Why does my PC shut down even though it's connected to a UPS?

[arni-gx]

This is strange, plugged the USB monitoring cable from the APC UPS into the PC, suddenly Win 10 said if the battery was low, even though this morning it wasn't there when I am to turn off the PC then turn off the UPS by turning off the socket switch too, the APC UPS battery icon was still full.

The warning on Win 10 tonight was that the battery was low, suddenly the PC turned off after entering Windows, so I unplugged the USB monitoring cable from the PC to the APC UPS, the PC suddenly turned on normally again, what the hell happened??


** APC BX2200MI MS (1200w), has been used since sept 2021.

 

[KedsDead]

I could be completely wrong.<< ---------------------

But I am remembering my old RC car days. Even though the batter was stored with a half charge, and slow charged to full for use, it would run the car for about 5 seconds, then just stop. Then show completely dead on the charger. Could be something similar, if the battery has never actually been used and has been sitting on full charge for a couple years. I would run what ever device is connected to the battery, on just the battery to check to see if it still holds its charge.

Not sure what setting in Windows will cause it to shut the computer down if the battery is to low, if its plugged into the wall. But I would check those settings in power also.

 

[Franz]

Clearly its a problem caused by the apc app, if your ups can hold your pc without wall outlet just disable the shut down option on app and be happy. This option most of the time can bring headaches....

 

[Jism]

Change battery's of the UPS. 3 years is over-due and those battery's lose their capacity.

They might report as being full but the current they can provide is far less now compared to when new.

I had venting battery's one day in my closed office. Got burning eyes because of it. Later i realised in what kind of danger you are as a human being when in a closed space with battery's. Since then i never put a UPS near where i'm sitting anymore.

 

[jsfitz54]

** APC BX2200MI MS (1200w), has been used since sept 2021.

Unit has 2, TWO batteries, if you test them independently you may find that ONE is dead (can't hold a significant charge) and the other is OK.
OR
They may both be weak and time for replacing both.

EDIT: You can take them out and charge them individually with a car battery charger. (a good one that won't cook the battery)
If they both can hold a charge, something on the circuit board has failed or worn out.

 

[Jism]

Yep - it's dangerous even to continue running with it. If one battery has a weaker cell; the avg charge voltage will drop. If the battery's are in series which is with most UPS's, the dumb thing will just continue to charge actually damaging the "good" battery due to the pre-set charge voltage (usually 28V or so). There's obvious some life left in them but not for a UPS anymore. Don't be silly - replace them. And stop using the UPS for now.

If they start venting the battery's, it's toxic fumes you don't want to sit nearby.

 

[ThrashZone]

Hi,
I never connect ups's to pc's
Then again I don't run pc 24/7 either.

When I buy a ups I always get at least the two year instore warranty and prefer the three year because they tend to die around that time and I get a new one if issues arise.

Replacement batteries are a lot cheaper on amazon just get the model numbers off it and search.
you can save a lot of money for the same battery apc/... used but charge 3x's more for.

 

[Jism]

https://www.cedengineering.com/userfiles/M05-021%20-%20Battery%20Room%20Ventilation%20and%20Safety%20-%20US.pdf

Starting from page 15 - you'll learn some interesting things about those battery's. Over time, they will just age, and be able to hold "less" current then when they where new, no matter how they are used, cooled, stored etc. Just the nature of the battery. On top of that when they start venting which happens when pressure inside the battery just goes beyond, they emit a toxic odor (egg-smell) and is flammable - esp with sparks or a UPS switching on or off etc.

Problem with a set of battery's in series is that if one cell of one battery goes bad, the UPS will attempt to charge until desired voltage is reached. The only problem is when one cell is weakened and cannot take any more charge the UPS will simply keep charging until the good battery is actually being damaged because of it. That will cause venting for example.

Battery's on avg last only a few years tops; they might hold or keep charge but their application no longer is solid for a UPS. When a UPS starts or kicks in, it pulls a massive amount of current from the battery's and weaker ones will make it shut down because it no longer do what it should be doing, and that is providing power.

Replace them battery's - its just not for your own safety or health, but accept that those things should be disposed as they are designed for. They can be dangerous, and there where UPS devices in the past that burned houses down.

 

[Franz]

Unit has 2, TWO batteries, if you test them independently you may find that ONE is dead (can't hold a significant charge) and the other is OK.

Never mix used with new ones or with different capacities baterries in serie, paralellal circuit is ok (not ideal, but VERY ok), but series is a bit dangerous and system never will run perfect.

Used batteries have a lower capacity as said, so depending on the depth of the discharge cycle the new one certainly will have a good charge and the used will be depleted. Lead batteries under 10,5V can take serious damage lowering even more their capacity and depending of current charge they will be killed for sure.

