Ups Battery Backup

[WeaponX 0]

I'm currently using a regular power surge protector for my computers. I have been thinking of buying a UPS battery backup instead. Is there any big advantage over having a regular surge protector? I mean, if I do get a surge, will the UPS backup still be in good condition for me to shut my computer down properly?Most of the lower end UPS backups I've seen say the power run time is 4-10 minutes long. Why does it take 4-8 hours to charge it up to 90% and give so little power usage at the end? What should I look for in terms of joules, VA, and other terms I see being used?Very new to the UPS backup devices, so any help will be greatly appreciated. I will be using my computer, monitor and maybe an external hard drive for this. So one with 4 ports or so will be perfect. Also, any brands in particular that you like?Thanks.

[unimatrix 0]

4 - 10 minutes is enough to shut everything down and is very handy if you are on a desktop and in the middle of a project. You can at least save and exit before loosing total power. And it takes so long to charge up because it trickle charges while most of the power is used to run whatever is attached. I use a laptop anymore, so if the power goes out, I still got 3 hours of work time. Still, if your on a desktop, not a bad thing to have.

[faulty.lee 0]

I'm currently using a regular power surge protector for my computers. I have been thinking of buying a UPS battery backup instead. Is there any big advantage over having a regular surge protector? I mean, if I do get a surge, will the UPS backup still be in good condition for me to shut my computer down properly?

I need to clarify a bit on this. A surge actually means a sudden change in voltage or a spike in the power supply, including lighting strike(not a direct strike, but in cases which it affect the power supply). Usually in terms of microsecond to milisecond. Power supply here, i refer to the power transmission or simply the power socket. So, for this, you'll need a surge protector. A surge protector generally only protect when the voltage goes higher than expected, cause that is more damaging. With most PC and monitor using switching power supply(in the equipment) , it can handle various voltage fluctuation from 90 to 240 volt, as long as it's within 240, maximum. Some PC power supply can only handle +/- 30 volt of fluctuation, from the set point.
To counter voltage fluctuation, you'll need a voltage stabilizer. It regulate the voltage to within the expected voltage, to reduce damage or unexpected behavior from the equipment.

Where as UPS, is to provide power when there's a blackout, or when the supply is below an unusable voltage. Nowadays, most UPS comes inclusive of surge protector and voltage stabilizer. If your area always have lightning strike, then it's better to get a separate surge protector, cause lightning surge is not covered by warranty, so it's better to change the surge protector rather than a new UPS, which is few times or even up to 10 times the price.

Most of the lower end UPS backups I've seen say the power run time is 4-10 minutes long. Why does it take 4-8 hours to charge it up to 90% and give so little power usage at the end? What should I look for in terms of joules, VA, and other terms I see being used?
Very new to the UPS backup devices, so any help will be greatly appreciated. I will be using my computer, monitor and maybe an external hard drive for this. So one with 4 ports or so will be perfect. Also, any brands in particular that you like?

I've use PK long time ago, which is very good. If i were to buy another one. I'll go for PK.

The length of time you can operate, it's dependent on the battery inside. The capacity is specified by Ah(Ampere hour). The maximum power of which the UPS can supply is Watt or VA(Voltage Ampere). Watt = VA in terms of calculation.

Say you have a PC which is 300Watt, and a monitor of 150Watt. So your total power requirement is 450Watt. a 500Watt(VA) UPS will do. If your power requirement is more than that, the overload LED will lit up on the UPS.

Now come to the on time. For a normal UPS, the battery is usually seal lead acid type, with about 12V 7Ah. With 7Ah, meaning you can drain 7A for 1 hour, or drain 1A for 7 hours. So, with 450W, and a supply voltage of 240V. You'll need to workout the current drain at the battery.

Supply = 240V
Power = 450W
Battery = 12V
Battery's current = 450W / 12V = 37.5A (Assuming 100% efficiency)
At 37.5A, 7Ah will give out
On Time = 7Ah/37.5A = 0.1867Hour = 11 Minute 12 Second
With 80% efficiency, you get around 9Minutes

And also keep in mind that the battery degrades over time, so the On Time is getting shorter and shorter. So it's safer to shutdown within 4 Minute.

As for charging, it's not safe to charge at that high of the current. Usually charging is recommended at C/10, at most C/1. C is the Ah. So maximum charging current is 7A in this case, and it will takes 1 hour to fully charge, again assuming 100% efficiency. It it's charge at C/10, 0.7A, then it will takes 10 hours to fully charge the battery. After full charge, trickle charge is applied to maintain the battery to full capacity, and to over come self discharge. You want your UPS to be ready 24/7.

