The best battery backup kit for a sump pump depends on whether you need a complete kit, an add-on backup pump, an inverter system, or a compatible battery component. For most homeowners, the right choice comes down to whether the existing sump pump is still reliable, how much room is in the sump pit, and whether the backup system needs to pump water directly or power the current pump during an outage.
This guide compares four approved sump pump backup options: a complete primary-and-backup system, an add-on battery backup pump, an inverter-style backup system, and a deep cycle AGM battery. Each one fits a different type of battery backup kit setup.
Quick Picks
- Best overall for a complete sump pump backup kit: The Basement Watchdog Big Combo CONNECT Preassembled Primary & Battery Backup Sump Pump System, because it is the best fit for buyers who want a more complete primary-and-backup setup.
- Best add-on backup pump kit: WAYNE ESP25 / ESP25N Battery Backup Sump Pump, because it suits homeowners who want to add backup pumping to an existing sump pit.
- Best inverter-style kit: Pump Sentry 822PS Sump Pump Backup System, because it is designed to provide backup power to a compatible existing AC sump pump.
- Best supporting battery component: Renogy Deep Cycle AGM 12 Volt 100Ah Battery, because it can support compatible backup kits that require a separate deep cycle battery.
The Basement Watchdog Big Combo CONNECT Preassembled Primary & Battery Backup Sump Pump System
A preassembled primary and battery backup sump pump system for homeowners who want a complete backup kit approach. Check current price
The Basement Watchdog Big Combo CONNECT Preassembled Primary & Battery Backup Sump Pump System is the strongest fit if you want a more complete kit-style setup. It suits homeowners who are replacing an older sump pump or want primary pumping and backup pumping planned together.
Best for: Homeowners who want a full sump pump and battery backup system rather than only a separate backup part.
Main advantage: It gives buyers a more complete system path, which can be easier than trying to match a primary pump, backup pump, controller, and related parts separately.
Main limitation: It may be more than you need if your current primary pump is already reliable and you only want a backup add-on.
WAYNE ESP25 / ESP25N Battery Backup Sump Pump
An add-on battery backup sump pump for homeowners who want backup pumping beside an existing primary sump pump. Check current price
The WAYNE ESP25 / ESP25N Battery Backup Sump Pump is the best fit for homeowners who already have a working primary sump pump and want to add backup protection. It is more of an add-on backup pump than a full sump pump replacement system.
Best for: Homeowners who want a dedicated battery backup pump for an existing sump pit.
Main advantage: It provides a separate backup pumping path when the primary pump cannot run during a power outage.
Main limitation: It still needs proper battery support, installation space, float switch placement, discharge planning, and compatibility with the existing sump setup.
Pump Sentry 822PS Sump Pump Backup System
An inverter-style backup kit for powering a compatible existing AC sump pump during outages. Check current price
The Pump Sentry 822PS Sump Pump Backup System is a different type of battery backup kit. Instead of adding a second pump, it is designed to provide backup power to a compatible existing AC sump pump.
Best for: Homeowners who want an inverter-style backup path for a current sump pump that is already suitable for the job.
Main advantage: It can help the existing pump keep running when utility power fails, provided the pump and battery setup are properly matched.
Main limitation: Compatibility matters. Pump startup demand, running load, battery size, charger setup, and installation conditions all need to fit the system.
Renogy Deep Cycle AGM 12 Volt 100Ah Battery
A deep cycle AGM battery option for compatible sump pump backup kits that require separate battery storage. Check current price
The Renogy Deep Cycle AGM 12 Volt 100Ah Battery is not a full battery backup kit by itself, but it can be an important supporting component for compatible setups. Some sump pump backup kits require a separate deep cycle battery, so the battery choice can affect runtime and reliability.
Best for: Buyers who need a compatible battery for a backup sump pump kit or inverter-style system.
Main advantage: It provides stored energy for compatible sump pump backup equipment.
Main limitation: It does not pump water, switch power, or control the system on its own. It must be paired with compatible backup equipment.
What to Look For
- Check whether it is a full kit or only one component. Some products include more of the system than others, while some require a separate battery or installation parts.
- Decide between backup pumping and backup power. A backup pump adds a second pump, while an inverter system powers a compatible existing pump.
- Confirm battery requirements. Not every backup kit includes a battery, and not every deep cycle battery fits every system.
- Check sump pit space. A second pump, float switch, battery box, and discharge setup all need enough room.
- Match the kit to water volume. Homes with heavy water inflow need stronger backup planning than homes with occasional seepage.
- Plan for testing and maintenance. Backup systems should be tested before storms, not only after the power goes out.
Final Recommendation
The best overall battery backup kit for a sump pump on this page is The Basement Watchdog Big Combo CONNECT Preassembled Primary & Battery Backup Sump Pump System. It is the strongest fit if you want a more complete primary-and-backup sump pump setup.
The WAYNE ESP25 / ESP25N Battery Backup Sump Pump is the better choice if your existing primary sump pump is still working and you mainly want to add a dedicated backup pump.
The Pump Sentry 822PS Sump Pump Backup System is best if you want an inverter-style backup kit for a compatible existing AC sump pump. The Renogy Deep Cycle AGM 12 Volt 100Ah Battery is useful as a supporting battery, but it should not be treated as a complete sump pump backup kit by itself.