Power calculation vs actual reading on older Eaton UPS

[lensherm]

Hi @DartSteven ,

Thank you for this project and your work on the multi-UPS version. It is very much appreciated.

I have an older Eaton Powerware 9130 2000, which I know I should upgrade soon; however it looks like the power usage being shown in the GUI doesn't correspond to the actual value. I don't want to report it as a bug, just in case I'm completely wrong here, but here's the scoop:

1. I'm running my own NUT server and connecting to and getting data from this UPS via SNMP.
2. A number of variables provided by my older UPS are simply not reported or reported as zero. These include ups.realpower and ups.realpower.nominal
3. For now I'm using Nutify as a client connecting to my NUT server.
4. The power being shown by Nutify is exactly 290W most of the time, which I'm guessing is calculated by multiplying the 29% load by 1000 W (hard coded default?).
5. The actual power shown by SNMP and NUT is reported by output.realpower and is around 476 W

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With a little bit of help from Claude Code, analyzing my setup and your code, we came up with the following:

Root cause — three interrelated issues

1. output.realpower is not a recognized variable
   In nutify/core/db/ups/models.py, the DYNAMIC_FIELDS set lists every NUT variable Nutify knows about. It includes output.voltage, output.current, output.frequency — but output.realpower is completely missing. So the value is read from upsc but silently dropped when saving to the database because no column exists for it.

2. calculate_realpower() only checks ups.realpower, not output.realpower
   In nutify/core/db/ups/utils.py (lines 240-330), the function:

Checks for ups.realpower → your Eaton doesn't provide this variable
Since it's missing, falls back to calculating: nominal_watts × ups.load / 100
Looks for ups.realpower.nominal → also not provided by your Eaton
Falls back to a hardcoded default of 1000W (line 312)
Result: 1000 × 29 / 100 = 290W ← the wrong value you see
3. Power dashboard doesn't know about output_realpower
In nutify/core/power/power.py, the POTENTIAL_POWER_METRICS list also omits output_realpower, so even if it were stored, it wouldn't display.

The fix would need to
Add output.realpower and output.realpower.nominal to DYNAMIC_FIELDS in models.py
Update calculate_realpower() in utils.py to check output.realpower before falling back to the load-based calculation
Add output_realpower to POTENTIAL_POWER_METRICS in power.py
This is definitely worth a bug report. The core issue is that the IETF MIB reports real power under output.realpower while Nutify only looks for ups.realpower — and when it's missing, substitutes a rough estimate using a hardcoded 1000W nominal value.

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The output from upsc for my UPS is as follows:

battery.charge: 100.00
battery.current: 0.00
battery.runtime: 3300.00
battery.runtime.low: 180.00
battery.temperature: 0.00
battery.voltage: 113.00
device.mfr: Eaton
device.model: Powerware 9130 2000
device.type: ups
driver.name: snmp-ups
driver.parameter.mibs: ietf
driver.parameter.pollfreq: 15
driver.parameter.pollinterval: 3
driver.parameter.port: 192.168.79.101
driver.parameter.snmp_retries: 5
driver.parameter.snmp_timeout: 5
driver.parameter.snmp_version: v1
driver.parameter.synchronous: no
driver.version: 2.7.4
driver.version.data: ietf MIB 1.5
driver.version.internal: 0.97
input.bypass.current: 0.00
input.bypass.frequency: 60.00
input.bypass.phases: 1.00
input.bypass.realpower: 0.00
input.bypass.voltage: 240.00
input.current: 0.00
input.frequency: 60.00
input.frequency.nominal: 60.00
input.phases: 1.00
input.realpower: 0.00
input.transfer.high: 276.00
input.transfer.low: 140.00
input.voltage: 240.00
input.voltage.nominal: 240.00
output.current: 2.00
output.frequency: 59.00
output.frequency.nominal: 60.00
output.phases: 1.00
output.power.nominal: 2000.00
output.realpower: 476.00
output.realpower.nominal: 1800.00
output.voltage: 239.00
output.voltage.nominal: 240.00
ups.beeper.status: enabled
ups.firmware: INV: 1.29
ups.firmware.aux: Network Management Card V6.00 LE
ups.load: 29.00
ups.mfr: Eaton
ups.model: Powerware 9130 2000
ups.start.auto: no
ups.status: OL
ups.test.result: done and passed
ups.timer.reboot: -1
ups.timer.shutdown: -1
ups.timer.start: -1

[DartSteven]

Hi, thanks for the feedback. To be honest, I was already working on it. I was thinking about a renamer or remapper so that variables can be moved as desired. I have to finish a few things first (I'm trying to transfer the entire frontend to React), but yes, I've had it in mind for a while.

[lensherm]

Awesome! Thank you!