[Nut-upsuser] APC UPS wrong input voltage

Charles Lepple clepple at gmail.com
Sun Mar 4 19:16:57 UTC 2018

[please use reply-all to CC the list, thanks!]

On Mar 3, 2018, at 11:42 AM, Crispin Proctor wrote:
> Folks,
> I've asked this question on the FreeNAS forum but there are no ideas there as it looks like it's a NUT issue.
> Original question: https://forums.freenas.org/index.php?threads/apc-ups-reporting-wrong-input-voltage.60888/
> the nut driver is reporting the wrong input voltage. I am in the UK, 230V but it's reporting circa 108.
> If I connect it to the laptop and run powerchute it reports the correct voltage. 
> AFAIK, the driver is the correct one.

The short version is that you shouldn't have to worry about the reported voltages affecting shutdowns, but I would still test it anyway (using a power strip or other switch to keep the UPS grounded while cutting the mains). There is a single bit coming back from the UPS for each of the OL/OB and LB states, and the UPS makes the decision as to when it considers its battery to be low.

device.mfr: American Power Conversion
device.model: Back-UPS XS 1400U 
device.serial: 3B1519X22971 
driver.version: 2.7.4
driver.version.data: APC HID 0.96
driver.version.internal: 0.41
input.voltage: 108.0
input.voltage.nominal: 102

^^^ Note that the nominal voltage is also off. This means it is most likely a scaling issue in the NUT code, but it derives those numbers from data provided by the UPS (which is frequently formatted incorrectly).

If you stop the UPS service on the NAS, and run the following as root, what do you get in the log file? (You can press Ctrl-C to kill it after 30-60 seconds - it will loop.)

/usr/local/libexec/nut -a ups -DDD 2>&1 | tee /tmp/APC-230V-log.txt
gzip /tmp/APC-230V-log.txt

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