If you want longer On Time. Look for bigger one with higher Ah. Some for cooperate use type, can be connected to car battery. The smallest car battery is 50Ah, which in the above scenario it'll have 1 Hour 20 Minute of On Time. But it will need a day or 2 to fully charge it. Or you can bring it to some car workshop to have it charge. Here it's only 2 dollar. Most hawker do that, can use the battery to power lights and fan at night at the stall.

One thing to take note, don't power any inductive loads with the UPS, this includes motor and solenoid driven equipment. Like fan, drill, electric stapler, fluorescent lamp(yes, it has an inductor in it) and so on. The AC supply produce by UPS is not 100% sine wave as per those produce by the power station, so it will have unexpected result, or even damaging effect when use on inductive loads. You'll see that the same rules applies to electronic dimmer.

Hope that's enough of info. Anything else just let me know, I'll try my best to explain.

Regards

[.:Brian:. 0]

I use a UPS and it is a very nice thing to have. Especially since my power will frequently flicker....which causes it to just go out for a second or so, just long enough to cause the computer to restart....which is a pain....especially if you lose work...So I just have one of the ones where it can provide like 15-20 minutes of power (supposably)...However, I don't have anything for the monitor...so when the power goes out, my computer stays running, but my monitor goes off...but that is what the autoshutdown functionality is for, so that it shuts down either when there is x ammount of battery remaining or it has been running on the batter for x ammount of time.Anyhow, I do recommend that you get a UPS as they do a great job at protecting your computer. Just keep in mind that you'll probably have to replace the battery every 5 or so years (you can easily get along longer, it all depends)

[WeaponX 0]

Thanks faulty.lee, that was very informative. Just had a question whether the UPS will use a lot of power because if I do buy it, I will leave it plugged in 24 hours (as it should be used ). If it's only charging the battery a trickle at a time, won't that degrade the life of the battery even more? I thought, like most other batteries, that you shouldn't constantly charge it. Sometimes you should fully discharge and then do a full charge to get more life usage out of it.The area I'm in seems to be pretty good. I never (hopefully won't ever) had the power go out on me. I might stick with purchasing another surge protector in that case if it won't damage my equipment. I save frequently so don't mind being knocked off if "disaster" does strike :PBrian, why don't you have a surge protector or UPS for your monitor? They have multiple outlets and I try to use whatever electronics I have on them since they are convenient and also I don't have a lot of outlets in the room

[jimmy89 0]

Brian, why don't you have a surge protector or UPS for your monitor? They have multiple outlets and I try to use whatever electronics I have on them since they are convenient and also I don't have a lot of outlets in the room

Brians idea is good! the less that he has plugged into the UPS means the less drain it has on the UPS - and as faulty.lee said - the battery will last longer with less items to run. This also means that you wont need as much watts, which means you dont need to by a UPS with heaps of watts.

Most UPS's will come with software that will safely shutdown or hibernate (and save work) your computer when the power goes out. This means that If the monitor doesn't have power it wont matter - the computer will shutdown and you'll be safe!

In my case, I would need to have the Computer as well as my External HD plugged into the UPS. Those together would be a bit of a drain on the battery!
Edited June 23, 2007 by Jimmy89 (see edit history)

[faulty.lee 0]

Thanks faulty.lee, that was very informative. Just had a question whether the UPS will use a lot of power because if I do buy it, I will leave it plugged in 24 hours (as it should be used ). If it's only charging the battery a trickle at a time, won't that degrade the life of the battery even more? I thought, like most other batteries, that you shouldn't constantly charge it. Sometimes you should fully discharge and then do a full charge to get more life usage out of it.

Yes, trickle charge will degrades the battery over time. But you need your UPS to be ready 24/7. What if the blackout happen when your battery only have 25% of it's power, that mean you only have 1 to 2 min to save your files and shutdown. If you're at a middle of editing a huge file or project, it will take longer than that to save and close the app. Even if you have save the file, the OS might still store the lastest changes in the ram, queuing to flush the cache. Blackout that happen when the OS is writting to the harddisk can corrupt the file, it happened to my customerS, which it ended up very costly, well, it's a good chance to persuade them to buy an UPS.

Jimmy89, those UPS that comes with software control are quite expensive, generally it's mend for cooperates customers. Actually it's not the software that does the work. The UPS simply has an serial(COM) or USB port, which you can plug into your PC. Windows will recognize it and even show the battery level. From there, you can configure what to do in the event of power blackout, more or less like those we see on laptops. A good thing to have actually, if you can afford it. Cause it might blackout when you went for a tea or something.