Speaking of current charge, those automotive charger without regulation are not suitable for too small and specially AGM batteries witch requires a lower equalization voltage. Most auto chargers hits 15.5V and most of AGM batteries only can hit 14.2V and some needs below this.

The current of charging is very important too, this never can be more than 10% of total battery capacity and for long-life is better aim to 5%

Yep - it's dangerous even to continue running with it. If one battery has a weaker cell; the avg charge voltage will drop. If the battery's are in series which is with most UPS's, the dumb thing will just continue to charge actually damaging the "good" battery due to the pre-set charge voltage (usually 28V or so). There's obvious some life left in them but not for a UPS anymore. Don't be silly - replace them. And stop using the UPS for now.

If they start venting the battery's, it's toxic fumes you don't want to sit nearby.

Venting batteries is much more an accident then a commom thing, in almost all cases are caused by overcharging and a brand new battery of top notch brand can suffer with this and it will vent too.

On UPS the charging current is very low (in normal conditions) and a battery with shorted cell will be strong enough to stuck the charging status below 100% for time enough for everyone notice something wrong and in discharge mode the voltage will drop enough to make the UPS shut down very fast.

so I unplugged the USB monitoring cable from the PC to the APC UPS, the PC suddenly turned on normally again, what the hell happened??

Guys, I'm not native english here, far from this what I know was achieved memorizing words on dictionary but what I understood from OP: UPS conected in wall outlet with power on and when USB cable is conected the pc enters in shut down mode and after that nobreak shut off too... This is tipical behaviour of UPS app

In this condition battery does nothing but receive floating charge if it was pre-charged and most of UPS brands will not charge batteries below 9~10V to prevent some adversities, in this condition the UPS must sound some alarm and not work.

 

[Jism]

You can "trick" the UPS into charging again, by holding a different battery (12V) against the polarity - and then turn it on. By tricking it it will believe the battery is within the allowed voltage and charge.

But this is never a good sollution, 99.9% it's the age already of 3 years by now.

 

[Bill_Bright]

so I unplugged the USB monitoring cable from the PC to the APC UPS, the PC suddenly turned on normally again, what the hell happened??

That is not normal - even with failing batteries.

It seems several things are happening.

A battery can output its rated voltage but still be faulty - not have enough current behind it to carry a load. This can trick the UPS monitoring circuits in to thinking the battery is still good, but as soon as a load is placed on the UPS, output drops and the connected devices suddenly loose power. It sounds like that is one of your problems there.

Many UPS have setting options in their configuration menus to automatically shut down the UPS when battery charge levels drop below some threshold (typically set by "runtime left" on battery). This is set in the UPS software that runs in Windows. By unplugging the intercommunications cable, the UPS "may" (I'm kinda-sorta guessing here) no longer be receiving the instruction to power off, then decides to restore output power.

The odd part is, the PC turning back on by itself after removing the UPS cable. That is NOT normal.

By default, computers/motherboards have a BIOS Menu setting that keeps the computer "off" once power is restored from a power outages. But this setting can be changed by the user to tell the computer to automatically boot once power returns. This is typically done for remote "unattended", mission essential systems. It is so a technician does not need to make a road trip in the middle of the night after a power outage just to boot the computer. Did you change that setting in the BIOS Setup Menu?

***

As mentioned above, 3 years is the typical "average" life expectancy of UPS (SLA) batteries. It can actually vary widely from 2 to 5 years or even longer depending on how they are used. If the UPS kicks over to battery frequently, the load is heavy, and the time on battery (depth of discharge) is long, the batteries tend to have a shorter life.

High ambient (room) temperatures can speed up aging too.

SLA batteries do NOT suffer from memory effect so if left unused (or constantly in any charge state), there is not a problem of memory - unlike other battery chemistries.

HOWEVER, the chemical reaction inside these batteries NEVER stops. This is why these SLA batteries (which includes car batteries too) have a "shelf-life". That is, they will grow old and wear out just sitting on the shelf, even if never used.

For that reason, buy your replaces from a place with a rapid turn-over to ensure you get the "freshest" batteries possible.

FTR, I never, as in NEVER EVER buy replacement batteries from the UPS maker. The UPS makers are not battery makers. So they buy from OEMs. The UPS makers then charge outrageous prices for the same batteries you can buy elsewhere. Often, it is the exact same battery that APC, CyberPower, Eaton/Tripp Lite uses that they just slapped their sticker on!

