Last Updated on May 22, 2022 by Dave Farquhar
My UPS started squawking one Friday evening, the tell-tale sign that the battery was dead or dying. When that happens, it’s time to either replace the UPS battery, or replace the entire UPS. Hopefully you can just replace the battery. Here’s how to replace your UPS battery.
Can you replace your UPS battery?
On some really inexpensive UPS units, the battery isn’t replaceable. Usually you see this on units that cost less than $50. One common offender is the APC BN450M, which consumer electronics stores like to put on sale on holiday weekends. Its $42 or $45 price makes it tempting, but it’s a throwaway unit.
If there’s a sliding door on the unit with a battery inside it, you can, indeed, replace the battery.
Why not just get a new one?
A throwaway UPS costs less than $50. A good UPS costs around $60, and sometimes goes on sale for $50. A battery for a good UPS costs around $35. In the long run, it’s cheaper to buy a good UPS and swap the batteries every 3-5 years as needed. The more expensive UPS also has longer run times, and probably also has a USB port so it can plug into your computer and shut the computer down properly and gracefully if the power goes out and the UPS is about to run out of battery life.
How to source and replace your UPS battery
To replace your UPS battery, you need rubber gloves and a new battery. If you don’t have the manual that came with your UPS, a Google search on your UPS model number will usually turn up compatible batteries.
I sourced my battery locally. It’s better that way. UPS batteries go bad after about a year on the shelf, so you want to buy from someplace that turns over inventory relatively fast. When you find a bad review online about a UPS battery, the most likely culprit is the battery sat too long on the shelf before going into service. A good battery has both terminals labeled so you know which one takes the red wire and which takes the black wire. Ideally it has a date of manufacture on it too. Mine didn’t, unfortunately.
I bought mine at Micro Center, but if you don’t have a well-stocked computer store near you, stores like Batteries Plus frequently have suitable batteries.
Removing the old UPS battery
Some UPS models let you switch the battery while running. I prefer not to do that. I shut down the computer and unplugged everything so I could work in a comfortable, open area. You make fewer mistakes that way. I also recommend you put a label on the new battery so you can keep them straight.
Replacing the battery only takes a few minutes, even if you’ve never done it before.
The rubber gloves are really optional, but if you don’t trust yourself to not touch the metal terminals, wear the gloves. Once you have your battery, pop off the cover and lift out the old battery. I had to flip my UPS back over to get gravity’s assistance in removing my battery from my APC BE550G.
Replace your UPS battery
The wires tend to be short, so don’t expect the battery to come out all the way. Remove one wire from one battery terminal, then remove one of the plastic insulators from the new battery and cover that terminal. Then remove the other wire.
My battery had a plastic lead on the positive (red) terminal. I pulled that off and put it on the new battery. The battery functions fine without it, but it’s extra protection against a short circuit if something goes wrong. There’s no harm in keeping it.
Orient the new battery the way the old one was, then replace the wires one at a time. Push the new battery back into place and replace the cover. Plug the UPS in and power it on. You’ll see the power LED run through a test sequence. If it doesn’t beep at you, the battery is good.
If it does beep at you, make sure you didn’t reverse the wires, and make sure you actually put the new battery in. Hey, it’s an honest mistake.
Recycling the old battery
UPS batteries contain lead and sulfuric acid, so dispose of them properly. Lead and sulfuric acid have no place in landfills, and a recycler can make new batteries out of material salvaged from old ones. Over 90 percent of the material in a lead acid battery is recyclable, so it’s a shame to waste that hazardous material when we can make something useful out of it again.
Stores like Best Buy and Home Depot have drop-offs in the front of the store for recycling consumer batteries. You can leave your old UPS battery at the drop-off for free.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.