[lini]

The explanation of the failure was very strange to me. I know there are three main UPS types - offline, line interactive, and online. Offline types have the battery disconnected until there is a power outage and only use it when needed. Line interactive and online use the battery more often to absorb power spikes, brownouts, and other anomalies. These two types also use the battery more and need replacements more often than offline UPS.

I have been using the same offline UPS and battery for the last 7 years and it is still working fine - a few days ago it handled a 15 min power outage with 50% of the battery.

Can someone explain why offline UPS can fail if the battery dies? Is it by design or a manufacturer specific issue (e.g. only APC brand ones do this)?

[croutonwagon]

Theres a few more types than that. But thats the gist of it.

"online" is generally a double conversion UPS.

These are generally the best for clean power to the electronics. Since its always supplied by the battery. Its also often one of the hardest on the battery.

Line-interactive are probably most common. They are pretty solid, but since there is a delay for the cutover, surges and really dirty spikes can make it through to the equipment. So say a lightning strike or REALLY bad surge on an overloaded generator can get through, whereas on a Double conversion it may just trip the fuse or breaker. Also running a whole home or standby generator on these line interactive can make them trip constantly since the generators often dont

A) run at 60Hz (ie: mine runs closer to 63Hz)

B) run with a pure sine wave

You can get inverter generators to help with this. But thats a cost too. And otherwise the solution is to "de-tune" the UPS sensitivity.

I de-tune this on mine. Its been fine, running on gennys during the rainy months for hours and every know and then...days at a time.

I have had to swap out power supplies more often..But even then, usually thats after like...5+ years of runtime.

[doctorhandshake]

I was just pricing a UPS for home office use this week as we have frequent outages where I am but became a little stuck when I realized that to get a UPS that won't barf when my generators come online moments after an outage, I'd need a double-conversion UPS, which is $$$$. A little stuck for a reasonable home office option given this wrinkle.

[croutonwagon]

I mean. Im using line interactive ones and have for 4-5 years.

I have to de-tune their sensitivity but they work.

But it does stress the CPU power supply caps a little more and shorten their life. But the caps on the board are fine, and havent had an equipment failure outside of a PSU...And ive run literal weeks on genny power.

But that stress is more due to Hz being at the threshold and artificial stepped sine wave i think. Voltage fluctuations when load kicks up certainly doesnt help.

[kop316]

Re-reading I was thinking the same thing. Batteries don't just "die", they degrade in performance.

How did he also know power didn't go out too? That confused me as well.

[danilocesar]

because he gets emails from the unit when it happens.

I had a script in a raspberry pooling my UPS each minute asking if the unit was running on AC or battery, and dropping that info into a file when it changed. I know the software/daemon can also do something like that.

[jaywalk]

Yes, but in this case he wouldn't have gotten an email since the UPS failed right when the power went out.

I actually had the exact same thing happen to me a few months ago. A power flicker so brief that it didn't even reset any of my clocks, but it caused one of my cheapo standby UPSes to give out.

[monoideism]

Probably he knew because none of his other electrical appliances were reset.