Computers & Electronics

How Does An APC Battery Backup Work?

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  • Feb 11th, 2018 11:07 pm
[OP]
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How Does An APC Battery Backup Work?

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Provides hours of power through a power outage, no surges to your products.

How does it accomplish this? Is it consuming a high level of electricity, running up my bill, so that it saves this 2 hour battery pack for when the power goes out?

I'm wondering if it's worth having around for a home computer basically, when I have a concern about the bill. Thanks
Last edited by Mars2012 on Feb 7th, 2018 12:59 am, edited 1 time in total.
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DaVibe wrote: Provides hours of power through a power outage, no surges to your products.

How does it accomplish this? Is it consuming a high level of electricity, running up my bill, so that it saves this 2 hour battery pack for when the power goes out?
It has a battery inside the device... it uses a little electricity to maintain the battery, but not a lot.

Also, UPS runtime isn't 2 hour - if you plug in a desktop into this battery, it may power it for 5 minutes or so.
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East Gwillimbury
The unit you linked is 650 VA rated at 350 Watts. It takes 10 hours to charge according to the specs. Your wall receptacle is capable of outputting 1500 - 1800 Watts. This means that the UPS only charges at a rate of ~35 Watts per hour.

To put this in perspective, it would cost 2.86 cents per hour (assuming an average of 10 cents per kilowatt) to charge it from empty.

The rate of discharge would be a lot less and your cost to top it up would be fractions of a penny.

The math is very rough, but you probably have lights that use more electricity than this UPS would.
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The parasitic losses for keeping the UPS battery topped up is nothing in the grand scheme of things. It is probably comparable to keeping the clock on the stove running. These days with so much dependent on an internet connection, losing it to a power outage is a big deal. I have several UPSs at home to keep critical equipment like the modem, router, wireless home phone running through short power interruptions that don't last into the multiple hours. I also have my desktop connected to a UPS. It is set to power down within 2 minutes of an extended power interruption. It is important for graceful shutdowns.
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I know someone who had a power outage that fried his TV, and fried the SSD inside his PC (yup, not the PC, just the SSD in it, what the heck?)

Got him hooked up with 2 750VA units, one for each device (new TV, new SSD) and he's rockin' now.
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Poutsounia wrote: I know someone who had a power outage that fried his TV, and fried the SSD inside his PC (yup, not the PC, just the SSD in it, what the heck?)

Got him hooked up with 2 750VA units, one for each device (new TV, new SSD) and he's rockin' now.
I got hit with a power surge during the summer about 4 years ago that fried an external drive but nothing else. The PC shut down, but was otherwise okay. The platter drives and SSD inside were completely fine. Electronics are weird, and some are a lot more sensitive than others.

OP, if you're that concerned about your bill, plug it in at the start of an off-peak billing period. It'll charge when rates are cheap, then use very little power to maintain itself.
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A UPS normally provides direct AC line power to the battery backup sockets, and just trickle-charges its battery in the background. In the event of a power failre it can switch the sockets over to battery power within a time of about 5 msec, which is usually fast enough to prevent electronics with capacitors in their power supply from glitching. Then those plugs are powered by the battery through an inverter that generates 110v AC power. Usually it's fairly rough and noisy power rather than a smooth sine wave unless you pay extra for a true sine-wave UPS, but that doesn't matter for most devices. Weakness: the battery is always being trickle-charged, and it slowly weakens until you have to replace it anyway after 2-3 years.

You pay more for a UPS that has the "no interruption" feature (zero switchover time). They accomplish that by having the sockets always powered through the battery and inverter system rather than having to switch over. The charger needs to be a high power charger to keep the batteries charged while they run at full capacity, not a trickle charger. And of course the batteries die sooner since they are in constant use.
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Gee wrote: For $72, you're not getting a sine wave UPS and you're definitely not getting an online UPS
Lol most people don't need that much UPS anyway. I'd get a high quality one for very expensive electronics, like a huge OLED TV or something. A Laptop or a non-Gaming desktop is fine with a cheapie.
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Poutsounia wrote: Lol most people don't need that much UPS anyway. I'd get a high quality one for very expensive electronics, like a huge OLED TV or something. A Laptop or a non-Gaming desktop is fine with a cheapie.
Why do you need an expensive UPS for a television? You want to watch television during a power failure?

