Best Battery Backup for Existing Sump Pump in 2024

In cases of storms and bad weather conditions, it’s not so uncommon for power to run out. Malfunctions of the sump pump and shortcuts of electricity may leave your basement in complete flood. But what if you can have a backup solution? Finding the best battery backup isn’t easy, but it’s 100% worth it.

Of all the sump pumps that we’ve tested and repaired so far, my vote goes to the Basement Watchdog Emergency Sump Pump. This backup option is easy to set up and it will automatically start up during emergency situations.

Without a proper sump pump, the water damage from your basement can enter your home and cause significant damage!

One of the ways to ensure your pump works even in risky situations is to get the battery backup for existing sump pump.

We’ve made a list of the top 3 battery backups for sump pumps, so you can know what products you can’t go wrong with.

We’ve also included a short buying guide, so you can know what to look for.





Editor’s Pick




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822_PS_Sump_Pump_Backup_System.jpeg Premium Pick Buy on Amazon



Budget Pick




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Best Battery Backup for Existing Sump Pump – Top 3 Products

battery backup sump pump

It can be a challenge to pinpoint into one product and call it the best battery backup for existing sump pump. Different people and properties have different requirements, and there isn’t a unit that is entirely universal.

As such, we have decided to give you not one, but three amazing options that you can choose from.

Here’s what they are:

1. PumpSpy 1500w Sump Pump – Editorial Pick


Key features:

  • Automatically switches from AC to DC.
  • Automatic recharge.
  • 1500-watt output.
  • 1-pound weigh.
  • Aluminum casing.

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This is yet another excellet battery backup that can help you in the case of a power outage. It doesn’t offer as many great features as the Pump Sentry one, but it has a much more affordable price, so you still get great value for the money you pay.

What makes this battery stand out from the rest is that it can power rather large sump pumps. In fact, it can withstand more horsepower than the Pump Sentry, which is pretty amazing. Not just that, but you can use it to power up to two primary pumps! The only requirement is that their combined Amp draw isn’t more than 12.5.

It has a durable aluminum casing that keeps it free from external impact. This also makes it corrosion-resistant and rust-resistant, something that is rather important when you’re combining water and electricity.

In fact, you can use this battery to power many other applications of similar amperage, and not just sump pumps!

Just like the other two pumps we’ve mentioned, it also has automatic recharge, and it will automatically switch from AC to DC once the power is out. This makes it a rather reliable option.


  • Can be used on rather strong pumps.
  • Effortless to install.
  • Protected from external impact.
  • Suitable for many applications and not just sump pumps.


  • Charging is slow.
  • Loud fans.

2. Pump Sentry 822 PS – Premium Pick


Key features:

  • Weighs 17 pounds.
  • Has indicators for battery change, battery replace, and power output.
  • Automatically switches between powers.
  • AGM type.
  • Aluminum casing.

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This is a great and professional choice if you’d like to provide your sump pump with uninterrupted power. It is designed to fit most 0.5 HP sump pumps currently on the market, so you’ll likely have no problems installing it.

This unit connects the sump pump and the wall socket while providing AC power to it. In case of a power outtake, it will automatically convert from AC to DC, ensuring the pump keeps on working. Once the power is back on, it will automatically switch back to AC, without you having to do anything manually.

When the power is on, the battery won’t interrupt with the power that’s being brought to the pump. Also, it has automatic charging options, so the battery isn’t likely to be out of power. Not just that, but you won’t have to switch the battery on/off, as it’ll do that on its own!

The housing is made out of durable aluminum, so the battery itself is safe from external damage. Not just that, but it will ensure the battery is resistant to rust and corrosion while keeping everything lightweight.

The digital control panel will let you know if anything is wrong. Most notably, it has an indicator for battery charge, battery replacement, and power output. This way, you won’t have to do additional diagnoses. The system also has audible alarm system, so you’ll know if anything is wrong.

Finally, the battery is powerful enough to make sure your sump pump is working in just three seconds after the power has been shut down.



  • Can turn the pump on in just three seconds.
  • Powerful output.
  • Compatible with most pumps.


  • Doesn’t come with a backup sump pump.
  • Rather short duration.


3. The Basement Watchdog BWE – Budget pick


Key features:

  • Pumps 1,000 gph at 10ft
  • Weighs less than 10lbs
  • AGM-type
  • LED control panel
  • Dual control switch

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If you’re looking for the best battery backup for existing sump pump, this might be the best unit for you. It does come with a sump pump, but it can be installed alongside your existing unit to provide better coverage and additional safety.

This is an entirely digitalized unit that comes with a 24/7 monitoring system. One look at the system panel will be enough to let you know what’s the status of the pump. In case of a problem, this can help you troubleshoot it quickly.

Once you have a power outage, the control box will activate the pre-existing pump instantly. Also, thanks to its automatic charging options, it will make sure to charge once the power returns. This way, you don’t have to worry about whether you’ve turned the charging on or not.

In general, this is a battery backup that requires very little maintenance. It is resistant to corrosion – but the water might be able to get inside of it. This is a great option if you simply want a unit that will do its job without too much hassle.

The micro-reed Dual Float Switch is a unique technology designed by the Basement Watchdog. This is another feature that is extremely useful, as it improves the performance.

