Battery Backup Sump Pump Buying Guide

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If you’ve already installed a sump pump, it can feel awkward to have to do the job all over again to get a battery powered pump, which will kick in if for any reason your main sump pump stops working.

Just like when purchasing your main sump pump, there are new terms to understand and features to get to grips with before you can decide exactly which model is best for your own needs. The process can seem arduous, but with our battery backup sump pump buying guide, we’ve made it as simple as can be.

Why You Need a Battery Backup System

Though your primary system will likely be the best way to clear water in terms of power and efficiency, a battery system is recommended in every situation. Sump pumps require some form of power, and this means that when conditions get bad they can be susceptible to power outages or even damage from water or overuse.

Battery Backup Sump Pump

Unfortunately, these conditions often coincide with times when a sump pump is most needed. For instance, a flood may interfere with your power supply, but it will also lead to a build up of water in your home, so your sump pump is most needed at this time.

Some people opt for water powered backups. These aren’t quite as brilliant as they may sound, as you may assume they are powered by the flooding water itself. Instead, these run off your mains water supply, and they can be expensive to install and run. This is why many people go for the battery backup system, which is a more efficient way to do things in most situations.

Battery Types

The type of battery is another important factor in your decision. Within battery powered sump pumps, the power settings are either DC, or AD/DC. Battery backups will know to use DC power when the AC (power from the wall) is not working, or the primary pump has failed for any reason.

Sump Pump Battery Types

Types of batteries include deep-cycle or ‘maintenance free’ models. These are sealed batteries which, once installed, don’t require you to do any sort of upkeep. They are called this because some of the other options, the  ‘lead-acid’ options, need distilled water to be periodically added. This is why they are sometimes referred to as wet cell. The water is to stop the lead ‘cells’ stopping from working, which can happen if they get too dry.

While there is not necessarily a single ‘best’ type of battery, the deep-cycle, maintenance free batteries are popular for obvious reasons. They don’t require you to check them from time to time or add anything to them, something it can be very hard to remember to do when it comes to sump pumps, which simply sit in our basements most of the time.

Alarm Systems

Batteries, of course, will only cover you for a limited period of time. This is why you don’t want them to be running unless they absolutely have to. If your primary sump pump fails and your backup model has to kick in, you need to know this is happening. For instance, the pump may fail when you have no idea there is any issue, and the battery powered pump will start to do its thing. This will only work for a limited time, and like a car battery when you leave your headlights on, will drain over time.

Sump Pump Alarm Systems

If the battery has drained at a time when you didn’t know it was happening, when the flood comes or the ice melts and the water flows in, both of your pumps will not be working. Of course, this can lead to huge problems and render having a sump pump totally useless. Imagine spending the money on having two separate sump pumps, and still not being able to manage when conditions get difficult.

How Does The Battery System Work?

The sump pump system normally uses a float, which triggers the sump pump to kick in when a certain water level is reached. The backup system works in exactly the same way, however it should be installed higher than the primary pump. This means that if the original pump doesn’t work, the water will continue to rise and then the second pump (your backup battery sump pump) will kick in. The battery power will only be used once this has been triggered.

As you can see, the two sump pumps themselves do not actually communicate. There is no technology which links the two exactly, it is just that the primary pump is set to kick in first, and if it doesn’t, the secondary pump will do so. The fact that the two aren’t linked is actually beneficial. It means any issues affecting your primary pump won’t affect the secondary, backup model.

How Long Do Battery Sump Pumps Last?

This is not the sort of question that can be very simply answered, and it varies from model to model and battery to battery. Fortunately, batteries are of course, replaceable, so as long as the battery will see you through one particular storm or difficult period for water overflowing, you can simply replace it afterwards.

The length of time the sump pump lasts also depends on how hard it is having to work, in many models, it will pump faster and using more power if the water is filling up quickly, which means that the battery will last less time. For instance, some sump pumps may last up to 50 hours when used sparingly, but if they have to work to their maximum capacity, they may use the power in as little as 12 hours. Many battery backup sump pumps will warn you when the battery is running low.


A backup system of some kind is absolutely essential, and having one which utilises batteries can be one of the most cost-effective and simple ways to get a backup up and running. Installing and using it correctly, as well as understanding the mechanism, can ensure that you get the most out of it and ensure it doesn’t desert you when need it most.