Tech / Special Interest → Electronics > Looking for a desktop power backup

Re: Looking for a desktop power backup

One thing that could be better about the new "Smart UPS" line is that the charge rate on the batteries is aggressive, and the batteries only last 3.5 years now. The older RM1200 that I used to have would go 7 years on a set of batteries and it ran cool. I have a 3000 VA Smart UPS now, but every 3.5 years, like clockwork, the batteries fail. And they run hot. Would love to lower the charge current to make it run cooler and get the battery life I enjoyed with my RM1200 years ago.

Thanks, ok then it should not be an issue in your UPS, the current through those resistors will be 1/4 of what it is on the 48volt model.

Likely is, but getting the info is another story. I don't know what it is about the UPS industry, but I haven't found any of them that are willing to give any info on their units. I did get schematics from one company a while back, but I had to sign a NDA to get it.

They sent a replacement for the first unit, and ignored my inquiries about the second. Then never sent any info on how to return the defective first unit. I sort of gave up after that..

If yours is a 48V DC unit (battery voltage) then this will apply to you.

Standard warnings about playing with electricity, you don't want to work on one of these things plugged in, or with the batteries attached, and there are exposed parts (namely the cooling fins for power transistors) which are live even after line and batter power is removed thanks to some very large capacitors.

Next time you have it apart have a look at the PCB board reversion (I think yours will be "K") and look for R38 and R43, you may find them looking a tad cooked. The issue is that due to an oversight more current is pushed through them then what they are rated for, the fix is to replace them with the same value using a higher power resistor (2 W or better). You will have to mod the new resistors to fit, the pads and holes on the board are design for 1/4 resistors.

Not sure if it will fix your issue, there could be other problems which are causing your UPS to act funny.

IMHO I like APC's Smart-UPS line up because they (read the specs because I think they have a few models that don't) output a pure sine wave, just like what comes out of the wall socket. Granted with a good PSU that isn't being taxed (one that is over-sized for the build) probably would not mind a unit that did step-sine output such as there Back-UPS pro line up which you will find are less expensive.

Here is a link to a guy that took the time to graph the output of both types of UPS's: »www.repeater-builder.com/backup-···est.html ( thanks to WA1MIK for doing this test! )

As you can see a the stepped type UPS output sits at zero volts for a sizable amount of time, this means those that capacitors inside the first stage of your PSU to drain down a bit farther when operating on battery mode which could stress things more.

Read the specs, most of the stuff is listed in volt amps (VA) which is not the same as Watts (W), they are not the same thing. A good UPS should last for years, or several computer systems.

Does APC have a fix for this issue?

Could be that the quality has fallen off there recently. I know that my APC SmartUPS 1500 is 8 years old and has never failed (except for needing the batteries replaced a few times).

I'm not so sure about the APC's anymore. I don't know if it was just my luck or what, but I ordered 5 APC 1500's a year ago and so far 4 of 5 have failed with a stuck transfer relay code. A real PITA when you have to drive to a site to reset the thing that was supposed to have prevented the power glitch but instead created it.

Given those specs I'd say any UPS rated for 350 watts or more should do the trick.

Add a bit to allow for future expansion.

I'd go with something like this (420W):

»www.apc.com/products/resource/in···atts=350

Or this (600W):

»www.apc.com/products/resource/in···atts=350

Post disappeared or glitched so i'm going to repeat most of what i said..

VE198/ASUS monitor (LED)
C2D E6550
EVGA NVIDIA 550Ti
3 HDD's

Hopefully this is enough, have no idea what happen to my last post.

Power supply capacity does not give a good indication of how much power your computer actually needs.

You're going to need to measure the power consumption using a device such as the Kill-A-Watt meter, or provide specifics on the computer hardware.

-manufacturer/model of monitor
-processor
-video card?
-number of hard drives?

Most desktop computers except really cheap pre-builds don't even come close to using the power supply's full rated capacity.

I have a gaming rig so i'm gonna need somethin a little more powerful than a small ordinary battery backup. My power supply size is 600W and monitor is just a 20 inch LED

Needing something that will get me just to make a shutdown so there will be no OS shutdown failures. I have been receiving quite a lot of power outages lately and in-need of a battery backup. Anyone have any ideas? Anything at all?(:
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