I buy my UPS batteries from BatteryWholesale, Battery Mart, Batteryplex, RefurbUPS, Walmart or Amazon - depending on who has the best price on that day. Note today one distributor will price high with free shipping and the next day price low but with additional shipping charges added. So be sure to factor in shipping, which can be significant, but sometimes free.

Just make sure you get the same voltage. The amp/hour rating can be higher however, for longer run times, but not lower. For example, it the current cells are 12V 7.2AH, I always go with 12V 9AH. The physical dimensions are normally the same (or close enough) but double check to be sure. And last, make sure you get the correct terminal size. There are inexpensive adapters but typically space inside the UPS battery compartment is too limited.

F1 vs F2 terminal connector size
F1 Terminal – 3/16” (0.187”, 4.8mm) wide
F2 Terminal – 1/4" (0.25”, 6.35mm) wide

If your UPS battery consists of two or more battery cells, they will be strapped in parallel, series or series/parallel configurations to achieve a specific output voltage. This strapping is typically done with one or more small jumper or interconnecting cables. Don't discard those straps (or any plastic framework) the old battery may have used. Save them to use to assemble your new battery. I recommend taking a photo of the battery wiring before disassembly to use as a guide when assembling the new cells into the new UPS battery.

What's this cell vs battery stuff? A single cell can be "a" battery. Or, several cells put together can make up "a" battery. So, for example, if you have a flashlight that uses 4 AA batteries, individually each AA battery is a single cell. Insert the 4 AA cells into the flashlight and now, working together, they have become "one" battery, made up of 4 cells. Clear as mud, huh?

To make it more confusing, standard SLA UPS batteries, like this 12V 9Ah battery actually have 6 cells internally (just like a car battery). So, when this 12V 9Ah battery is used separately, it is a single-cell battery. But strap two of those 12V 9Ah batteries together, they become one 2-cell battery - even though there are 12 internal cells. Totally confused now? No worries. It really does not matter. Most people just call them batteries and that's fine.

 

[Jism]

Ive learned that hot transformers, also are the culprit to avg higher battery temperatures. Esp the cheap UPS devices have really tight transformers that run easily into the 60 degrees while the battery's are right next to it. Adding a small fan is kind of essential.

 

[jsfitz54]

@Bill_Bright

Thanks for going in-depth for the OP. I hope they read it carefully and twice.

 

[Bill_Bright]

Heat is the bane of all electronics. So yes, the heat from the transformers, just like ambient heat, can affect the life of the batteries. But typically, the transformers should not get very warm, unless working hard for extended periods when charging discharged batteries. Ideally, that should not be very often.

I note some UPS have internal fans. I hate fan noise and in my experience, UPS fans are low quality, thus noisy. And I really hate fan noise. If an UPS needs a fan, I think it sad the UPS makers do not include large, "quality" fans. Large fans tend to move more air at lower RPMs. Lower RPMs typically results in less objectionable fan noise. And "quality" fans tend to have precision bearings. Precision bearings roll more smoothly, creating less friction and vibrations that create annoying fan noise. Did I mention I really REALLY hate fan noise?

Adding a small fan is kind of essential.

The problem with "adding a fan" is where are you going to add it to do any good. Most UPS are closed units. Any vents are small and not designed to promote a "flow" of cool air through the case to exhaust the heat out. And then, what about fan noise. Some people don't like it.

So typically, the best we can do is to make sure there is sufficient space around the UPS for proper ventilation to allow any heat to radiate out and away.

 

[Jism]

It's usually with the cheaper UPS devices, where the transformer is quite small for it's task, followed with battery's right next to it.

If your computer draws a good amount, depending on the working of the UPS, most of that current can flow through the transformer, thus adding heat.

I've had a small UPS that produced quite some heat - too hot to touch kind of transformer; with side vents and room for a tiny fan. You can install a noise free fan, to at least provide some form of cooling.

 

[Bones]

If the battery sits unused and also hasn't been charged for long enough, it will eventually build up a voltage charge on it's own that shows it being OK but once a load is applied, voltage goes down instantly.
It's called "Surface Charge" when you talk about a battery.
If the battery is bad you can still have it show a good voltage but does what's described when a load is applied.

Same thing can happen if you charge a bad battery - It can show itself having a good charge but go flat when load is applied due to whatever is wrong with it.

Same basic effect as when an old WWII submarine had batteries that were "Flat".

That's the best description of it I can give here.

 

[jsfitz54]

If the battery sits unused and also hasn't been charged for long enough, it will eventually build up a voltage charge on it's own that shows it being OK but once a load is applied, voltage goes down instantly.
It's called "Surface Charge" when you talk about a battery.
If the battery is bad you can still have it show a good voltage but does what's described when a load is applied.