[WeaponX 0]

I thought that the backup battery on UPS will last more than 4-10 minutes. I guess that's only for the more expensive types. I see exactly what you mean now. I usually save frequently and guess I don't really need the backup battery. I just overlooked the differences between a regular surge protected and the UPS battery backup. Going with the surge protector <_<I have looked at a few of the UPS and see that they all come with some kind of program to monitor the power. The ones I looked at are Ultra branded UPS'

[Grafitti 0]

I don't know if you can buy both types over there, but here they sell dry-cell and wet-cell UPS models. I have some dry cell ones, a local brand, so already they're not that good, and when new they hold a charge of @ 8 minutes when i had a 300w PSU and 17 inch monitor. The same UPS will last up to 20 min if you have a 15 inch monitor, and with my 21 inch, it lasts barely a minute and a half. Here i'm talking CRT monitors, if they were LCD they'd use alot less power. Within a year, though, the batteries have degraded to the point that they take like 6 hours to charge, and only give me 5 minutes of backup, plus they occasionally don't kick in when there's a drop in current, and the computer reboots.... Never mind what i paid for them back then, but today the street price for them (550w) is around $50. If i were to double that price, i can get branded UPS with wet cell batteries, which will last up to 2 hours with a 15 incher, and around 1 hr 15 min with a 17 inch. Have a friend who got one, and he's happy with the performance.

[faulty.lee 0]

I don't know if you can buy both types over there, but here they sell dry-cell and wet-cell UPS models. I have some dry cell ones, a local brand, so already they're not that good, and when new they hold a charge of @ 8 minutes when i had a 300w PSU and 17 inch monitor. The same UPS will last up to 20 min if you have a 15 inch monitor, and with my 21 inch, it lasts barely a minute and a half. Here i'm talking CRT monitors, if they were LCD they'd use alot less power. Within a year, though, the batteries have degraded to the point that they take like 6 hours to charge, and only give me 5 minutes of backup, plus they occasionally don't kick in when there's a drop in current, and the computer reboots.... Never mind what i paid for them back then, but today the street price for them (550w) is around $50. If i were to double that price, i can get branded UPS with wet cell batteries, which will last up to 2 hours with a 15 incher, and around 1 hr 15 min with a 17 inch. Have a friend who got one, and he's happy with the performance.

The wet cell is actually lead acid battery, aka car battery. They hold plenty of AH, so it can last a very long time. They're also more expensive. Normally bank or cooperates use it. Dry cell is sealed lead acid, they're not actually dry, it's just that they use gel instead of liquid electrolyte. The life span is only about a year or 2. You can just open up the UPS and replace the battery. You can get one in electrical shop easily. Not those that sell consumer electronics, go to those that sell lamp, switches or alarm. They normally use this battery for emergency lamp, home alarm backup and so on. Here, i can get it around RM30 to 70 a piece, bout $10~$20.

[.:Brian:. 0]

As to why I don't plug my monitor into it...it is because I want to maximize the battery life...and my monitor also appears to be a big power hog...when I turn it on it causes the lights to dim as it turns on....and sometimes enough to where the ups activates...and if it is plugged into the ups...sometimes when i turn the monitor on, it'll cause it to overload and shut itself off which isn't very good.The nice thing about the UPS I have is that it has 3 outlets that have the battery backup, and then 3 outlets with just surge protection.Also, it is nice to have a phone plugged into my UPS...so when the power does go out, especially if it is storming, i can use a cordless phone (no risk of getting shocked because of a lightening strike) even when the power is out.

[faulty.lee 0]

As to why I don't plug my monitor into it...it is because I want to maximize the battery life...and my monitor also appears to be a big power hog...when I turn it on it causes the lights to dim as it turns on....and sometimes enough to where the ups activates...and if it is plugged into the ups...sometimes when i turn the monitor on, it'll cause it to overload and shut itself off which isn't very good.

That's usually because of the degauss circuit, which kick in when the monitor first power up. Degaussing is to remove magnetic field that stuck to the metal mesh in the tube, which will cause some funny coloring to appear on the screen if not done. Degaussing require quite a huge amount of current for a very short while, so UPS will treat that as overload. Some newer monitor will continue to provide degaussing even after a long usage, and when you turn it off and on again, that you can't use on the UPS. Older model which depend on the PTC resistor, will not be able to degauss a second time without cooling down. If that's the one, you can use it on the UPS, unless you keep your monitor off most of the time.