Hacking APC UPS's "Master/Controlled" Feature?

The specs for this discontinued product state that the five outlets across the top are backed up by the battery.

These outlets will run until the battery voltage drops to where it can no longer power the outlets. At that point, those five outlets will all shut off. KA-CHOOM!

IF the device has a "master" outlet (I don't see it in the specs or the photos), the "controlled" outlets turn on and off with the master, either for convenience, or to save energy. (My audio system is wired this way -- the electronic crossovers turn the power amps on and off.) Once the battery poops out, /everything/ powered by the battery shuts off. There is no graceful shutdown.

You're confusing a convenience feature with operation of the device as a source of backup power. The two (apparently) have absolutely nothing to do with each other.

On Sun, 30 Oct 2011 18:50:54 -0400, PeteCresswell) wrote (in article ):

Your understanding of how it should work is the same as the user guide's:

Perhaps you have inadvertently disabled it? Did you try pushing the button as mentioned?

You can download a copy of the user guide from the APC site.

Per Nelson:

The lawyers or some other clever souls added weasel words in the User's Guide | 2 Connect Equipment | Master/Controlled Outlets | "Note: Do not connect peripherals to the Controlled Outlets if you want them to continue to run when your computer is turned off."

For the life of my I can't imagine why they would inflict such a flawed implementation on their customers. I mean... this is an Uninterruptible Power Supply, not a friggin power strip... it's all *about* function when the power fails.

The least they could have done is put that little disclaimer on the outside of the box.

Per (PeteCresswell):

Sorry.... that was a non-sequitur..... I'm so pissed off over this that I'm not even thinking clearly any more.

But, to answer your question, yes - I have the feature enabled.

It's just that it does not work when the user needs it the most: when the power fails.

On Mon, 31 Oct 2011 19:56:46 -0400, PeteCresswell) wrote (in article ):

I don't understand what you want. Do you want the "controlled" outlets to continue to have power after the computer shuts down? There are other outlets that operate independent of the "master" which do that. As I understand it the idea behind the "controlled" outlets is that a peripheral which is only used by the computer, eg a printer, doesn't need power if the computer is down, so to conserve the remaining battery power for the useful items, these are shut down in synchrony with the computer.

I have one of these and it works just fine. There are "uncontrolled" outlets which are supplied with power whether the computer is up or down, "controlled" outlets which are only supplied with power when the computer is up, and surge protected only outlets which are not supplied with backup power. I would have chosen the mix between these differently, but that is easy enough to get around by plugging power strips into one or the other types of outlets.

In my set up, I have the external hard drives and printer connected to the "slave" outlets and the cable modem and VOIP modem connected to the "always up" outlets. When the battery is down to 25%, the computer shuts itself down along with the peripherals and the modem and router continue to provide telephone service. Isn't that the same thing you want?

Per Nelson:

I want the "controlled" outlets to be controlled by the "master" outlet - at all times, as I think most people would impute from what it says on the box the power supply comes in - not just when there is external power.

The reason: if the power goes out, I still want connectivity across the LAN, but I don't want the UPS' battery tb drained (which shortens it's life).

Sequence Of Events:

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- Power fails

- UPS keeps supplying power to PC connected to "Master" and to devices connected to "Controlled"

- UPS sends message to PC telling it that we're on battery backup

- PC keeps on truckin'.... with LAN connectivity still intact

- PC's Power Management utility kicks in and, after a preset time or a preset remaining battery life, commences a graceful shutdown of the PC

- PC shuts down.

- UPS then shuts down the router, switches, and whatever else is plugged into "Controlled" outlets.

- The UPS battery does not get totally drained.

----------------------------------------------------------------

Maybe I'm the only one.... But this seems so obvious that I just can't imagine any other implementation in the context of an Uninterruptible Power Supply.

The power-saving thing sounds nice, but I go back to the fact that this is an Uninterruptible Power Supply, and not just a power strip.

This may sound like nit picking.... but it's not quite true that they are only supplied with power when the computer is up. What's true is that they are only supplied with power when the computer is up *and* there is external power.

Where are they getting power, if not from the UPS?

