PC Peripherals UPS power consumption when idle

[n1r0]

Are all UPS brands taking this much power and doing nothing?

They're NOT doing nothing. A UPS has circuitry that, at minimum:

• keeps the battery fully charged to be able to provide max backup time
• monitors AC mains for voltage fluctuation to disconnect it from PC and power it via battery+inverter
• turns on internal fan if it overheats

So saying they do nothing but sit and consume electricity, is like saying car insurance does nothing because you are a careful driver.

Even if you disconnect power to the UPS when your PC is off, this circuit will still be running off the battery. So if you go down this road, you'll be killing your battery even faster since Lead Acid batteries have a finite number of charge-discharge cycles.

Given your general hatred for UPSs, have you considered switching to a laptop? You can hit two birds with one stone:

1. Save on power bill as laptops are generally more efficient than desktops
2. No UPS purchase cost + charging cost + battery replacement cost + save on AirCon running cost

I wish we could directly hook up batteries to PSUs and do away with UPSs altogether. Good for the environment as we can reuse old car/truck batteries that are good but can't provide the high current (400+ amp) required for starter motors.

 

[Heisen]

Every electronic design is a trade off, the UPS for PC's are generally tuned towards one goal, which is to instantly switch the power from mains to battery and that too even when your PC is consuming 600 watts or more, also can't send DC directly, it has to convert into AC first. This readiness will require some components to be always working in active state which causes high standby power consumption.

There are transformer losses which can't be avoided, but if they decide to do transformer-less design, they may gain efficiency but may loose something somewhere else, like the quality of AC output, or they loose quick transient response time when the load instantly demands more power, etc etc. To improve on all this they may have to use more components and cost will go up, generally in high power applications transformers are preferred.

So its not so easy to provide sudden burst of high power to something in case of power out, while also being very efficient, it can be done no doubt but then it won't be cheap.

 

[goDofWar_skr]

Even if you disconnect power to the UPS when your PC is off, this circuit will still be running off the battery. So if you go down this road, you'll be killing your battery even faster since Lead Acid batteries have a finite number of charge-discharge cycles.

Is this true even if the UPS is turned off?
I usually shut down my gaming pc, then turn off the UPS and disconnect it from the main power before going to sleep every night...

 

[n1r0]

Is this true even if the UPS is turned off?
I usually shut down my gaming pc, then turn off the UPS and disconnect it from the main power before going to sleep every night...

Yes, this is what I've observed in both my UPSs, when both UPS switch + wall switch were off. Sometimes the fan would be running as well.

So try this: switch off the wall switch powering the UPS.
Turn on the UPS (you may have to press and hold the switch for longer)
If the UPS can turn on purely via battery power, the batteries weren't completely disconnected via a relay or something right? (This switch isn't physical, it's an electronic one)

This is my guess based upon my observation. If you have the means to test and confirm it, I'd welcome it. Lead acid batteries can be stored for 6 months before needing a recharge. If the voltage is dropping that means there's some parasitic draw.

The manual says never cut off power TO the UPS. Only use the switch on the UPS itself to turn on/off the PC.

 

[goDofWar_skr]

The manual says never cut off power TO the UPS. Only use the switch on the UPS itself to turn on/off the PC.

Yes, even I saw this warning written on a sticker pasted on top of my UPS, which I thought was very strange.
My understanding was that while I'm not using my PC, I don't need the backup to power anything. So why keep the UPS on and unnecessarily charge the batteries..
Now this discussion has piqued my interest.. Need to check/study more about this..

 

[BullettuPaandi]

The manual says never cut off power TO the UPS. Only use the switch on the UPS itself to turn on/off the PC.

Never knew this. Is there any reason, though? Why is there not a manual switch to turn off the UPS from using its battery?

I don't have a dedicated UPS for my PC. I'm using with a household inverter, which also doesn't completely turn off after switching(using the electrical one) to off.

