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I've never had an uninterruptible power supply and think of buying one. What not-so-obvious things should I not do to the UPS so that it lives longer?

I don't mean some obvious abuse like dropping/exposing to direct heat/exposing to wrong voltage. I mean less obvious things like its not acceptable to leave an acid battery UPS unplugged for long time after it has been used because some chemical processes start in half-discharged batteries and render the batteries unusable. What other misuses should I know about?

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up vote 2 down vote accepted

If you know you have wonky power (flicker flicker) adjust the sensitivity of the UPS so it doesn't trip for every little flicker. My apartment unit is next to the elevator. I killed a set of batteries in 8 months this way.

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The SLA (sealed lead acid) batteries in UPSes shouldn't be left in a discharged state. If they are, sulfates will build up on the plates and their capacity will be reduced. This isn't normally a problem in UPSes, since they're always plugged in and after a power outage will charge the batteries back up when the power comes on. But if you somehow decided to unplug a UPS after the batteries were drained and then left it sitting unplugged for a week, you'd probably notice the battery discharging sooner next time.

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APC suggests that if you stop using a UPS, you should disconnect the batteries - and that said batteries will last a long time. – Mei Oct 31 '11 at 15:46

Dont overload it. If it has a nice status screen to see the load on it try to keep it below about 60%

By discharging it faster will wear out the the battery faster

Heat, humidity are also bad for it.

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While in college I was moving some servers from one room to another. They all where on a really old UPS which apparently had less protection circuitry then current UPS equipment. I started by disconnecting all the servers from the UPS and moving those. Then without shutting down the UPS I unplugged it from the wall. Sparks started shooting out of the UPS and it literally started bouncing.

The electronics teacher had a plausible sounding explanation about why something like this would happen given the design of the UPS, but I don't remember enough details to explain it here.

So the moral of the story is this.

  • When there is no load, always turn off the UPS before disconnecting the power.
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Generally sound advice for all electronic equipment – SpaceManSpiff Jun 22 '09 at 9:08

According to the answers to my question over here, it's a bad idea to have a power strip touch it either upstream or downstream.

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Don't plug a UPS into another UPS (i.e. Daisychaining them).

There's a good discussion on why not to here, or from APC themselves here.

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I have a great story about that .... a 6 UPS dasiychain. We had to turn them off to move equipment. Then no one could figure out which one we needed to turn on first ... That was a great day. – Joseph Kern Jun 22 '09 at 10:34
You're not likely to have one, but I have heard stories of people running a ferroresonant (Sola) transformer through a UPS and literally blowing it up. – dmoisan Jul 6 '09 at 17:12

Your main concern should be heat. Don't cover it with a bunch of stuff. Keep the vents clear, and allow airflow.

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