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UPS Battery Backup -- useless when the battery dies?

by bdsolomon / December 7, 2008 4:28 AM PST

I have a UPS by each of my DVRs as well as elsewhere (my router/Vonage/cordless phone base). I figured that such action would be good -- if power goes out I have backup, while power is on I have surge protection.

I came home after a vacation, and it looks like the battery must've hit the end of its life, in my APC backup. I went inside and heard a siren, and traced it to the backup on the DVR where I had most of my recordings set.

OK, so that means that I have no protection should the power go out, right? Well if you think that, you're as ignorant as I apparently was. It seems that the backed-up outlets go dead when the battery dies. Does that make sense? Those are the outlets I want to be up as much as possible, and they go dead when there was no power event (I know that because the clock on my microwave is so sensitive that it can get zapped when I don't even notice a power dip).

Had I used a simple surge protector, I would not be able to record when the power is out, but when it came back, the clock would be set again and the schedule would be safe. Because I took what I thought were extra precautions, I ended up with the whole thing shut down for most of my vacation.

Disclosures: I suspect that the batteries were more than 2 years old, so they were likely beyond the "guaranteed" life, but there was no earlier warning beeps to suggest that. Also, it is possible that had I hooked it up to a computer, that there would've been an alert about the battery capacity going to zero. But as I said, I have several battery backups not connected to computers, protecting (or so I thought), other critical equipment.

Is this backup a lemon? Are all backups like this? Are all APC backups this useless?


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Why not?
by R. Proffitt Forum moderator / December 7, 2008 5:00 AM PST

Test your APC units every 2 years and put new batteries in when they fail?

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Is this the way all UPS units work?
by bdsolomon / December 7, 2008 6:07 AM PST
In reply to: Why not?

Testing (without hooking up to a PC), involves powering them off and back on, which MAY (I'm not sure), indicate that the battery is low. It also powers off the outlets, which in the case of the TV, requires reprogramming it (maybe not if only for a few seconds).

Every two years is not sufficient... Assuming that the stated life is 2-3 years, you really would need to do it weekly or monthly as you near that point. And repeated tested DOES lower the battery life. With an earlier APC UPS that I used for a computer, I used to shut everything down with the UPS power button. The battery died in less than the minimum 2 years; APC told me that each power cycle did a test, tests drew down the battery, and detracted from the life.

Come to think of it, I seem to recall that they did weekly testing automatically... shouldn't they give some audible warning? Or maybe it was one of those weekly tests that determined that the battery was too weak to sustain a load, so they did me the favor of dying.

I realize that I'd be unhappy if the unit started a constant alarm when the battery was detected low but still usable, but at least that would allow me time to take some action. Unless I basically plan to replace all the units every two years (or maybe buy new batteries), this kind of action makes a UPS less secure than a simple surge protector.

I go back to the original question... is this standard action for a UPS? It seems pretty counter-productive to me.

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Just curious . . .
by Coryphaeus / December 7, 2008 6:00 AM PST

if you understand that batteries run down. How long do you expect the batteries to carry the load?

"It seems that the backed-up outlets go dead when the battery dies."

What do you expect them to do when the battery dies? Do you really understand how a UPS works?

What does a surge protector have to with your complaint?

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Unreasonable expectations?
by bdsolomon / December 7, 2008 6:16 AM PST
In reply to: Just curious . . .

I guess I was expecting that the batteries were stand-by, not part of the circuit.

I think it goes back to earlier notebook computers. They didn't operate, even when plugged in, unless you had a good battery in them. Take the battery out, or put in a dead battery, and the computer wouldn't come up. Current notebooks must have the battery in parallel or something, so that you can operate them with the battery removed, or with a dead battery in them.

I was expecting that the outlets would still work, just not with battery protection. Also, either when the battery died, or at least when an automatic test detected it at a dangerous level, an alarm would be a good idea.

The point of a surge protector is this... I have my recorder programmed, and connected. I was gone for a week. With only a surge protector, ALL would be fine if there was no power outage. Had there been a power outage, nothing would be backed up during the outage, or shortly thereafter, until the unit booted and recovered the time. After that, all future recordings (as well as one scheduled to record at the time it came up), would be made.

With the UPS, while thinking I was at least as well protected, I got nothing for most of my vacation, from the time the battery died.

So the point was that unless I am assured that the battery is good, I am more likely to get most of my recordings by using a surge protector than a UPS (if they all work like this).

I know... the other alternative is to buy new units, or new batteries, every two years. Or install the monitoring software on a computer and take it around to all of my UPS units and check their status periodically.

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Ok, here's how they work . . .
by Coryphaeus / December 7, 2008 7:25 AM PST

UPS - Contains a lead acid battery. This battery is connected to an inverter which changes the battery 12 VDC into 120 VAC. The battery is kept charged by the commercial power supply. The battery is constantly powering the computer or device, and again, constantly charged by commercial power. When commercial power fails, the battery just keeps on supplying 120 VAC to the device. Until the battery runs down. When the battery runs down, the powered device turns off. If commercial power is restored before the battery dies, then all is well and the commercial power will start charging the battery again, and the device is still running. How long before the battery dies is measured in watt hours and will vary between battery sizes. This time should be clearly stated on the box.

Surge Protector - Is simply that. It protects a device from power surges only. It has no back up capability nor will it power a device. It's simply used as a safeguard in case of a power surge or lightning hit.

