UPS reboots 1-2 minutes after power is restored

[BillP]

Hi!

I have recently bought the APC Back-UPS ES 700 and connected it to my PC (Win XP Pro SP2, Modecom ATX-300GT 300W power supply with passive PFC), installing Power-Chute 2.0. Then I set up the UPS software to hibernate my windows 1 minute after the the power is off. And it works fine - when I unplug UPS from the wall socket, my system is being hibernated after 1 minute.

Then I plug UPS again to the wall socket restoring the power, but UPS still works from the battery after that (beeps) for the next 1-2 minutes. During these 1-2 minutes I wake up my Windows from hibernation and suddenly UPS shuts everything down (while switching from battery to online), so that I loose everything restored from hibernation!

It works in the same way, when I plug into the UPS power socket my LCD screen ONLY or even when NOTHING is plugged there (all 8 sockets free, only the USB data cable connected to PC). After restoring power (plugging UPS into the wall socket), it still works from battery for 1-2 minutes (beeping) and then sudden power off /power on takes place and after that it starts working online (from the wall socket).

The same thing occurs with another UPS (same model) sent me by APC.

Any ideas about this?

Mariusz
mariusz[AT-DELETE-IT]bozym.com

[Anonymous user]

Here is a brief explaination of your UPS's graceful shutdown process, and what I think might be happening in your configuration.


When a graceful shutdown is initiated, the UPS sends the shutdown signal to any attached computer, and starts a shutdown timer. The UPSs uses the timer to be sure that any connected computer has had enough time bring itself to a 'safe to power off' state, the UPS will shut itself down, and wait for input power to return (this is called sleep mode). Upon the return of input power, the UPS will wake up, and start ouputting power to any attached load.

The UPS behaves this to allow a connected computer to automatically boot up upon power returning after an extended unatended shutdown. Since most computers can be configured (through the BIOS) to automatically turn on and boot when power is applied, the reapplication of power from the UPS after a shutdown should cause the computer to boot up on its own.

It sounds like you might be rebooting your computer manually before the UPS has completed the shutdown process. When the UPS finally does complete the process, it assumes the computer has been shut down it goes to sleep, and cuts all output. I would suggest trying your test again, but do not turn your computer back on manually. If your computer's BIOS are configured to make the computer turn on when power is resupplied, it should boot up on its own, after the UPS comes out of its sleep state.

[BillP]

Thank you dirtfoot for your explanation - I haven't realized UPSes work this way.

Currently I am testing 2 brand-new UPSes (both APC Back-UPS ES 700) with 2 different PC stations.
Station #1 BIOS setting: Restore on AC/Power Loss = Last State.
Station #2 BIOS setting: Restore on AC/Power Loss = Power On (since there's no "last state" setting in bios).

Attached to the wall power socket directly (no UPS), both PC stations start booting, when the power is restored.
Attached via UPS, none of the PC stations boots, when the power is restored to the UPS, even despite of the fact,
that I can hear UPS switching from battery to "online" and cutting off the power for a second. During these tests
I don't try to power on my computers manually. Both PC stations remain hibernated and switched off 20-30 minutes
after UPS switching to "online" (power restored).

[BillP · Accepted solution]

Well, after some tests (using voltage meter) and a short research over the Internet I found out that after a hibernation & graceful shutdown of my PC, UPS still needs some additional 1-2 minutes to go into the "sleep mode" (cutting off the power completely). Restoring the power in the wall when the UPS is in a "sleep mode" results in a correct powering on my PC!

Actually the only problem are these "2 minutes" after hibernating & switching off my PC, which UPS needs to go into the "sleep mode". Restoring the power during these "2 minutes" makes it impossible for the UPS to turn on the PC by cutting off & turning on again the power in its sockets.

What's even more - it works only with "Restore on AC/Power Loss" BIOS option set to "Power On" (doesn't work with "Last State").