 

[Ssreek]

I too have such info on UPS.

 

[rsaeon]

Never knew this. Is there any reason, though? Why is there not a manual switch to turn off the UPS from using its battery?

Some APC models have a physical connector for the battery in the back, it remains disconnected after manufacturing until the end-user connects it, presumably to prevent the battery from draining out while in storage until it is sold:

As for why, I'm not sure — maybe to allow for a coldstart when required as @n1r0 mentioned. It could also be to make sure the battery is always charged, since you do need to maintain a floating charge for lead acid batteries. The whole point of a UPS is for emergency power in the case of an outage so having the batteries always topped up is essential.

I wish we could directly hook up batteries to PSUs and do away with UPSs altogether. Good for the environment as we can reuse old car/truck batteries that are good but can't provide the high current (400+ amp) required for starter motors.

I've done this and it's very efficient — I use a DC-DC ATX power supply that's connected to a 12V DC-DC converter which is then connected to the battery. So the fluctuating battery voltage is stablized with the 12V DC-DC converter which supplies the DC-DC ATX power supply.

The only downside is finding high power DC-DC ATX power supplies, the ones available in india are leftovers from the mining days and are just 160W for total system power:

https://www.amazon.in/PiPlus%C2%AE-24Pin-Switch-Supply-Module/dp/B09RN1TTHZ/

There's higher wattage ones available online that can be imported, places like https://smallformfactor.net/forum/ has discussions about them.

 

[n1r0]

Never knew this. Is there any reason, though? Why is there not a manual switch to turn off the UPS from using its battery?

Because then you would have to flip 2 switches instead of one. Also lead acid batteries should be charged slowly. The laft 20% takes a long time to charge. Fast charging damages them. The first 80% can get charged really fast, but it may take a total of 24 hours to completely charge it

Some APC models have a physical connector for the battery in the back, it remains disconnected after manufacturing until the end-user connects it, presumably to prevent the battery from draining out while in storage until it is sold:

Are batteries in other UPSs disconnected when bought new? That would confirm whether they consume energy when disconnected from mains or not, else they would arrive with dead batteries that cannot be charged.

I've done this and it's very efficient — I use a DC-DC ATX power supply that's connected to a 12V DC-DC converter which is then connected to the battery. So the fluctuating battery voltage is stablized with the 12V DC-DC converter which supplies the DC-DC ATX power supply.

Nice!

 

[lockhrt999]

They're NOT doing nothing. A UPS has circuitry that, at minimum:

• keeps the battery fully charged to be able to provide max backup time
• monitors AC mains for voltage fluctuation to disconnect it from PC and power it via battery+inverter
• turns on internal fan if it overheats

Justify why it needs 20W to do all that (minus battery charging). Also explain why other UPS brands don't get this warm when not in use.

Given your general hatred for UPSs

Na, you should read the last thread. My hatred is limited to APC only. I find them overrated. I have used a dozen UPS brands and owned half a dozen of them. APC does the most itemgiri.

Even if you disconnect power to the UPS when your PC is off, this circuit will still be running off the battery. So if you go down this road, you'll be killing your battery even faster since Lead Acid batteries have a finite number of charge-discharge cycles.

There's a fallacy in this statement. APC keeps the batteries warm, as it has to dissipate those 20W somehow. My batteries never lasted more than 2 years in APC UPS despite keeping it plugged in all the time. The batteries age faster in APC.

 

[n1r0]

There's a fallacy in this statement.

Sorry, what's false in what I said? Please provide proof as well.
And while you're at it, look in to what trickle charging is and how much power it consumes.

 

[rsaeon]

The batteries age faster in APC.

Two years is about what I've always known UPS batteries to last, especially with 100+ power cuts per year. But then I started oversizing the batteries and I'm seeing way battery more life than I ever did, and this should work with any brand UPS, not just APC.

