How can I accurately monitor UPS runtime remaining using the "ups adv battery run time remaining" in PRTG with an ACP network interface card? The reported values seem incorrect, showing 1,200,000 instead of the expected 3 hours and 20 minutes.
The mentioned metric, as defined by the MIB provides a value in Timeticks:
| upsAdvBatteryRunTimeRemaining | 1.3.6.1.4.1.318.1.1.1.2.2.3 |
|---|---|
| Description | The UPS battery run time remaining before battery exhaustion. |
| OBJECT-TYPE | TimeTicks |
This is RFC-2758's definition for Timeticks:
The TimeTicks type represents a non-negative integer which represents the time, modulo 2^32 (4294967296 decimal), in hundredths of a second between two epochs. When objects are defined which use this ASN.1 type, the description of the object identifies both of the reference epochs. [...]
This means that you have the following alternatives:
- Divide the value by 100 to get a reading in seconds.
- Divide the value by 6000 to get a reading in minutes.
| However, I did a test, unplug the UPS, and then monitored the run-time both on the web interface and PRTG. The web interface showed a slow steady drop, while PRTG immediately dropped to 888,000. When I plugged the UPS back in, the graph did have a steady rise back to 1,200,000. So it seems their is a problem with values that are reported when the UPS loses line power. |
This is not a problem with PRTG but how the device actually behaves: Based on my personal experience, you'll see a very large drop as soon as the device enters battery mode. It will however slowly get more steady after a couple of minutes. This happens because the device takes some time under load to figure the actual depletion rate with the current load and provide an accurate estimation. As to why the web-interface behaves differently, only the vendor would be able to explain that.
On a side note, there are some ready-to-use APC sensors available here:
Disclaimer:
The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.
