A maintenance-free battery can be used on:

• Big Combo: 48 hours runtime
• Combo: 80 hours runtime

* Based on a 10% duty cycle. Runtimes may vary based on inflow of water.

** Older versions—before 2014—of the Basement Watchdog Special, Basement Watchdog Big Dog and Basement Watchdog Big Combo systems may not be compatible with maintenance-free batteries. Using a maintenance-free battery with an older system may cause false alarms. Please call us at (800) 991-0466, Opt. 3 for questions about compatibility.