Most surge suppressors have $10,000 insurance if it damages your electronics. A notebook doesn’t need a UPS, the battery is built in.
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Gee wrote: For $72, you're not getting a sine wave UPS and you're definitely not getting an online UPS
I somehow already have 2. Deciding whether to use them or sell them. Couple years old, never used.
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DaVibe wrote: I somehow already have 2. Deciding whether to use them or sell them. Couple years old, never used.
You should check the condition of the battery if they’re older units.
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Gee wrote: You should check the condition of the battery if they’re older units.
What would you suggest I do, to do that?
Charge them, try to run something off of them?
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DaVibe wrote: What would you suggest I do, to do that?
Charge them, try to run something off of them?
That would be the simplest test. Charge over night. Plug in something with a decent load (200 Watts) and see how long it takes to drain the battery.

If it doesn’t last more than a minute, you need new batteries.
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Oct 1, 2009
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Most likely a battery replacement is required. That would run around 20-30 bucks per battery (might be a 9ah) version. Surge protection it's pretty much for just surges which is different from failure due to a non-shutdown type of situation.
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Gee wrote: Why do you need an expensive UPS for a television? You want to watch television during a power failure?

Most surge suppressors have $10,000 insurance if it damages your electronics. A notebook doesn’t need a UPS, the battery is built in.
Power failures aren't the problem. Brownouts are. If you get dips below 80v, depending on the quality and efficiency of the power supply, the undervoltages might dip internally for the components as well, and those electronics may or may not be sensitive to that.

It's a far lesser problem than a surge, but even a surge will only be protected by a quality surge protector (not those cheapie dollar store bars). I'm taking about a surge protector that actually has a decent board with good inductors and varistors to absorb the spikes.

But if you want to be paranoid like me, if you bought a $3000 OLED, you can afford the $500 for a quality true sine wave UPS, and as a bonus I've sat here and kept on watching TV for an extra 45 mins the last blackout I had, with my speakers, and my internet all up and running.

As for Laptops you are right, undervoltage won't be a problem for most, and a surge should "hopefully" only blow your AC adapter and nothing else. But I need my laptop running for as long as I can in a black out. Hence, a 1000va UPS will probably give me about 2hr running a 15" one before running out and relying on internal battery.

Yeah I'm a freak.
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Dec 7, 2015
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The surge protection in a UPS is usually pretty minimal. If you need a surge protector, get one. If you need a UPS get one. But unless you pay a _lot_, you won't get both in one unit.
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DaVibe wrote: What would you suggest I do, to do that? Charge them, try to run something off of them?
Exactly. Life expectancy of batteries is about three years. And those technology batteries fail completely if left discharged for too many months. Defective batteries would, at best, provide power for less than a minute.

Additional background. Generally, power from batteries is only half the power that charged them. Efficiency is not found in a UPS. UPS has one purpose. Temporary and 'dirty' power so that unsaved data can be saved.

UPS claims near zero hardware protection. Anyone can read the specification number. Most do not. If it has any smaller protection, then that joule number would be zero. It only has enough joules to claim that near zero protection as 100% protection.

Brownouts and blackouts do not harm electronics. If brownouts exist, then 'at risk' appliance must have that protection. A UPS is needed on a refrigerator, furnace, vacuum cleaner, garage door opener, any fan, etc. Those are threatened by brownouts. To increase electronics life expectancy, we sometimes include an inrush current limiter. That intentionally creates a brownout to electronics - to increase life expectancy.