Same thing can happen if you charge a bad battery - It can show itself having a good charge but go flat when load is applied due to whatever is wrong with it.

Same basic effect as when an old WWII submarine had batteries that were "Flat".

That's the best description of it I can give here.

So if you charge both batteries independently and let them sit for 2-3 days, one may show 12vdc and the poor/bad one may show 7vdc which is a fail.
Some good chargers will indicate that the battery is bad. Some good chargers will desulfate a battery.
You never take it off the charger and test, that's a false read.

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[Jism]

But since most UPS are having battery's in series, the voltage would be 12V + 7V = 19V DC and it attempts to keep charging it untill 28 ~ 29V is reached.

And thats where cheap UPS devices go bad.

 

[jsfitz54]

But since most UPS are having battery's in series, the voltage would be 12V + 7V = 19V DC and it attempts to keep charging it untill 28 ~ 29V is reached.

And thats where cheap UPS devices go bad.

Test each battery on it's own. I've said it twice.

 

[Bill_Bright]

If the battery sits unused and also hasn't been charged for long enough, it will eventually build up a voltage charge on it's own that shows it being OK but once a load is applied, voltage goes down instantly.

True. You can even see this effect in a simply flashlight (torch). It will shine bright for couple seconds then quickly dim away. Let it sit for awhile and it will recharge itself a bit. But again, quickly dim.

So if you charge both batteries independently and let them sit for 2-3 days, one may show 12vdc and the poor/bad one may show 7vdc which is a fail.

Also true.

But since most UPS are having battery's in series, the voltage would be 12V + 7V = 19V DC

"Many", yes. I don't know about "most". I have seen many multi-cell UPS strapped in parallel and series-parallel too. Two 12V batteries strapped in parallel will have 12V combined output, but higher current (wattage) capability for bigger loads and/or longer battery run times.

I have an APC 1000VA Back-UPS here that uses 4 x 6V 12Ah batteries strapped in series/parallel. That is, first, they are strapped in pairs. Pair 1 is strapped in series to create a 12V output. Same with Pair 2.

Then Pair 1 and Pair 2 are strapped in parallel to create one big 12VDC battery. As as side note - this is my oldest UPS. It is now over 30 years old and on its 4th or 5th set of batteries. It sits in my garage as a battery backup for my garage door opener. It is in the garage because its transformers are old and hum. Plus the case is that old cream color computers used to be - only it has yellowed even more. But suitable for a garage.

In your 12V + 7V example, that really assumes the 7V is an actual 7V (though 6 or 8 would be more likely) battery by design, and not a faulty 12V battery. Many aging batteries die because they develop a short or partial short between the internal cells. That short could result in dragging down the 12V too.

In any case, it typically is not advisable to strap different voltage batteries in series - especially rechargeable batteries as that can really confuse the charging circuits.

Test each battery on it's own. I've said it twice.

Agreed. However, this is not always a simple task for most users. Like pretty much ALL power sources, they need to be tested with a realistic load. That applies to car engines, generators, power supplies, and batteries too. A dedicated battery tester like this will have a "dummy" load built in. But you cannot use that tester for these SLA batteries. You can use a multimeter but most multimeters don't have built in dummy loads either.

I have a couple 100W 12 Ohm (set to 8 Ohm) ceramic resistors like these I used to use when repairing/testing audio amps to simulate having 8 Ohm speakers attached. I strap one of these to the battery terminals for a load. Then measure the battery. When properly and fully charged, a good 12V SLA battery "should" read ~13VDC. Chargers always charge at a voltage slightly higher than the batteries rating. If not, the battery will never fully charge.

It "should" hold that charge fairly steady and slowly decay from there over quite a few minutes (depending on the AH rating and actual load). If fully charged it reads less than 12, the battery is not good. If it quickly drops below 12 and keeps falling, it is not good.

A fully charged "good" battery should hold a charge at or very close to 12V for several days, even weeks before showing any significant drop in voltage.

BTW, even though those 100W ceramic resistors are big and hefty, with a good battery, they will get hot enough to burn your fingers in a pretty short period of time. Take care where you set them while testing.

 

[Jism]

If you have zero proper testing equipment for UPS battery's - a voltmeter is not going to give you an exact measure. If the UPS fails at a certain load to "uphold" then it means the battery's are unable to.

As i said; they can be re-used for different tasks but no longer a UPS load - or the load has to be that small that they can still take it.

I've learned quite a lot about these things - most important is that to not fuck around with battery's or not skimp out on budget(s).

 

[ThrashZone]

Hi,
Damn 21 post and no op responding since the thread was created :/

Basic trouble shoting
Disconnect the data cable from pc
Unplug the ups from the wall outlet and read the displays time left.