And would you want your laser printer to keep running from the battery? The design seem sensible to me.

Jerry

On Tue, 1 Nov 2011 10:22:28 -0400, PeteCresswell) wrote (in article ):

You're right. I did some plugging and unplugging and checking. If you look at the top line of outlets they say "Backup Power + Surge" while the bottom line says "Surge Only". The three "Controlled Outlets" are on the bottom so I guess that's intended to make it obvious that they are surge only (although my initial impression was the same as yours).

I guess the thinking is that you wouldn't want to be running printers, scanners, etc. when you are on backup power as that would shorten the amount of time the computer would be able to run. And when you are not on backup power, it is convenient to shut off peripherals automatically when you shut off the computer. But I agree it is confusing to include surge protection only outlets in a UPS.

Another set of outlets which run on backup power but are controlled by the computer would be useful for attached external hard drives, for example. That's how I would use them anyway.

I find it a good little UPS for the money. I bought it to get through short duration outages and it does a good job of it. I don't find the lack of computer controlled, back up power outlets to be that much of an issue, certainly at this price point. Not worth getting upset over anyway :-)

Per Jerry Peters:

No - so I would plug it into one of the uncontrolled outlets.

??

Per (PeteCresswell):

Oops.... "uncontrolled" SHB "surge-only"

Per Nelson:

Agreed - I just have this tendency to go ballistic when I see (according to me.... -) especially-egregious violations of common sense.

The thing about avoiding the router/switches draining the UPS battery seems to me tb totally basic to the power loss situation.

I'd been using one of these guys

Per (PeteCresswell):

Or one of these:

On Wed, 2 Nov 2011 09:51:42 -0400, PeteCresswell) wrote (in article ):

So I'm guessing you are going to plug the Belkin into the Master on the UPS, the computer into the Master on the Belkin, and the things you want to stay up as long as the computer does into the controlled outlets on the Belkin.

You must have really shitty power if you worried about draining the battery. My outages are generally not long enough to cause the computer to shut down much less discharge the battery completely. I doubt if completely discharging the battery once or twice over it's lifetime will have much of an impact.

On a side note, I think obsessing over "standby power" to save the planet is absurd in the greater scheme of things. More of a "feel good" effect than anything meaningful. And some equipment relies on the standby power to maintain its state. For instantce, my external speakers reset their volume to zero whenever they are powered down.

On Wed, 2 Nov 2011 09:27:38 -0400, PeteCresswell) wrote (in article ):

I hear ya :-) Fooling around with my UPS as a result of this thread has reminded me of what a mess all those little transformers are. I have a Mac Mini, 6 external Firewire or USB drives, a scanner, a printer, a router, a cable modem, a wireless access point, an external DVD burner, a cell phone charger, and a telephone. All have different geometry transformers which block at least one adjacent socket. I bought some 6 inch pigtails that were supposed to fix the problem... but the pigtail plugs are so fat that you can't plug _them_ into adjacent sockets. And it must be a rule that the plugs on the transformers are orthogonal to the slots on the power strip outlets so that you end up blocking multiple outlets. Underneath my desk is a rat's nest and a fire hazard.

I have two power strips hanging off the UPS and 6 pigtails just to manage to plug everything in... and the result is well under the UPS' capacity.

Per Nelson:

Our outages are rare (as in 1-2x per year max) but when they happen they can be a day or two. The one we just had was a couple hours short of two days for us, about 4 days for the guys across the street.

Within those outages, of course, are many mini or micro outages where some high-startup-current device kicks in and the lights dim for long enough to trip a UPS. But in those cases my concerns are moot.

I don't know enough about batteries to have an authoritative opinion, but what I've always heard is that total discharge damages lead-acid batteries from the get-go. I'm pretty sure I've cooked a couple of batteries on my automobiles by totally discharging them two or three times. I think that is what's behind the special "Deep Cycle" marine batteries: they're specially made so that deep or total discharge will not harm them as much.

But, to address what I perceive is the real issue: yes, I might be over-thinking this and yes, it's much more theoretical than practical.... but that's just my inner obsessive.... -)