Basement Watchdog Emergency Sump Pump Battery

Once the acid is installed, your battery will be about 70% charged and will be ready to be connected to your system and utilized if necessary. However, you should still be connected to your backup system charger at all times in order to keep the battery fully charged at all times when AC power is available. 

Besides checking the battery terminals to insure that they are free of any corrosion and checking the acid level in the battery, the entire system, including your pumps, float switches and basins should be inspected every 3-4 months to insure they are performing properly and are free and clean of any debris that may impede their operation. Battery acid is only added once, at the initial start-up. Thereafter, if the cells are showing a low level, distilled water will be added. These batteries generally last a good 3-4 years before needing replacement. You could always take it to a local battery supplier or auto parts store to have the battery checked. They can test it and verify if it is ok and will still hold a charge or if it needs replacement.
Only certain battery backup systems are capable of adding a second battery to double the run time as the system controller must be configured to handle this type of connection. The Basement Watchdog model 24EP6 is the smaller of the two basement Watchdog batteries and would not be the recommended battery of choice even if your system was capable. You would need to consider the model 30HDC140S for such an application.

Unfortunately, it's not that easy. A 120 volt pump will not connect to a battery to provide backup in the event of a power outage. You would need to look at a BATTERY BACKUP SYSTEM or an AUXILIARY POWER SYSTEM.

You can use any deep cycle marine battery, as long as it is not maintenance-free. However, there are several advantages to using a Basement Watchdog battery. The Watchdog battery accommodates the system’s fluid sensor which will sound an alarm when the battery needs water…a very important feature, since a dry battery will not perform. In addition, Basement Watchdog batteries run longer per charge, and last years longer. A typical marine battery will last 2-4 years, while the Watchdog battery will last approximately 5-7 years. Basement Watchdog batteries are shipped dry (without acid) so they stay fresh on the shelf indefinitely, while wet batteries have a short shelf life.

Update 11/16/15: Basement Watchdog has changed this requirement around 2013 and their backup systems will now accept maintenance free batteries. Please refer to their updated installation manual for instructions on the proper method for this battery installation.