 

[Bill_Bright]

I have a 100W incandescent light bulb in a desk lamp. I will often test an UPS by plugging that lamp into the UPS, then unplugging the UPS from the wall. Even a small UPS should support that load and run for many minutes. But if the batteries are bad, even with a large capacity UPS, typically the UPS shuts down immediately, or within a minute or two.

 

[Bones]

So if you charge both batteries independently and let them sit for 2-3 days, one may show 12vdc and the poor/bad one may show 7vdc which is a fail.

That falls in line with what I had said myself. Either it's going to charge properly or it's not with the listed symptoms.

Some good chargers will indicate that the battery is bad. Some good chargers will desulfate a battery.

In the case of chargers that say it's bad you still have to let it charge overnight and restest to get accurate results.

For desulfation, all that does it break sulfation loose from the bottom of the battery cell, the sulfation itself is still in the cell like before, just not where it was. To actually get rid of sulfation you'd have to drain, flush and fill the battery cell(s) so it's truly gone..... Until next time.

I have one right now with a bad/sulfated cell and I'm going to recondition the battery later so it can keep going.

You never take it off the charger and test, that's a false read.

You have to deal with the battery's surface charge and a simple voltage check isn't enough right off the charger anyway - It's going to show itself as "Good" that way.
That's when you load test it to see if any cells "Fall out" and if you have a bad one, you'll see it.

I'll normally load it down a few times during testing.
First loading is to get rid of the surface charge and also to see how far it goes down underload straight off the charger.
Using my battery load tester, I'll place a load on it for about 10 seconds, then remove the load to see how much/far it springs back. That will remove the surface charge and give a clearer picture of the battery's overall condition.
I'll wait a few moments to let my tester cool down (Hand held unit made by Mac tool) and then go for another 10 second load, repeat and so on until the results are more or less consistent to fully settle the battery into it's true state.

Only takes a few times to see it and know what you'll need to do from there.

Guys, I used to work on industrial trucks (Forklifts and other electrical based vehicles) and I've dealt with my fair share of batteries of all sizes, voltages and I've even repaired a few too.
Ever worked on/fixed a battery with a torch before?
I have and unless you know what you are doing (As in trained for the job) - Don't try it yourself.

 

[arni-gx]

I could be completely wrong.<< ---------------------

But I am remembering my old RC car days. Even though the batter was stored with a half charge, and slow charged to full for use, it would run the car for about 5 seconds, then just stop. Then show completely dead on the charger. Could be something similar, if the battery has never actually been used and has been sitting on full charge for a couple years. I would run what ever device is connected to the battery, on just the battery to check to see if it still holds its charge.

Not sure what setting in Windows will cause it to shut the computer down if the battery is to low, if its plugged into the wall. But I would check those settings in power also.

apc bx 1100 ci ms is connected only to my LCD, apc bx 2200 mi ms is connected to my PSU, the monitoring usb cable is only connected into apc bx 2200 mi ms, but for the last couple days, it has been unplug from my ups apc bx 2200 mi ms..... so far so good, its very strange...

both my ups apc is never used 24/7 since sept 2021....

Clearly its a problem caused by the apc app, if your ups can hold your pc without wall outlet just disable the shut down option on app and be happy. This option most of the time can bring headaches....

yeah, i dont know why the app monitoring from win 10 for my ups apc, is suddenly has weird alarm....

my ups apc is never show that the battery it has low capacity....

So like this, in September 2021, I replaced a new battery (for the umpteenth time) for the UPS APC BX 1100 CI MS at the UPS APC distributor in my city, during the replacement process which took several days, I then bought the UPS APC BX 2200 MI MS , which I directly connected to my Seasonic 850w PSU, then I plugged the USB monitoring cable into the UPS APC BX 2200 MI MS, then replaced the new battery in the UPS APC BX 1100 CI MS, then I plugged it into my LCD & speakers.

Well, just a few days ago, suddenly the UPS APC battery icon suddenly went LOW on my Windows 10 (which was just a clean install in December 2023 because I replaced the HDD with an NVME SSD), which made my PC suddenly shut down, but that's when I unplugged the monitoring cable. USB from my casing which connects to the UPS APC BX 2200 MI MS, my PC suddenly turns on automatically, runs normally, until now.

Even though my PC restarts manually, it is on OFF every day, because my PC is rarely used 24 hours a day, the UPS APC BX 2200 MI MS still runs normally, I even had time to test whether the UPS APC BX 2200 MI MS can still turn on with the power cable I unplugged it from the socket and it turned out it was still working normally, although the alarm didn't sound all the time.

strange right??