Battery Backup For Existing Sump Pump: How It Works
When it comes to battery backup pumps, the first thing that comes to mind to many is buying a unit with a primary sump pump and battery backup pump combination. But, did you know that you can add a battery backup to the existing sump pump you have?
You can add a battery as a power source to your current sump pump. Usually, the battery is mounted on a wall and connected to the sump pump. However, you can also get a whole new unit, a new battery backup pump in addition to your existing sump pump.
Installing a battery backup can be quite tricky, don’t worry, a thorough explanation follows next.
Table of Contents
Is it possible to add a battery backup to the existing sump pump?
You have 2 choices for adding a battery backup to your existing sump pump. Adding a battery as a power source or adding a whole new unit.
Benefits of adding a new battery backup sump pump
Adding a new battery backup pump is a much safer option, but as always, it depends on your preference. With a battery as a power source to your existing sump pump, you are not safe if the pump fails.
The battery will cover you in power outage events, but it won’t be of any use if your pump malfunctions. That is why some prefer adding a new battery backup pump to the existing sump pump.
That way, your basement will be safe in power outage events and when the existing sump pump can’t work. In addition, the battery backup may help the existing pump at certain times, when the water level is too high.
Quick overview
 | Adding a new battery backup sump pump | Just adding a battery backup to an existing sump pump |
| Protection against power outages | ||
| Protection against sump pump malfunction | ||
| Extra protection during heavy rainfalls |
It doesn’t matter what kind of a sump pump you have; you can always add a battery backup. It’s important to pay attention to the voltage. If it’s too high, the pump may burn out, and if it’s low, it will not be efficient when needed.
If you add a battery backup as a power source for your pump, you need to make sure that your basement has the right conditions for it. Find a good spot on the wall, away from any water.
However, if you decide to add a new battery backup pump, then you need to make sure you have enough space in your basin. The battery backup is usually installed above the existing pump.
On a side note, buying a battery backup comes with a responsibility. To some batteries, you have to put fluids in them, and you have to replace the battery every 3 years. Those are some additional costs that may occur.
How to install a battery backup?
I am obligated to tell you that if you are not sure that you can install a battery backup by yourself, call a professional. Handy people usually don’t have any problems, but if you are unskilled, hire an electrician.
Adding just a battery backup
If you have decided to add a battery backup as a power source, then you will need some things from the store. Buy a battery, protective case for the battery, an AC/DC interface, a red battery cable, and a black one.
You will need to mount the battery on a wall, close to a power source. Keep in mind that you can’t use extension cords for the charger and the pump. The protective case will have instructions on how to mount it on the wall.
Once you mounted the battery, you will need to connect the battery cables with the interface. Make sure that the ON/OFF button is on OFF. The black one is for the negative charge, the red one for the positive.
The interface serves to charge the battery and convert the AC/DC. Plug your pump in the interface AC supply and plug your interface in an AC supply. A good interface you can buy is the Pump Sentry.
That should be it, test the battery backup to see if you installed it properly. Unplug the interface from the AC supply and see if your sump turns on when there is a power outage event.
Adding a battery backup pump
Now, if you want to add a new battery backup pump, the process is quite different. You are adding a second pump to the basin, it sounds complicated but it’s not, these backup units are easy to install.
Adding a battery backup pump means that you will need more space in the basin, one more pipe to connect to the discharge line, one more check valve, one more float switch. If you had trouble installing the existing sump pump, call a professional for the battery backup.
Battery backup pumps rarely come with a battery in the box. You will need to buy a good, reliable battery. If you will rely on it in emergencies, make sure you get a good one.
Planning the discharge lines
Start by planning how will you connect the discharge lines. A good option is getting a PVC pipe that will have an opening for the backup pipe. The main discharge line should be connected with the main pump.
The backup pipe should be connected with the battery backup pump and then on a 45 degrees angle. In the end, connected with the main pipe with a Y connector. Install check valves below the 45 degrees angle and below the Y connector.
The check valves will make sure that water does not flow back into both sump pumps. If you only get a check valve for the main pipe, water will flow back when battery backup is active.
Installing the battery backup itself
Now, you can start installing the battery backup. Place the backup next to the existing sump pump but make sure that they don’t touch together. Then, you can start connecting the discharge lines.
Install the float switch of the battery backup above the main pump. Choose a water level where you think that the battery backup should turn on. Place the float switch on the discharge line.
You can now connect the battery backup charger. You don’t need an interface for this option, a simple charger will do. No need for converting AC/DC.
Testing the installation
Once done, disconnect the main pump and test the battery backup. Pour buckets of water if needed to reach water level.
You will still need to replace the battery every 3 years and keep proper maintenance. This battery backup option will make sure that your basement is safe even if the main pump fails.
That’s all about how to install the battery backup, let’s recommend some good battery backups.
What battery backups can I buy for my existing sump pump?
As I said, the Pump Sentry is a really good choice if you add a battery as a power source. Reasonably cheap price and reliable unit. The Pump Sentry will keep you safe from electricity dangers and makes sure that the pump starts in power outage events.
Good battery backup pump options are the WAYNE ESP25 and the Zoeller 508-0005 Aquanot (affiliate links to Amazon). Both are very powerful but expensive. These may cost a lot, but not more than repairing your basement.
Both are very efficient, maybe more than your existing sump pump. Both have alarm warning settings that will signal you when the battery backup is working.
Customers are very satisfied with these battery backups. You can find these sometimes in the main pump and battery backup pump combo, but as single items, they are much better.
Lastly, for the most extreme combination of heavy rainfall and power outages, there’s always the Pump Sentry 822 PS, which has countless of homeowners testifying that it saved their basement.. But it does makes the ESP25 and the Aquanot look cheap.
If you decide to go with the Pump Sentry, I strongly recommend that you check whether your existing sump pump is compatible with either the model 822PS or the 1622PS here.
Hope this helped you, good luck with your choice.
Related questions
Is a battery backup worth it?
Of course, it is. Few people complained about having a battery backup and all complaints are about the pump’s quality. You can’t put a price on safety. I don’t think you can afford to be without it.
Do I need a battery backup?
It depends on where you live. If your area is really prone to power outages, you absolutely need one. Maybe you need one to help the main pump during the rainy season. However, there are other backup options that may suit you better.
How long does a sump pump with a battery backup last?
During power outages, your sump pump is completely reliant on the battery backup. How long your sump pump will remain working, depends on the capacity of the battery, as well as the voltage of your backup sump pump. Moreover, an important factor is whether your sump pump will run constantly, or intermittently.
On average, a sump pump running on a backup battery will last for about 4 to 5 hours when running constantly.
If the float switch only triggers the sump pump to run part of the time, your backup could run for a day or so. Most backup systems will sound an alarm when it is activated, giving you plenty of time to deal with the situation. So your sump pump will last anywhere from 4 to 24 hours after the battery backup system is triggered.
