I have created 3 UnDPs for monitoring Emerson/Liebert UPS. These have been tested with GXT2-2000RT120 model UPS. These UnDPs include :
1. upsEstimatedChargeRemaining
2. upsEstimatedMinutesRemaining
3. upsSecondsOnBattery
In my setup I've created linear guages for #1 and #2. Advanced alerts can leverage these values as needed.
Please PM me if you have any questions.