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by bdsolomon / December 7, 2008 12:15 PM PST

Actually, although I used the term UPS, I thought most of the consumer versions were really Stand-by Power Systems, which do not constantly run off the battery. I thought they generally could switch to battery power in a short time (milliseconds, or at least well under a second). Models like that should not be using the battery except when needed. The downside is that they cannot be used for applications that cannot tolerate even a millisecond of downtime.

Maybe things have changed and the consumer models now do run off battery all the time. If so, I'll have to rethink whether it's worth the trouble and expense to change the battery every two years, and/or keep testing them. And since testing involves either powering them off or hooking up a PC (or both), I doubt if I'll be regularly testing them.

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I always assumed
by mementh / December 7, 2008 2:29 PM PST
In reply to: UPS vs. SPS

I always assumed that it used a capacitor system which would tolerate the issues of constant use and only pull the battery on when needed to run the system (since the capacitors would have several seconds worth of power I hope or just enough to switch and then some) because everytime I have had it happen i have heard a audible click of something engaging..

which makes more sense..

but I might be wrong? it might be a click of disconnecting the main power to prevent a spike from when it comes back?

I honestly think a capacitor system would be better suited to this and only charging the batteries for what the normal time discharge does (topping off) and the issues of spikes/brownouts if able to be handeled by the capacitors it would not need the battery..

I wonder how big a capacitor system would need to be to give the 20-30 min runtime the currect system claims to have?

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a bit wrong, how a UPS works
by lorenzo42p / April 3, 2016 1:32 AM PDT

You're mostly right, but a standard UPS actually has a relay to switch between utility power and batter/inverter. When there's no problem with utility power, the battery keeps charged, but the inverter circuit will power down and bypass by the relay.

replying to this old post because I found this page on google, I'm sure someone else will too.

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UPS Shutting Down When Batteries Died
by Tony-ExcessUPS / December 7, 2008 11:06 PM PST

Hi Everyone,

If the batteries on your APC UPS were starting to go low, or to die it still would not have dropped your load or turned off the backed up outlets.

UPS batteries don't die overnight, they slowly start loosing charge and become unable to offer a proper run time. The run time just shrinks until there is nothing left.

The unit being turned off could have meant that you did experience some sort of a power situation while you were gone or the UPS had a malfunction and shut down.

A UPS is better than a power strip/surge protector any day. A UPS will filter the power for you and will provide a run time.

It also depends on what kind of UPS you are using, some UPSs are better than others.

Shed some light on the model when you have a chance.

Also, in regards to discussion about batteries, the batteries of a UPS should be able to last 3-5 years with moderate use. 2 years is a bit on the low side, I would expect that from someone who has frequent power outages.

For most people who live in big cities, the power is pretty stable and their UPSs don't drain the batteries so much. There shouldn't be a problem having a 3-5 year life time on the batteries.

We get off lease units from the banks all the time, they're 5 years old and the batteries are still good. Two years is pretty short, I would lean towards the battery being a lower grade battery.

<a target="_blank" href=""> - APC
Battery Backup and Battery Replacement Experts</a>

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Reply to APC
by bdsolomon / December 8, 2008 2:24 AM PST

Model BE350C - a Back-UPS 350. As fara as I know, no power event (microwave clock in the other room would've reset on the slightest outage).

I can't recall the life of the unit. I'm mostly upset that the battery protected outlets were dead when there was power to the unit. Secondarily, I am upset if there IS no warning about a low battery, but I'd also be upset if said alarm couldn't be acknowledged and silenced. Remember, this is for consumer appliances rather than computers, so I do not have them monitored or even set from a computer.

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by Pat Conklin USN/SS Ret. / December 8, 2008 12:01 PM PST
In reply to: Reply to APC

I have a similar unit and the battery is "deader then a door nail". When you register with APC they will send warning emails based on model type concerning battery life and replacement. Most UPS units will have about half the outlet bank set for UPS support and the others as normal outlets (this is where your printer should be plugged in.), most also have some degree of surge protection as is standard with APC but not to the degree of a REAL surge protector. APC recommended to me plugging the UPS unit into a surge protector. My outlets work fine without the battery so what's left? Just a surge protector of about 1200-1500 joules not enough for the thunderstorm prone SE GA. Bottom line to max out protection for your electronics get an UPS and GOOD Surge protector! Have a Merry Christmas!

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yea, that's how they work...
by lorenzo42p / April 3, 2016 1:52 AM PDT

Yea... That is what happens when the battery fails. Year after year I still don't know why they would design it that way! Screen door on a submarine, make it useless. I plug a computer into an APC UPS to hopefully keep it running for a long time. The system goes down after not all that long, and what's the cause? APC.

Walmart sells cheap APC units, which I've made the mistake of buying more than once years ago. I'll never waste my money on them again.

Since then, I tried a CyberPower 950 or 1000 something, with the big blue lcd on the front (the backlight does timeout and turn off, but bright power button needs electrical tape to block bright light) It's probably 3 years old now with the original battery, still running strong, yet to have a problem. I've been running a modern computer, a large managed switch, and a firebox router, as well as a cable modem. Everything on battery backup, pulling 240-290 watts, lasts a good long while, I've always powered things down manually before an hour. I'm happy with the reliability of this UPS so far, but time will tell. I'm unsure if turning off the outlets when the battery goes bad is an APC only problem, or if this one will do the same.

replying to this old post because I found this page on google, I'm sure someone else will too.

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