Low Battery Duration

[Anonymous user]

+"Defines how long the UPS can continue to run on battery power after a low-battery condition occurs."+

What does this mean?

When do the clients receive the "on battery" message?

As far as I am concerned as soon as the UPS loses power, it should be signalling the clients that it is "on battery". Network Shutdown on each client then handles the shutting down after "X seconds on battery".

I fail to see where
"Low Battery Duration" comes into it.
If I set "low battery condition" to 5 minutes how would this affect the clients?
If I set it to 0 minutes, what happens?

Message was edited by: Mr_Darkman1

[Anonymous user · Accepted solution]

Thank you both for you answer. They answer my question perfectly. The two scenarios were exactly what I needed to see!

I could award points I would give you both "74"

[voidstar_apc]

>
As far as I am concerned as soon as the UPS loses power, it should be signalling the clients that it is "on battery". Network Shutdown on each client then handles the shutting down after "X seconds on battery".
>

Yes. In your case, as soon as one of two conditions occurs, PCNS will start a shutdown:
(1) If the UPS has run on battery for more than X seconds.
(2) If the remaining runtime that the UPS can provide drops below the "low battery duration".

In case of #2, the network management card triggers all attached clients including PCNS to start a shutdown.

Two examples.
Scenario A:
- Total runtime: 10 minutes
- PCNS shutdown after 3 minutes on battery
- Low battery duration: 5 minutes
Result: Three minutes after the UPS goes on battery, PCNS will shut down the computer

Scenario B:
- Total runtime: 10 minutes.
- PCNS shutdown after 6 minutes on battery.
- Low battery duration: 5 minutes
Result: Five minutes after the UPS goes on battery, PCNS will shut down the computer

Note: total runtime drops as the UPS' battery ages, so the low battery duration threshold provides a safety net to ensure your computers have enough time to shut down. If the battery can no longer provide at least the low battery duration runtime, the NMC will alarm that the battery is exhausted.

[BillP]

The best way to look at this is

Low battery duration controls the UPS shutting down
PCNS controls the server shutting down.

If you didn't configure PCNS to shutdown(installed the software but didn't configure it), the UPS would in turn gracefully shutdown the server assuming it had enough time. Many customers prefer to use the low battery duration to shut down their load. For example, PCNS only shuts down based on time ON battery. Some customers prefer to shutdown based on runtime remaining. As long as the low battery duration is high enough to give your servers enough time to shutdown, it will work properly. The lowest possible setting is 2 minutes. The bottom line is, it depends on your situation. If you can provide information such as your runtime, and how long you want to keep the servers up, we can provide you a recommendation on exactly how to configure it.