We need to check the wiring to the battery. Here are some things to look out for:
1. Disconnect the panel's transformer from the wall.
2. Now we need to open the panel by removing the Trim Ring (or siding) from the panel and pulling up on the two tabs on the top of the Simon XTi. You will now see the battery and the rest of the circuit board. (This article is helpful in opening the Simon XTi).
3. There is a black connector that attaches the battery to the control panel, disconnect it.
4. Once you have disconnected the battery wait 10 seconds.
5. Now you can reconnect the battery to the panel.
6. You can now close the panel up and reconnect the transformer to the outlet.
7. Now you can check to make sure that the panel has cleared the low battery warning. Just press the "Gear Wheel" then press "Hear". If it says system "OK" you have successfully corrected the low battery warning.