As for the capacity, the pump that you’ll get with this battery backup can pump 1000 gallons of water per hour within a depth of 10 feet. When the depth is 0 feet, it can pump 2000 gallons.

In general, this is one of those pumps that can give you precisely what you paid for.


  • Very lightweight.
  • Safe from external impact.
  • Automatic charging.
  • Quick to turn on.
  • Easy to install.


  • No remote monitoring.
  • Not protected from water and other liquids.

How did I decide what products are the best?

If you are living in Texas, Pennsylvania, Louisiana or Florida sump pumps are not so strange for you. However, it’s very possible that you don’t have a lot of experience or maybe you have no experience at all with backup systems. [source]

These are the few factors that I considered while picking the best backup sump pump solutions for the product. 


Battery backup for existing sump pumps should be of 12 V AGM type instead of the conventional, deep cycle or lead-acid types. 12 V AGM batteries are more powerful and require less maintenance. All you’ll need to do is to seldom refill the distilled water or acid. [2]

A strong 12 V AGM battery will be able to run a 0.5 HP pump for up to 6 hours of continuous pumping, which should be enough for most situations. Also, these batteries have a terminal that isn’t as corrosive.

In the case you’re looking for an integrated backup, it should have a 3000GPH capacity within the depth of 0-10 feet. Also, the pump itself should have at least 0.5 HP – most batteries won’t have any problems with even somewhat stronger pumps.

Also, you should look for a water-sucking depth of at least 22 feet.

Durable Construction

Most backup systems come with both a battery and a sump pump, but we’re assuming you’re looking for batteries alone. Whatever the case, you should look for a system made with a metal framework casing.

Your best option would be to look for aluminum-made bodies, as they are the most lightweight option out of all other metal casings while remaining anti-corrosive.

Another good option is to look for casings made out of dense polyurethane. The denser the polyurethane, the better. This material will ensure the battery is safe from external damage, while also keeping the water out of the system.

Electrical Features

Whether your backup system comes with a pump or not, one thing that must be present is the automatic activation system. Otherwise, the pump won’t turn on when needed unless you’re present.

Also, there should be a digital control panel that will show all the system readings. This way, you can check the system without hassle and keep track of it. If something bad happens, you’ll be able to see it the moment it occurs.

Next, your battery should be able to switch between AC and DC automatically. This will help initiate the pumping system immediately, without any losses. Otherwise, the time of transformation from AC to DC might be long unless you start the system manually, which won’t always be possible.

If your system has an integrated pump, you might look for the best backup sump pump with Wi-Fi. This will help you keep track of the pump’s functionality even when you’re away from home.

Quick and Safe Installation Process

If the backup battery isn’t easy to install, this increases the chances of human error which could lead to malfunctioning. As such, you need to pay attention to how convenient and safe a battery is to install. This can be especially important if it comes with a pump – but, once again, this likely isn’t why you’re here.

To make the installation process easier, the best battery backup for existing sump pump should be rather compact and versatile. Your best option would be to look for a unit that is both surface and wall mountable. This can be achieved with a dual float switch.

If you wonder “What size battery backup do I need for sump pump”, it would be a good idea to keep the system lighter than 40 pounds. This will allow quick maneuverability, and it will be easier to place in the desired location.


Finally, it’s important to state that price is also a determining factor. Even if we find the best battery backup for existing sump pump, it’s worth nothing for us if we cannot afford to buy it.

Not just that, but there are many products out there that are not worth the high price they have. On the other hand, too affordable options are usually made out of cheap materials, and they won’t last long.

As such, your best option is to try to determine which products have the best value for the price.

Is a Battery Backup Sump Pump Worth It?

Whether or not a battery backup sump pump is worth it, and whether or not you should get a battery backup, depends on your situation and preferences. There is not a one-size-fits-all that will work for everyone, and there isn’t a guarantee that a product that works great for someone else will work for you. The same goes for battery backups for sump pumps.

In general, emergency battery backups are worth it for people in rural areas or that live on the city outskirts. In fact, they are pretty much mandatory for people located in areas prone to natural disasters where power cuts often happen.

To determine whether you need a battery backup, try imagining this situation: A heavy rain happens, causing power outtakes. Is this something that is likely to happen in your area? If your answer is affirmative, then you certainly need a battery backup.

Related: Best Generator for Sump Pump 

The Final Word

If you already have a sump pump, you probably think there is nothing else you can do and that you are doomed in case of a power outtake. Fortunately, this isn’t true. You can always get a battery backup that can be integrated into an existing system.

Finding the best battery backup for existing sump pump is something necessary if you often end up without power and live in rainy areas. These units can help you save your property and increase your own safety.

However, choosing among many products in a saturated market can be a huge issue, especially if you are limited by some factors such as low budget or a unique type of pump. You might have spoken to your neighbor who has such a battery backup, but this is hardly a reliable source of information. And your plumber might be biased about the product they are advertising!

While there are many other good options out there, we are certain that you can go no wrong with any of the pumps we’ve listed here. All three units are great in their own way, and all of them have good features that will work for most homes.

Of course, we invite you to do your own research using the buyer’s guide we’ve listed. Hopefully, the best battery backup for you is right around the corner.

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