My dual battery 750VA APC has only a ~40W load and it runs for 4+ hours, I bought it used from someone who used it for CCTV. It's still on its original 2019 batteries, so that's 4+ years of life so far.

I also have a 850VA Home UPS by APC, it's connected to a 150Ah tall tubular battery from 2017 (I purchased that half price in 2018 from someone on OLX). Today it powered a 1HP water pump for 30mins and about 100W of load for three hours during a scheduled power cut and battery voltage dropped to 11.47V (more than 80% used/depth of discharge/DOD) before power was restored (battery cut-off is at 11.1v or about 5% DOD).

Last year I did a full capacity test (to 10.5v or 100% depth of discharge) on the battery at 40W (just networking/wifi) and I got a capacity of 143AH from that then-five-year-old battery:



This is because it's barely being used with 40W load, so it's stupidly oversized and as a result lasts longer than any power cut we've had over years — 42 hours and 41 minutes as shown above.

I have similar experiences with a tiny 250VA Microtek inverter and a 1600VA Sukam inverter, oversizing the batteries results in significantly battery life. But you do need to keep in mind that one of the conditions to safely oversize batteries is that the UPS/Inverter needs to have a cooling fan for prolonged operation.

 

[lockhrt999]

Sorry, what's false in what I said? Please provide proof as well.

Read this thread and https://techenclave.com/threads/ups-for-someone-who-hates-apc.215197

Everyone here on the forum (in other threads too) has said APC runs warmer compared to other UPS. That does mean high-power usage on APC on idle. I don't expect it to consume 0W, but 20W is a lot. It's Rs. 2k per year I'm paying in light bills.

For anyone using an APC, I'd suggest unplugging it when not in use. I know keeping it plugged in 24×7 sounds nice in theory, but as everyone is saying here, APC keeps your batteries warm, which in itself is bad for them. You'll end up saving money on battery and electricity.

Two years is about what I've always known UPS batteries to last, especially with 100+ power cuts per year. But then I started oversizing the batteries and I'm seeing way battery more life than I ever did, and this should work with any brand UPS, not just APC.

In a whole year, I might use up to only 2 hours of UPS backup in total. That's it. There aren't many power cuts outside the Monsoon. Still, batteries won't last longer than 2 years. I'm using standard Exide 7ah batteries. Plugged in 24x7. In my experience, batteries do last longer in other brands of UPS (for my light-weight case).

 

[ze_cook]

For anyone using an APC, I'd suggest unplugging it when not in use. I don't think keeping it plugged in 24×7 sounds nice in theory, but as everyone is saying here, APC keeps your batteries warm, which in itself is bad for them. You'll end up saving money on battery and electricity.

I won't suggest this. Lead acid batteries need float voltage to compensate for their self discharge. Also, even with the UPS turned off, the circuits to maintain the system are still powered on, and that will slowly discharge your batteries. IMO, 20w isn't a lot of power, and most of that dissipation would be from the transformer winding loss.

As with everyone saying APC keeps the batteries warm, I don't see any data that suggests that the generated heat reaches the battery compartment, or that it's not the same with other manufacturers.

 

[n1r0]

Read this thread and https://techenclave.com/threads/ups-for-someone-who-hates-apc.215197

That has no bearing on what I said: More discharge cycles = faster battery wear = more frequent battery replacements. This is fact.
If you're refuting this, prove it.

For anyone using an APC, I'd suggest unplugging it when not in use. I don't think keeping it plugged in 24×7 sounds nice in theory, but as everyone is saying here, APC keeps your batteries warm, which in itself is bad for them. You'll end up saving money on battery and electricity.

This isn't a solution, as stated above in this thread. Please go through the industrial practises of various brands which indicate this shouldn't be done. Refer my previous statement.

Everyone here on the forum (in other threads too) has said APC runs warmer compared to other UPS. That does mean high-power usage on APC on idle. I don't expect it to consume 0W, but 20W is a lot. It's Rs. 2k per year I'm paying in light bills.

