Battery Backup For Existing Sump Pump: System Options & Guide

One of the most common questions among homeowners regarding their sump pumps is if they can add a battery backup to an existing sump pump?

Their curiosities should come as no surprise, as homeowners are constantly in search of better alternatives to the stresses associated with battery-operated backup sump pump kits, which need the installation and setup of a whole secondary pump unit.

Sump Pump Battery Backup System

These backup sump pump kits are often accompanied by six independent parts, which cannot be installed unless you buy some extras, including check valves, PVC pipes, and cement.

Thankfully, you can also include a battery backup to your current sump pump unit. The best part is, the battery backup is extremely easy to Install.

That being said, I suggest you keep reading if you want to learn the usefulness of battery backup for existing sump pumps and how to install them.

Is A Battery Backup Sump Pump Worth It?

The straightforward answer to this question is yes. Even though you rarely face power outages, you can never tell when a heavy storm will strike and cut off the power.

In such an event, your battery backup sump pump will come to the rescue and help prevent your basement from flooding.

How To Install  Sump Pump Backup Power

There are three simple steps to take when installing battery backups for existing sump pumps.

But being easy doesn’t mean throwing caution to the wind, as you still have to study the instructions in the user manual and adhere to them for your safety.

Here’s what you need to do.

Step one: Affix the unit on the wall

Some battery backups are designed to be mounted on the wall, saving some floor space in the process. And I advise you to go for these types for easier installation.

You can also mount the battery backup at a distance away from the pit from an AC wall outlet. As long as the AC cord is long enough to reach the outlet, then this is very doable.

It is also worth mentioning that using other battery cables which didn’t come with the kit can harm the unit’s performance.

To make sure safety is maintained while in use, you should close the battery in a battery box made from durable nylon or plastic.

Now mount the unit on the wall and move to the next step.

Step two: Make the connections

Once you have successfully mounted the backup to the wall, make sure you do the following –

  • Keep the on/off switch off
  • Connect the red battery cable to the red+ terminal on the battery backup
  • Connect the black battery cable to the black- terminal of the sentry
  • Connect your sump pump into the backups outlet
  • Plug the backup into a 120V AC outlet
  • Turn the on/off switch back on
  • Make the connections

Step three: Test your installation

Once you’ve properly set up the system, the next step to take would be to try out the installation. You should begin with a short cycle, just so you know the unit can function under normal conditions.

Once you are certain that the pump is functioning the right way, you can fake a power failure by unplugging the power cord from the AC outlet.

If you find that the power output LED is still lit after you have yanked out the plug, it means that the unit is putting out power. This means your installation was done correctly.

To be 100% sure that everything is working fine, cycle the pump one more time while in the battery backup mode.

Once you have finished your testing, you can plug the power cord back into the AC outlet. Wait for about two seconds, and you should notice the LED indicator flashing.

This signifies that the unit has been reconnected to an AC power source.

You can cycle the pump again as a final test.

How Long Does A Sump Pump Battery Last?

One of the most important factors to consider when buying a battery backup is the sump pump backup battery life, and how long it would be able to run in the event of a heavy rainstorm.

This is a vital consideration because many homeowners have been faced with the disappointment of basement flooding, as a result of their battery backup failing in the middle of the storm.

That being said, it would be wise to inquire how long a battery backup would last, as it will help you prepare for such rainy days.

Knowing the lasting ability of your backup battery can also prompt you to invest in other alternatives like a water-powered backup sump pump.

Keep in mind that as far as basement flooding and power outages are concerned, your backups act as a last line of defense when your pump falters.

As for how long the battery will last, it should go for about 7 hours on a full charge while pumping continuously, and about 3 days of non-continuous pumping.

As you may have already guessed, the longer the pump is in use, the more power is consumed and the less power it has. If this continues, the battery will reach a point of the total drain, and it is at this point the unit will shut off.

If this ever happens, the sump pump will no longer be able to remove water from the sump pit, it will overflow, and your basement will become flooded.

I have to mention that different batteries have different power capacities, which means some backups will outlast some others. Simply put, the higher the Ampere Hour (Ah) rating, the longer it can run during the time of a heavy storm.

On average, a 40 AH battery can last about 4 hours, so it might be ideal for you if the rainstorms in your area don’t last that long. However, if you usually experience longer showers, then you should buy one with a higher capacity.

It is also worth mentioning that the more powerful the pump motor, the faster it will drain the battery power.

Most backup pumps are 1/3HP, which is more powerful than a 1/4HP. This means a 1/4HP pump will draw less current from the battery, allowing it to last longer in the process than a 1/3HP pump.

Keep in mind that even though a 1/3HP pump will drain the battery faster, it will also pump out standing water faster, thanks to its superior power.

With this taken into consideration, it is not uncommon for battery backup makers to recommend more expensive batteries (which are usually more powerful) to be used alongside more powerful sump pumps.

Water-Powered Backup Sump Pump Installation

Since battery backup sump pumps have a limit to how long they last during a power cut, it would be wise to consider another alternative – A water-powered sump pump!

This type of pump functions by using your home’s municipal water pressure, which means you wouldn’t be needing any electricity or batteries. This means that the pump can run for as long as necessary, as it will not run out of power like battery backups.

As you can imagine, such a dependable waterproofing solution wouldn’t come cheap. It costs significantly more than battery backup pumps.

Causes Of Backup Battery Failure

Nothing lasts forever, including your battery backups. And this is due to many factors which I will mention below.

The first of many of these factors are age, so keep it at the back of your mind that a day will come when the backup battery will no longer be able to function at its optimum.

The longer your battery lasts, the weaker it becomes. And while it will still function, there will be an obvious decline in its voltage.

The age of the battery also determines its ability to charge and retain voltage. The older the battery, the less capable it will be in this regard.

This means a brand new backup sump pump battery that could once last for 7 hours may not be able to last for more than 3 hours over the years.

With this in mind, it is recommended that you change your backup battery every few years if you want the best results.

Other causes of backup battery failure include –

  • Corroded lead plates in wet-cell batteries
  • Exposure to extreme heat and cold
  • Too much humidity

Final Words

Sump pumps can be very useful when it comes to basement flood prevention, and that is why they have become a popular feature in many basements.

However, they are just machines, and their batteries can also run out, and this is where backup batteries come in.

Battery backup for existing sump pumps can be your savior in times of heavy storms and power outages. So yes, it is worth the investment.

And while they certainly won’t last forever, they will do the job they were installed to do when they are in their prime.

I hope the information provided here has been helpful.

Thanks for reading!

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