Input current reported is consistently zero #1

$ upsc ups
battery.capacity: 100
battery.charge: 100
battery.charge.low: 20
battery.charge.warning: 20
battery.current: 0.000
battery.mfr.date: ?
battery.runtime: 3932100
battery.runtime.low: 1200
battery.temperature: 40.38
battery.type: ?
battery.voltage: 23.14
device.mfr: Mini-Box.Com
device.model: OPEN-UPS
device.serial: PBSO4-LiFePO
device.type: ups
driver.flag.ignorelb: enabled
driver.name: usbhid-ups
driver.parameter.pollfreq: 30
driver.parameter.pollinterval: 2
driver.parameter.port: auto
driver.parameter.productid: d004
driver.parameter.synchronous: no
driver.parameter.vendorid: 04d8
driver.version: 2.7.4-695-gf15947f0
driver.version.data: openUPS HID 0.4
driver.version.internal: 0.43
input.current: 0.000          ⟵ This always appears as zero
input.voltage: 19.46
output.current: 1.789
output.voltage: 19.85
ups.mfr: Mini-Box.Com
ups.model: OPEN-UPS
ups.productid: d004
ups.serial: PBSO4-LiFePO
ups.status: OL
ups.vendorid: 04d8