That time a server room meltdown taught me to check UPS batteries yearly

Had a server go down hard at a dental office in Omaha last October. Walked in and the UPS was beeping like crazy but showed full charge on the display. Took a multimeter to the batteries and three of them were sitting at 10 volts each when they should've been 12. Replaced the whole battery bank and the system ran fine. Anyone else check their UPS battery voltage regularly or just wait for the alarm?

2 comments

2 Comments

felix1553d ago

lol yeah that "shows full charge but actually dead" thing is super misleading. They usually measure voltage without a load so a dead battery can still show 12.6 until you actually put some draw on it. I always test mine under load with a cheap battery load tester, not just a multimeter. Caught a couple packs that way before they started beeping. Probably saved me from the same kind of headache you had.

patricia_wells2d ago

That voltage without load thing is sneaky af lol. I actually watched a teardown video where a guy tested a battery that read 12.6v but dropped to 9v the second he put like a 50w bulb on it. @felix155 is right, that load tester is the way to go. I use one too and it found a bad cell in a pack that my multimeter swore was fine.