[Nut-upsdev] usbhid-ups using wrong value for battery voltage for Pulsar Evolution 500?

[Charles Lepple]

I suspect that the battery is failing on my Pulsar Evolution 500 (it
is several years old now) but I can't seem to get a valid battery
voltage from the UPS.

The following tests were done using NUT 2.2.1, but I first noticed
this with the trunk, and reproduced it with the current
branches/Testing as well.

The only two values I have seen for battery.voltage are 120.0 and 119.0, e.g.:

$ upsc evo | grep battery      # full upsc output attached.
battery.voltage: 120.0
battery.voltage.nominal: 120

At first I wondered if there was a unit conversion error, but then I
pulled the plug, and noticed that the voltage did not go down (even
when the UPS shut off due to an apparently low battery - the charge
was much higher than it should have been, and there was no OB+LB
status, but that's another issue).

Then, I started looking into the MGE subdriver and the debug output:

mge-hid.c, line 344:
        { "battery.voltage", 0, 0, "UPS.PowerSummary.Voltage", NULL,
"%.1f", 0, NULL },
        { "battery.voltage.nominal", 0, 0,
"UPS.BatterySystem.ConfigVoltage", NULL, "%.0f", HU_FLAG_STATIC, NULL
},
        { "battery.voltage.nominal", 0, 0,
"UPS.PowerSummary.ConfigVoltage", NULL, "%s", HU_FLAG_STATIC,
mge_battery_voltage_nominal },

Here are some of the UPS.PowerSummary lines from running with "-DD":

Path: UPS.PowerSummary.PowerSummaryID, Type: Feature, ReportID: 0x26,
Offset: 0, Size: 8, Value: 1.000000
Path: UPS.PowerSummary.FlowID, Type: Feature, ReportID: 0x26, Offset:
8, Size: 8, Value: 4.000000
Path: UPS.PowerSummary.ConfigVoltage, Type: Feature, ReportID: 0x27,
Offset: 0, Size: 16, Value: 120.000000
Path: UPS.PowerSummary.Voltage, Type: Feature, ReportID: 0x2b, Offset:
16, Size: 16, Value: 119.000000

And some flow information:

Path: UPS.Flow.[4].ConfigFrequency, Type: Feature, ReportID: 0x14,
Offset: 8, Size: 8, Value: 60.000000
Path: UPS.Flow.[4].ConfigActivePower, Type: Feature, ReportID: 0x14,
Offset: 16, Size: 16, Value: 350.000000
Path: UPS.Flow.[4].ConfigApparentPower, Type: Feature, ReportID: 0x14,
Offset: 32, Size: 16, Value: 500.000000
Path: UPS.Flow.[4].ConfigCurrent, Type: Feature, ReportID: 0x14,
Offset: 48, Size: 16, Value: 4.160000
Path: UPS.Flow.[4].ConfigVoltage, Type: Feature, ReportID: 0x15,
Offset: 0, Size: 16, Value: 120.000000
Path: UPS.PowerConverter.Output.OutputID, Type: Feature, ReportID:
0x1c, Offset: 0, Size: 8, Value: 1.000000
Path: UPS.PowerConverter.Output.FlowID, Type: Feature, ReportID: 0x1c,
Offset: 8, Size: 8, Value: 4.000000

So I'm wondering if the "UPS.PowerSummary.FlowID" being equal to 4
means that the voltage in "UPS.PowerSummary.Voltage" is really the
power converter output voltage (Volts AC) instead of the battery
voltage (Volts DC).

Any ideas?

Could this be related to the "Evolution 650" bug mentioned in
mge-hid.c? (On the other hand, I suspect that if I added my model to
that function, it would only fix the battery.voltage.nominal)

Debug output is attached.

-- 
- Charles Lepple
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