Do you know how hot car batteries get sitting in the engine bay? While temperature does affect batteries, they can still last 4+ years IF you understand their limitations and don't abuse them.

In a whole year, I might use up to only 2 hours of UPS backup in total.

I repeat: why don't you switch to a laptop? You'll have much lower running costs and don't need a UPS

170/month is worth it to protect our data and hardware. Is it better if it were 0? Yes, of course.
But you can't have a 100% efficient system. There's no free lunch (except in schools)

Else if you really need a desktop, here's a possible solution:

• Add a switch to disconnect the batteries from the UPS
• Switch off mains supply to UPS when PC is off
• Switch off the batteries

This should save your battery and power bill

 

[ze_cook]

In a whole year, I might use up to only 2 hours of UPS backup in total. That's it. There aren't many power cuts outside the Monsoon. Still, batteries won't last longer than 2 years. I'm using standard Exide 7ah batteries. Plugged in 24x7.

IMO, if you're not worried about a sudden shutdown, you can forego power backup altogether. 2 hours in a year is 99.97% uptime, and even aws compute has highest availability at 99.99% uptime.

 

[lockhrt999]

IMO, if you're not worried about a sudden shutdown, you can forego power backup altogether. 2 hours in a year is 99.97% uptime, and even aws compute has highest availability at 99.99% uptime.

Buddy, it's not a single 2-hour continuous outage once in a year. It's more like multiple 10-30 seconds outages per week. The government frequently reminds us that we are still a developing country.

As with everyone saying APC keeps the batteries warm, I don't see any data that suggests that the generated heat reaches the battery compartment, or that it's not the same with other manufacturers.

My last set of batteries got boiled over. And I have acid stains on my desk. I checked the charging voltage, and it's within the range. The only factor that could have made the batteries to leak acid is the heat. (And did I mention batteries are mounted on their sides and not upright?)

Certainly, if I keep batteries outside the UPS like what @rsaeon has done, it'll increase their life.

IMO, 20w isn't a lot of power

20W doesn't look much on paper.

But,

• 20W = 175 units per year (20W × 24H × 365D)
• It's 1/4th power consumption of my computer in terms of units.
• A front load washing machine or a dishwasher also consume similar power in a year.
• It's equivalent to one month's power consumption of a typical AC unit mounted in an apartment.
• Its annual power consumption costs me more than one month's electricity bill.

Tell me, how I make peace with that? There's no problem with money. However, paying for one more month every year just to have a UPS in the loop sounds inefficient to me. Check the math at the bottom of this post, too.

That has no bearing on what I said: More discharge cycles = faster battery wear = more frequent battery replacements. This is fact.
If you're refuting this, prove it.

As I have previously mentioned, I seldom need to fully discharge the batteries. My batteries stay above 90% charged all year around. Still, they don't last over 2 years.

This isn't a solution, as stated above in this thread. Please go through the industrial practises of various brands which indicate this shouldn't be done. Refer my previous statement.

It might be true for other UPS brands. Again, I'm not refuting with what's written in the manual. My concern is only for APC. APC has the most crappy engineering there is in the UPS space. It has made some egregious engineering blunders while designing the UPS. It's so stupid that it makes me want to pull my hair. I have mentioned many of them previously on this forum.

Do you know how hot car batteries get sitting in the engine bay? While temperature does affect batteries, they can still last 4+ years IF you understand their limitations and don't abuse them.

1. Vehicle batteries have breathing valve.
2. The chemistry is also different.
3. You might not have noticed it, but vehicle batteries aren't being charged for 24×7.
4. Vehicle batteries have some space to breathe. Batteries in APC UPS locked up in a pressure cooker like compartment without any vent.
5. Vehicular batteries are mounted vertically. Why don't you mount that acid containing battery on its side like an APC UPS and kindly report back to us? @rsaeon mate, can you place your 150Ah on its side? What a great idea! APC can't possible wrong, right? I think, it might have just cured the cancer.

