptorType = 0x0001
      bcdUSB = 0x0200
      bDeviceClass = 0x0000  <probed by="" interface="" class="">bDeviceSubClass = 0x0000
      bDeviceProtocol = 0x0000
      bMaxPacketSize0 = 0x0040
      idVendor = 0x051d
      idProduct = 0x0002
      bcdDevice = 0x0090
      iManufacturer = 0x0001  <american power="" conversion="">iProduct = 0x0002  <back-ups ns="" 900m="" fw:932.a4="" .d="" usb="" fw:a4="">iSerialNumber = 0x0003  <4B1647P27964  >
      bNumConfigurations = 0x0001

    Now, when there's a power failure what can I expect to  happen? I'm familiar with APC's PowerChute for Windows but it doesn't appear there are any options here I can configure…</back-ups></american></probed></back-ups>

  • @nipstech:

    Now, when there's a power failure what can I expect to happen?

    When the UPS reaches a low battery state, the UPS will signal NUT and NUT will initiate a shutdown.

    Given the time required to shutdown a Synology, you may wish to adjust the percentage or time used to determine that the battery is low. You can do this by configuring the UPS itself, or configuring NUT (recommended). See the doc for ups.conf for details on configuring NUT.

    I use the following for the system supporting my Synology:

            override.battery.charge.low = 20
            override.battery.runtime.low = 300

    Hope this helps.

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