Nut upsuser - Dec 2007 - Driver: apcsmart, SMART-UPS 2200, battery.runtime status information?

Hello,

We have a APC SMART-UPS 2200 which gives the following status
information:

battery.alarm.threshold: 0
battery.charge: 089.0
battery.charge.restart: 00
battery.date: 01/10/04
battery.packs: 000
battery.runtime: 21180
battery.runtime.low: 120
battery.voltage: 52.95
battery.voltage.nominal: 048
driver.name: apcsmart
driver.parameter.pollinterval: 2
driver.parameter.port: /dev/ttyS0
driver.version: 2.2.0-
driver.version.internal: 1.99.8
input.frequency: 50.00
input.quality: 00
input.sensitivity: H
input.transfer.high: 253
input.transfer.low: 196
input.transfer.reason: T
input.voltage: 000.0
input.voltage.maximum: 000.0
input.voltage.minimum: 000.0
output.voltage: 228.1
output.voltage.nominal: 230
ups.delay.shutdown: 020
ups.delay.start: 000
ups.firmware: 80.14.I
ups.id: UPS_IDEN
ups.load: 000.0
ups.mfr: APC
ups.mfr.date: 01/10/04
ups.model: SMART-UPS 2200
ups.serial: YS0402211565
ups.status: OB
ups.temperature: 024.7
ups.test.interval: 1209600
ups.test.result: NO

What does the battery.runtime represent? It was my understanding that
this was in minutes, but this cannot be the case. Also what is
battery.runtime.low? Is there any documentation on this?

Also what defines when a UPS goes critical and a shutdown occurs?

Thanks

[...]
> What does the battery.runtime represent? It was my understanding that
> this was in minutes, but this cannot be the case.
VARDESC battery.runtime "Battery runtime (seconds)".

It is in seconds and without load, some devices report ridiculous long
times here. Complain to APC if you don't like/trust it, we only pass
through what the UPS is telling us.
> Also what is battery.runtime.low?
VARDESC battery.runtime.low "Remaining battery runtime when UPS switches
to LB (seconds)".
> Is there any documentation on this?