Back-UPS Abruptly Shutting Down With Plenty Of Battery Time Remaining

[Anonymous user]

Hello -

I have a Back-UPS BX1500LCD (http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=BX1500LCD&tab=models) supporting a number of devices in my home network core.

Yesterday, I replaced the batteries and installed PowerChute 3.0.0.4 on an always-on Windows XP computer. I also connected the USB cable between the UPS and workstation. With everything operating, the UPS reports a load of 285 watts with roughly 15 minutes of battery runtime.

PowerChute is set to shutdown my workstation after 1 minute on battery. Here's what happens when I pull the UPS power plug (to simulate a power outage):

1. After 1 minute, PowerChute executes a hibernation command.
2. The workstation shuts down.
3. The available battery time rises to about 50 minutes.
4. About 45 seconds after the shutdown, the workstation powers on and begins to boot.
5. The availabile battery time drops to roughly 11 minutes.
6. About halfway through the workstation boot cycle (11 minutes still showing on UPS), the UPS abruptly shuts off. The two red buttons (power and display) remain illuminated for about 20 seconds and go dark. At this point all equipment is off.
7. Still without power, I turn on the UPS and all equipment except the workstation powers up. The UPS shows 50 mins of battery remaining. The workstation doesn't power up on its own this time.
8. Still on UPS, I power the workstation and it fully boots. The UPS battery time drops to 11 minutes.

Can someone tell me why this happens? I can reproduce the behavior every time I pull the UPS power cord. The UPS passes its self test. There are no errors on the workstation or UPS.

Thanks in advance.

[BillP]

Hi Jeff,

I think this is what is happening on your case:

PowerChute Personal Edition default shutdown time line:
1. UPS goes to battery and PCPE starts its preserve battery power counter.

2. When the counter expires it sends a command to the UPS to start counting its turn off delay and then commands the OS to shutdown.

3. The operating system shuts down and the UPS continues to count its turn off delay. (Once the UPS finishes counting its turn off delay it will reboot and nothing can stop this from happening.)

4. The UPS cuts power to the outlets then rechecks to see if the incoming power is acceptable. If it is not it waits there until power returns.

5. If the UPS went to battery due to a brown out the unit at this point will be in low voltage sleep mode until the voltage becomes acceptable again.

[Anonymous user]

JonPro -- thanks for your response.

Here's my issue with all of this... A UPS is supposed to protect the load and maintain power until battery depletion. In the commercial world, a facility UPS comes online at loss of primary power followed by the facility generator (if present). When main power restores, the generator transfers the load causing the facility UPS to go online until main power stabilizes. By design, the UPS/Generator verifies main power frequency/voltage/stability/phase presence/etc. before transferring.

The same expectation applies to my home UPS. The APC appears to work on the front side of an outage, but fails miserably on the back side. Pulling the input power plug simulates a Duke Power outage. Within one minute my workstation shuts down as configured. I plug the UPS into the outlet -- simulating main power restoration. The UPS remains online (doesn't transfer) and then shuts off for a few seconds (causing everything to power off) then transfers to main power. There is no way it could possibly be designed to do this. I have several network storage arrays on it along with my VOIP system and a few other devices. The abrupt outage can cause irreparable damage to my data core.

I respect your theory; if it occurs as written, what's the point of having the UPS if it dumps the load during main power recovery? Totally useless......

How do I resolve the issue...replace the UPS, change settings, etc.?

Thanks again.

[voidstar_apc]

>
I respect your theory; if it occurs as written, what's the point of having the UPS if it dumps the load during main power recovery? Totally useless......
>

The idea is as soon as the computer is commanded to do a safe shutdown, the UPS must shut down even if power returns, otherwise the computer won't turn back on by itself. So to do this, the UPS waits until the load should have safely shut down. Then, regardless of whether mains has recovered, turns off the output. From this point, the UPS will turn back on when mains has recovered and the battery has charged to a minimum capacity (ideally, enough to allow another safe shutdown).

Even our facility UPSes can do this.

If I understand your issue correctly, the problem is your network RAID array isn't safely shut down. Consider: even if the UPS didn't turn off the output upon power restoration, your RAID array would still be hosed should the power outage last long enough to deplete the UPS battery.

>
How do I resolve the issue...replace the UPS, change settings, etc.?
>

Simple options:
- If you unplug the data cable, the UPS won't turn off on power restoration. You also won't get safe shutdown
- Many RAID arrays have the ability to safely shut down when connected to a UPS. However you only have one data cable which you're using for the computer, so you may need a separate UPS for the RAID array. If the array is a low power ARM-based device, this could be a cheap BackUPS.
- If the RAID array doesn't have safe shutdown capability, you could put it on a separate UPS and hope it safepoints after inactivity from the computer.
- If the RAID array has a way of safepointing when the computer is inactive, you could try looking for an option to increase the shutdown time. I know PowerChute Network Shutdown can do this, but I'm not familiar enough with PowerChute Business or Personal editions to provide much help there.

Other options:
- A SmartUPS (SMT or SMX model) can turn off the outlet group powering your computer while leaving other outlets powered.
- A SmartUPS with a Network Management Card (NMC) can safely shut down multiple devices. Of course, the RAID array needs to support the NMC's network signaling.

Maybe someone else here has other options.

[Anonymous user]

To clarify a few points:

1. I added the cable for the expressed purpose of shutting down my workstation before full battery discharge.
2. My RAID arrays are stand alone NAS devices and are not connected to the workstation.
3. The worksation has a RAID 5 array in it along with two attached multi-terabyte USB drives. This is what I'm trying to protect. Before the cable, a power outage trashed the RAID 5 array.

Perhaps there is a firmware update to fix this issue?

[voidstar_apc · Accepted solution]

>
To clarify a few points:

1. I added the cable for the expressed purpose of shutting down my workstation before full battery discharge.
2. My RAID arrays are stand alone NAS devices and are not connected to the workstation.
3. The worksation has a RAID 5 array in it along with two attached multi-terabyte USB drives. This is what I'm trying to protect. Before the cable, a power outage trashed the RAID 5 array.
>

Jeff,

You said that during a pull-the-plug test, your computer shut down safely. That means your goal of protecting the internal RAID 5 arrays is accomplished (and rules out removing the data cable). However your concern now is that your external NAS devices lose power without being safely shut down and are therefore vulnerable to data loss.

While you've stated that your ideal solution is for the UPS not to turn off the output if power returns (and that's definitely possible... apcupsd can do it by disabling "killpower"), there's still an issue if the UPS needs to turn off the output because it ran out of battery power. That's why I suggest investigating how to safely shut down the NAS devices. For example, if you look at [QNAS's Turbo NAS Manual|http://www.qnap-tr.com/File/NAS_Kullanim_Kilavuzu.pdf], there's a section on UPS settings.

edit: Also, you mention in your first message that the computer did not turn back on when the UPS output turned back on. You can probably fix this by adjusting your BIOS settings to turn on after a power failure.