Honeywell VISTA: Clearing a "System Lo Bat" (deprecated, updated video in description) - YouTube
Synergy Digital Alarm System Battery, Works with Honeywell Lynx Plus Alarm System, (Ni-MH, 7.2V, 700mAh) Ultra High Capacity, Compatible with Honeywell 300-06868 Battery - Walmart.com
Amazon.com: 2-Pack ZZcell Battery For Honeywell Alarm 300-03864-1, Lynx L3000, Lynx L5000, Lynx L5100, ADEMCO 300-03865, 7.2V, 1500mAh (NOTE: Please Check Part Number Before Purchase -Battery Connector - 2 Prong) : Health & Household
How Do I Clear a Low Battery in My Honeywell Vista P Series Panel? - Alarm Grid