Blackouts do not damage any appliance. Only those who make conclusions from observation (also called junk science) recite that wild speculation. No fact or number justifies that myth. UPS is temporary and dirty power to protect what is harmed by a blackout - unsaved data. Blackouts do not harm saved data and hardware.

Output from a UPS can be some of the 'dirtiest' power inside a house. For example, this 120 volt sine wave UPS outputs 200 volt square waves with spikes of up to 270 volts. That is safe and sufficient power. Internal protection inside every computer is so robust as to make that 'dirty' power irrelevant.

Do not connect a power strip protector on that UPS output. Power that does not harm any electronics can also destroy those near zero joule protectors.

Voltage can drop so low that incandescent bulbs dim to 40% intensity. A voltage that low is fine for any properly constructed computer. How often do your bulbs dim that much? Never? Then your voltage is ideal for all computers.

Do bulbs change intensity when other appliances power cycle? If yes, then get household wiring fixed. The naive would cure symptoms by getting a UPS. The informed, instead, fix a defect. A major appliance would power on or off - and no light bulbs must change intensity. That intensity change indicates a workmanship problem (not critical), or in rare cases a major human safety threat.
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westom wrote: Do not connect a power strip protector on that UPS output. Power that does not harm any electronics can also destroy those near zero joule protectors.
USP makers tell you not to do this. However, if you do need both UPS and surge protection, do you put the surge protector between the wall and the UPS instead?
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willilumplump wrote: However, if you do need both UPS and surge protection, do you put the surge protector between the wall and the UPS instead?
Why assume a box will magically do protection? Always do what the informed do. Read specification numbers.
Power that does not harm any electronics can also destroy those near zero joule protectors.
Why even consider a near zero joule protector (or UPS) with a massive profit margin? Spend tens or 100 times less money for a best solution.

Effective hardware protection will always answer this question. Where do hundreds of thousands of joules harmlessly dissipate? Informed consumers do what has been routine in every facility that cannot have damage even 100 years ago. This effective solution has been that well understood for that long. Unfortunately too many do not know how to learn facts; are only educated by speculation, hearsay, and advertising. If those sources are honest, then numbers from them were posted here. No numbers provided. Because even manufacturer specification numbers (the only place they must be honest) were ignored.

If that TV or computer needs protection, then so do so many other and less robust appliances. What protects a dishwasher, GFCIs, door bell, furnace, dimmer switches, garage door opener, toaster, clocks, refrigerator, and the most critical item if a surge exists - every smoke detector.

That is what one 'whole house' protector does. It even protects near zero joules in a power strip protector or UPS.

Either a potentially destructive surge is inside hunting for earth ground destructively via appliance. Or do what is standard when even direct lightning strikes do not cause damage. Earth that current on a low impedance (ie less than 10 foot) hardwire connected to single point earth ground. That sentence is chock full of facts that get '*forgotten*' when one is educated by propaganda sources; not by science and numbers. Even the last four words all have electrical significance.

Where do hundreds of thousands of joules harmlessly dissipate? Your TV cable (required by code) is hardwired to earth ground. No protector required. Your telephone wire cannot connect directly to earth. So a protector, installed for free by a telco, makes that connection to earth. No protector does protection. That free and required telco protector only does what the above hardwire does better. Connect to the only item that actually does protection - earth ground.

If any (of maybe three) AC wires does not connect low impedance (ie less than 10 feet) to earth, then all protection is compromised. When a surge enters on any one wire, then it will go hunting for earth destructively via appliances. Adjacent (plug-in) protectors can even make that damage easier. Plug-in protectors (nor UPS) claim to protect from this other transient that actually causes most damage.

A UPS is temporary and 'dirty' power for blackouts. Blackouts do not damage any appliance. That anomaly has no relationship to another anomaly that requires a completely different solution: properly earthed 'whole house' protection. Because a protector is only as effective as its earth ground.

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