What is a Battery Backup?

Malcolm Tatum

Also known as an uninterruptible power supply or UPS, a battery backup is a means of providing a continual supply of power to electronic equipment, even when the main source of power fails for some reason. The battery backup is only one of several solutions that are used to keep systems operating even when a utility or other power sources is rendered inoperative for a period of time. Business often include this type of backup along with other solutions as a means of keeping computers and other necessary systems running even in the event of a blackout or some a natural disaster that cuts off the main power supply for anything from a few minutes to several days.

Businesses may be equipped with a battery backup to keep electricity going in the event of a natural disaster.
Businesses may be equipped with a battery backup to keep electricity going in the event of a natural disaster.

Like all types of emergency power, a battery backup makes it possible to switch to an alternative source of power as soon as the main power source fails. Today, it is not unusual for a UPS to be connected to banks of computer workstations, servers, and even telecommunication equipment. When the flow of electricity is interrupted, the backup battery automatically activates, routes power through a surge protector of some type, and allows the connected devices to continue functioning. Often, this occurs with little to no downtime at all.

Most battery backup devices have a limited amount of battery power held in reserve. Earlier designs normally allowed the batteries to supply power for anywhere from five to fifteen minutes before exhausting the supply. This makes them ideal for maintaining operations while a second source of alternative power is put into place and activated. For example, one or more UPS devices may serve as the first phase of the emergency power strategy, and supply power for the ten minutes it takes authorized personnel to connect and activate power generators that are capable of supplying power for several hours.

While the idea of battery backup was once associated more with business settings, the use of this type of device in the home has become more common. UPS devices for home use are usually somewhat compact in size, but just as powerful as many of the larger commercial models of years past. The home battery backup may be used to power essential appliances, keep healthcare equipment up and running, or simply power a desktop computer during a power outage. Over the years, the cost for a reliable battery backup device has decreased significantly, making this type of support equipment affordable for businesses of all sizes, as well as for use around the home.

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I have a lot of information that is on my computer and I try to always make sure my data is backed up. I learned this lesson the hard way several years ago, and have not wanted to take any chances since then.

Having a computer battery backup is also a good thing to have. A little investment in one of these batteries can save you a lot of headaches and frustration if you ever need to use it.

You never know when you are working away and have a power outage. Since you aren't given any warning, all of you work could be lost in an instant.

If you have a computer battery backup you at least have a few minutes to make sure your current open files and work is saved.


Our house is built in a low area, and when we get a lot of rain our sump pumps are working constantly. We don't want to get any water in our basement and if our pumps quit working, we would have a problem.

To ensure that this doesn't happen, we installed sump pump battery backup on our pumps. We have two sump pumps in our basement and it is really important they work right.

It helps to know that if we lose electricity the sump pumps will still continue to work for a period of time. While this is not a long term solution to the problem, it can make a big difference for a little while.


The alarm clock that sits on the nightstand by my bed has a 9 volt Energizer battery backup in it. I know many people use their cell phones for an alarm clock, but I still use a traditional alarm clock to wake up every morning.

Having this battery backup has saved me more than once. I would not buy an alarm clock that didn't have one in it.

It seems like we lose electricity quite often at our house. Many times there is no apparent reason for it. Even though it might not be off for very long, it would be too easy for me to oversleep if my alarm clock didn't go off.

Having the battery backup gives me peace of mind that if the electricity goes off, my alarm clock will still go off in the morning and I won't be late for work.


Has anyone else noticed that whenever you have personal electronics or safety devices that have battery backup, they always seem to run on 9 volt batteries?

I think my smoke detectors have these as a backup, I know my carbon monoxide detector (which plugs into the wall) does, and so does my clock radio so that if the power goes out, I still get woken up.

But those 9 volt batteries sure are a pain to install to those little connectors. (The CO detector was the worst because every time the connector touched the battery, it would emit a loud and high-pitched chirp, and it always took me several tries.) Does anyone know why they're the default?

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