The Basement Watchdog Maintenance Free AGM Battery – Backup Sump Pump Power (BW-27AGM)

Protecting a basement from power outages starts with a reliable, maintenance-free power source. The Basement Watchdog Maintenance Free AGM Battery (BW-27AGM) is designed to provide standby support for a range of Basement Watchdog sump pump systems without the need to add battery fluid or distilled water. This sealed AGM design is built for long-term, worry-free operation, letting you focus on what matters most when weather turns rough.

Maintenance-free by design

One of the most meaningful advantages is that there’s no fluid to mix or monitor. The AGM battery ships ready to install, reducing routine maintenance while delivering dependable backup energy during a power outage. Its sealed construction helps minimize corrosion risk and makes installation straightforward for most common Basement Watchdog configurations.

Real-world use and versatility

During heavy rains or utility outages, a standby battery keeps your sump pump ready to respond. The BW-27AGM supports multiple Basement Watchdog configurations, including the Big Dog, Special +, and Emergency lines, helping you keep sump water levels in check even when the power is out. The design supports intermittent operation for days in many setups, translating into longer windows of readiness during extended outages.

• Up to 40 hours of protection for the BWD12-120C+ Big Dog system (10% duty cycle).
• Up to 48 hours of protection for BWSP+ and BW4000-family systems (10% duty cycle).

Beyond these scenarios, performance scales with the system, giving you more extended protection for certain configurations—up to 80 hours for the BWE and CITE-33-based combos when duty cycles stay within the specified range. This means longer standby readiness in real-world basement conditions, especially when power restoration takes longer than expected.

• Up to 80 hours of protection for the BWE and DFk961/CITE-33 setups (10% duty cycle).
• Intermittent operation for days across many Basement Watchdog configurations.

Compatibility and safety notes

Older versions of certain models purchased before 2014 that include the Remote Terminal can use the Maintenance Free/AGM Battery. However, using a maintenance-free battery with some older non-compatible systems may trigger false alarms, so it’s wise to verify compatibility before installing.

Why consider this option

While nothing can replace a robust backup plan, a maintenance-free AGM battery offers peace of mind with easy installation and stable standby power across a range of Basement Watchdog configurations. It’s designed to be a practical, ready-to-use power source when you need it, turning a weather-related outage into a manageable challenge rather than a crisis.

Note: This description highlights product features and typical use cases. Actual results depend on your specific sump pump system and duty cycle conditions.