I repeat: why don't you switch to a laptop? You'll have much lower running costs and don't need a UPS

Why don't you stop preaching like an Apple snob? Your solution sounds like “You-are-holding-it-wrong”. Parroting lines from a manual might not be in our best interest.

Let's do the Math,
Pair of batteries costs = 1800
Batteries last = 2 years
Money to power UPS 24×7 for 2 years = Rs. 4000 (175 units per year x 2 years x Average unit price)

So, you want me to spend a full 4k in power bills to save the lives of batteries worth only 1.8k? Doesn't it sound like the insurance premium is pricier than the insured amount itself?

If I unplug UPS for 12 hours daily (when I'm not at the computer) I save 2k in power bills. That alone buys me an extra set of batteries. And no, UPS doesn't pull more than 20W if I resume its power after a break of 12 hours, I have checked.

So my suggestion still stands for anyone using APC and not suffering from far too many power outages. Unplug the UPS when not in use.​

The equation is simple,

• Unplug UPS when not in use, and this practice will literally give you a pair of new batteries for free every 2 years (through the savings in power bill).
• To hell with the hypothetical longevity of batteries if I'm getting new batteries for free.
• Plus, it saves another Rs. 1800 on batteries every 2 years.
• Not to mention, if someone is using an AC to cool their room, unplugging the UPS would yield further savings in power bill.

Refute on that!

 

[Ssreek]

So my suggestion still stands for anyone using APC and not suffering from far too many power outages. Unplug the UPS when not in use..

Time to see if my Microtek UPS is doing the same thing. Waiting for Polycab 16A smart plug to be back in stock.

 

[Heisen]

My last set of batteries got boiled over. And I have acid stains on my desk. I checked the charging voltage, and it's within the range. The only factor that could have made the batteries to leak acid is the heat. (And did I mention batteries are mounted on their sides and not upright?)

Did you replace your batteries with original APC batteries?

 

[n1r0]

Refute on that!

Ah I see what the problem is: you have a partial understanding of things and love jumping to conclusions.

Let's start with you calling me an Apple fanboy. I have never owned, nor plan to ever own an Apple product for the simple reason that they are overpriced. If you recall, iPhones had Bluetooth but only for audio, not for sharing files. Even then I thought people who bought them were iDiots (no offense to them, if you have money to burn, burn awaym but you're paying more for less)

Now, allow me to refute your points one by one:

Vehicle batteries have breathing valve.

Breathing valve, no. It is an emergency pressure relief valve. When overcharged the battery produces Hydrogen gas and the internal pressure increases. To prevent explosions there is a mechanism that vents the excess gas and then closes. It does not allow the battery to breathe in ambient air. Very similar to a pressure cooker: if the weight gets stuck for some reason, the emergency valve opens to dissipate internal pressure, else the cooker will explode.

The chemistry is also different.

Both UPS battery and car battery have the same battery chemistry: Lead electrode + sulphuric acid electrolyte. They are however designed for different applications. Car batteries need high current for a small duration. UPS needs low current for a longer duration. Hence cars use flat lead plates while home UPS ones use tubes (hence tubular batteries)

You might not have noticed it, but vehicle batteries aren't being charged for 24×7.

Yes. The purpose of a car's battery is to power the ECU and fuel pump, and provide a short burst of high current to start the engine. Thereafter the electricity produced by the alternator not only tops off the battery and stops once fully charged. Charging a battery constantly would be a waste of fuel + damages the battery as well. Newer cars with "smart alternators" are programmed to save fuel so much so that they don't even recharge the battery properly.

Vehicle batteries have some space to breathe. Batteries in APC UPS locked up in a pressure cooker like compartment without any vent.

Batteries are a closed system. They don't need "space to breathe" or air to work properly. And UPS battery compartments are not air tight, I can't imagine how you arrived at that conclusion.

