How to Add a Battery Backup for an Existing Sump Pump

How to Add a Battery Backup for an Existing Sump Pump?

Floods during the rainy season are a widespread thing. We know how much hassle the owners have to go through if they find their basement completely filled with water.

A sump pump might be a good idea to think about a solution! Any home with even the least amount of water incursion into the basement or crawlspace on a regular basis should have a sump pump installed.

Now, what if there’s a blackout? Then the power feeding the pump won’t be available, and you might have to swim until the blackout condition is retrieved.

There, you should know how to add a battery backup for an existing sump pump to help you with such additional disasters. Read our article to discover more about it!

What Is There to Know About Electric Sump Pumps?

Sump pump

As we have already mentioned above, electrical sump pumps are the savior of all your flood problems. Whenever there is an overflow of water in your basement, a sump pump can automatically turn on and force the water to drain through the pipes.

The measurement of the water level is taken by the sensors in the sump pump that triggers automatically after the flood reaches a certain level.

These machines are very easy to install and also affordable. Not only that but because of its function, your basement can be free of molds or any other dangerous bacteria.

Now, let’s consider a scenario where a harsh thunderstorm fused the electric cables around your house. Since your pump cannot operate in blackout conditions, living with flood water gradually rising from the basement will be very troublesome.

At that moment, one major precaution to fight the flood is to install a strong battery backup for your sump pump.

Installing a battery backup pump will be a simple technique to make sure your pump keeps running even if the power goes out.

How Does a Battery Backup Sump Pump Compensate for The Blackout?

Let’s assume that you have a 120-volt electric sump pump. All you need to do is to connect a 12-volt backup pump with battery coverage to compensate for a blackout condition.

The battery-powered backup pump will immediately start up if the electricity goes off and the pit is completely filled with water. To ensure a 24-hour service, an electric charger keeps the battery backup pump fully charged and ready to use anytime.

Sump pumps that come with a battery backup are straightforward to install. If you’re thinking about the cost of such installation, it’s rather dependent on the capacity of the pump. But our research suggests that the average cost range falls between 300 to 500 dollars.

The installation time requires 2 to 4 hours, and most house owners can carry out this task all by themselves. Let’s check out how to install it.

How to Add a Battery Backup for an Existing sump pump

  • Add a check valve to prevent water from running back into the sump pit.  You can use Teflon tape to seal the end of the valve.
  • Place the battery in a safe plastic box on a wall-mounted shelf rather than on the ground.
  • You’ll need an electrical outlet port for both the electric sump pump and the battery backup pump. It’ll be wise to hire a professional electrician to create the outlet.
  • It’s vital to release the water onto a downward slope and away from the home while pumping it outside so that it doesn’t flow back into the basement. You can utilize one other way: pump the water through a drainpipe that leads to correct disposal.

Things to Know About Battery Backup for Existing Sump Pump

Up to this point in the article, you might have some questions about the longevity of the battery backup of your installed sump pump. The inverter/battery backup system is completely dependent upon the amount of water it has to displace from your basement.

Let us give you a demonstration! Assume that you have a battery backup system with 40 amp/hour. This rating of the battery is said to last up to 53 hours, keeping your pump functional.

But, if there are circumstances where the backup pump needs to discharge water once in a minute, then the battery backup time will reduce to 12 hours which highly decreases the efficiency.

Therefore, that’s an insufficient battery capacity to get you through a prolonged power outage. In such a situation, get a system with a bigger battery or a charger capable of charging two batteries simultaneously.

Every certain thing has certain advantages and disadvantages, and a battery backup pump isn’t exceptional in this case. So, make sure to note these below bullet points in your mind hardly.


  • Easy to install.
  • Works efficiently in terms of a blackout.
  • Once installed, the lasting period is quite long.


  • It’s possible that the battery will die before the electricity is restored.
  • Every few months, the battery’s water level must be checked.
  • You need to clean the battery terminals every two years maximum.
  • Normally, the lifespan of the battery is about 5 years. It’ll cost you almost 500 dollars to get a new battery for the backup system.

Frequently Asked Questions

Can a battery backup run a sump pump?

The primary sump pump will run on electricity when your home’s power is turned on. In the event of a power outage, the battery backup system will kick in and supply the energy required to run the backup sump pump.

How long will a battery run a sump pump?

Most fresh, fully charged batteries will last around 5-7 hours in case it needs to pump water continuously during the power failure. In a normal scenario, the battery backup will last up to 1-3 days, depending on the usage.

How can I run my sump pump without electricity?

If you live in a location where power outages might last days rather than hours, a home generator may be the best alternative. Until the outage is ended, the generator will be able to power the house, appliances, and sump pump.

What size battery backup do I need for a sump pump?

As we have already mentioned, most electrical sump pumps tend to operate on a 12-volt battery, but we will recommend using a lead-acid battery with a capacity of 75 ampere-hours.


Through a series of simple steps, now you know how to add an Inverter/Battery Backup for an Existing Sump Pump. Remember, it’s also important to purchase a good battery rating for greater service and durability.

If you want to install a battery backup to an existing sump pump, check out the model of SEC America to help you with this task.

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