What is a sump pump battery backup?

To answer this question, we need to make an important distinction.

There are many products and systems being sold on the market today called battery backup sump pumps. These are add-on, DC battery-operated pumps that work in conjunction with your primary pump. They serve as a backup in case the primary pump becomes inoperable because of mechanical or electrical failure.

sump pump battery backup

Sump pump battery backups are power converter/control systems designed for wall mounting and used in tandem with a battery or battery bank. This type of system is not intended to replace the function of the main pump in case of failure, but allows the main pump to seamlessly continue functioning at full capacity in the event of a power failure.

A battery backup system for your sump pump is extremely important for providing peace of mind that your home will be protected from water damage. The ruggedness and durability of today’s sump pumps paired with regular inspection and maintenance can make mechanical failure or physical breakdowns quite unlikely. In fact, your sump pump system should last about ten years with the proper maintenance. The more common culprit for sump pump failure is power outage. Battery backup systems can be depended on to operate your pump even when utility power isn’t available, such as losing power during a thunderstorm.

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What are some of the differences?

To help understand the distinction between your two options — a battery-operated auxiliary pump and a battery backup for your existing pump— take a look at this comparison:

dc powered auxiliary pump vs ac powered sump pump battery backup

Busting common myths about sump pump battery backup systems

Sump pumps have been vastly improved over the years, and that has led to their increased reliability enhancing overall dependability when used in tandem with battery backup systems. With such an important topic as protecting your basement from water damage, you need all the facts before making a decision about what kind of system to use. Here are some common myths about sump pump battery backup systems and the truth behind them.


“Two pumps are safer than one.”


Many people install two or more sump pumps in their basement in the hope that if the first one fails—or if the basement floods so much that one isn’t enough—additional pump(s) will act as a safeguard. These auxiliary pumps can be presented in one of two types of packages. One option is a kit that contains a battery in a case combined with a control box and a secondary DC-powered pump. Another option is a second electrical pump, similar or identical to the primary pump. The idea is that the secondary pump can supplement the primary pump in case of exceptionally high water levels.

The truth about the first option (the multi-component unitized system) is that the primary cause of sump pump failure is not mechanical—it’s electrical. Power outages account for most sump pump failures, meaning that only a battery-powered device will still be able to function for their duration. So instead of complimenting the primary pump, the secondary pump ends up doing all of the work.

Why is this a problem? Because typically the DC secondary pump only has about one quarter of the pumping capacity of a 1/3 horsepower main pump. If you’re in a low-lying area where maximum capacity is necessary to keep pace with your water evacuation needs, you’re going to be in trouble if the power goes out and your system is reduced to one small DC pump.

Regarding the second option, because most sump pump failures are a result of power failures, having two electrical pumps is also not an effective backup. You do receive a certain degree of redundancy in pumping capacity in case of extremely high water levels, but if this high water level occurs at a time of power failure, both of your sump pumps will be useless.


“My system will last longer before requiring replacement.”


It may feel as though you’ve beefed up security and increased the life of the system by complementing your main pump with a backup sump pump. But the truth is that your system will last the same amount of time as before, only now you’re going to have to replace two pumps instead of just one. Submersible sump pumps sit in water, and water is corrosive over time. Your two pumps will eventually corrode, and after ten years when it’s time for replacement, you’ll be buying two new pumps instead of one.


“Backup systems that use gel batteries are safer for my family.”


There are those who make the claim that “maintenance free” gel batteries are safer to use. Their reasoning? First, gel batteries are sealed. This means that if they are somehow upended, there is no danger of leaking. This is indeed true. Second, in the recharging process, non-gel batteries may emit hydrogen, which may be viewed as explosive. Although they do emit very small amounts of hydrogen, this gas is very quickly diluted by the air to the point that it has no effect. The conclusive truth of the battery industry is that the above physical advantages of gel batteries are dwarfed by the performance superiority, longevity and affordability of conventional deep cycle (marine) wet cell batteries. For a given capacity (A-hr rating) gel batteries can cost three to five times as much as wet cell batteries. For a given electrical capacity, gel batteries are heavier and offer no performance advantages whatsoever. In summary, the benefits of maintenance-free gel batteries don’t outweigh the performance advantages of wet cell batteries.

When it comes to batteries, sump pump battery backup requires ones with suitable qualities. They must be capable of deep discharge over a long period of time as opposed to providing large quick bursts of energy over very short times like in car engine starting. Wet cell marine batteries are actually the appropriate choice for sump pump battery backup because they are specifically designed for deep discharge. Wet cell batteries are able also to discharge and re-charge more efficiently than gel cell batteries. While this type of battery may not be “maintenance free,” it should not be a disadvantage because maintenance could take place during routine inspections of your sump pump system. Your sump pump battery backup system should not to be taken for granted. No matter which type of system you have, periodic testing of the entire system is a best practice that can ensure your system is in peak condition when you need it most.


“Battery backup sump pump systems are easy to repair and replace.”


Accessing the pumps in your sump pit is often easier said than done. If a component in your system needs to be repaired or replaced, doing so is much more challenging than simply replacing a battery. You will most likely need to call in a professional and pay for parts and labor.


“Multiple-pump kits that include a DC pump are a good value.”


These days, sump pump kits that include battery backup pumps are priced to sell. But in order to meet the target selling price, the quality of the individual system components may not be of the highest standards. Instead of spending money on a lower quality sump pump kit, it is recommended that you invest in one high quality sump pump to be used in conjunction with a battery backup. Not only will you be reducing the likelihood of mechanical failure by having only one pump to repair or replace, but you’ll be ensuring that, in the event of a power outage, your primary, high-capacity sump pump will continue functioning as usual.

The 822PS and 1622PS battery backups are available from our website or
click here to view a list of Pump Sentry Distributors.

If you have any questions or would like to know more, please contact us.