Vehicular batteries are mounted vertically. Why don't you mount that acid containing battery on its side like an APC UPS and kindly report back to us? @rsaeon mate, can you place your 150Ah on its side? What a great idea! APC can't possible wrong, right? I think, it might have just cured the cancer.

This + your previous point: Home inverter UPS and car batteries may use the same chemistry, but their design varies sligtly.

1. Flooded Lead Acid battery: this is what home inverters use. They are easily recognizable by the electrlyte level indicator on top. When overcharged, water splits into Hydrogen and Oxygen and escapes as this is not a sealed system. Hence you have to top it off with distilled water to the correct level
   
   
   
   
   
   
2. Sealed maintenance free battery: this is what cars and bikes use. Guess why? Mounting a battery upright does not mean electrolyte can't spill out. When turning or driving on rough roads, the battery experiences forces in various directions. With bikes, there is leaning also whilst turning. If acid could spill out as easily as you imagine, no one would be using vehicles.
   
   
   
   
   
   AGM/VRLA batteries can be mounted in ANY orientation. This is what bikes and UPS use.
   
   
   

Why don't you stop preaching like an Apple snob? Your solution sounds like “You-are-holding-it-wrong”. Parroting lines from a manual might not be in our best interest.

The manual exists for this precise reason: to prevent oversmart consumers like yourself from deviating from the designed usage scenario. Next you will say it is far cheaper to run a petrol engine on kerosene.

Let's do the Math,
Pair of batteries costs = 1800
Batteries last = 2 years
Money to power UPS 24×7 for 2 years = Rs. 4000 (175 units per year x 2 years x Average unit price)

So, you want me to spend a full 4k in power bills to save the lives of batteries worth only 1.8k? Doesn't it sound like the insurance premium is pricier than the insured amount itself?

The purpose of a UPS is to protect your PC, not the batteries. To provide max backup time to allow you to save any important data and safely shutdown. To do this, the battery has to be kept at 100% charge state. And since you decided to make it personal, you sound like a moron who thinks getting insurance/wearing helmet & seatbelt is only to prevent getting fined by cops. It's cheaper to bribe the cops and get away than paying expensive insurance premiums. You missed the WHOLE point of protection.

If I unplug UPS for 12 hours daily (when I'm not at the computer) I save 2k in power bills. That alone buys me an extra set of batteries. And no, UPS doesn't pull more than 20W if I resume its power after a break of 12 hours, I have checked.

So my suggestion still stands for anyone using APC and not suffering from far too many power outages. Unplug the UPS when not in use.​

Do you have any supporting data from personal experience of this where your batteries lasted >2 years?
If your batteries are already lasting for only 2 years, then doing this will reduce it further. What you are saying is a hypothesis. What I am stating is a fact of battery chemistry.

The equation is simple,

• Unplug UPS when not in use, and this practice will literally give you a pair of new batteries for free every 2 years (through the savings in power bill).
• To hell with the hypothetical longevity of batteries if I'm getting new batteries for free.
• Plus, it saves another Rs. 1800 on batteries every 2 years.
• Not to mention, if someone is using an AC to cool their room, unplugging the UPS would yield further savings in power bill.

The only thing hypothetical here is your claim that the battery will last longer. If you had actually conducted this experiment, you would realize that the battery would wear out even sooner than 2 years. But you just want to feel good about your big brain idea, and call people trying to help you Apple snobs. Lead acids have a very low number of charge-discharge cycles. With this method you are using up a part of that cycle every single day. These are not deep discharge batteries either.


Forget everything, just tell me why you ignored the perfect solution I provided to your problem, and decided to go on a baseless rant:

• Add a switch to disconnect the batteries from the UPS
• Switch off mains supply to UPS when PC is off
• Switch off the batteries

It's almost like you're not looking for a solution but are here merely to rant and vent.