Can I add a 2nd graphical touchscreen to an L5100?

Unfortunately you can not integrate any additional graphical touchscreen keypads with the L5100 Honeywell Lynx Touch wireless alarm system. However you can add the Honeywell 5828 and/or 5828V wireless keypads. Both units will chime but the 5828V will output voice annunciations on faults. Watch Sterling install a 5828 keypad to get an idea of what it looks like:

As mentioned in the video it is recommended to to get a Honeywell K0991 AC transformer to power the keypad and avoid the battery saving sleep mode. Once the keypad is installed you will need to program the device to the L5100 Lynx Touch. Follow along step by step with Sterling:

This should give you a good idea of what you will need to do in order to add keypads to your L5100 wireless alarm panel.

Although you will not be able to add the Tuxedo Touch and the Tuxedo Touch WIFI graphical touchscreen keypads to the L5100 you can use them with a VISTA series wired alarm system. Find out how many touch screens you can add to each VISTA panel here.