Connecting a UPS to an inverter

Discussion in 'General Electronics Chat' started by goodboy, May 15, 2009.

  1. goodboy

    Thread Starter New Member

    May 15, 2009
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    I have an inverer in my house to take care of frequent power failures. Unfortunately, this inverter takes about 15-20 sec. before it deliveres full voltage.

    I would like to run my pc from this inverter so I connected a UPS in between the pc and the inverter, but this does not resolve the problem. The UPS does not come on and the pc reboots due to the power drop.

    I am now hearing that it is not possible to make this sort of commention between an inverter and a UPS but I cannot understand why.

    Could someone please help me with how I can get my pc running from the inverter without rebooting.

    Thank you and best regards
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    Assuming the inverter can handle it (and so can the PC) why not run the PC off the inverter full time, and put a charger on the battery feeding the inverter. This is basically a kludged UPS, but it might work for your application.
     
  3. goodboy

    Thread Starter New Member

    May 15, 2009
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    Thanks for the quick reply.

    My inverter only comes on when there is a power failure. Of course it would be possible for me to run a second inverter from the main batteries and run my pc permenantly off the batteries only but this would mean a major wiring job running the cales from the inverter room to the pc.

    My inverter uses 6x12v batteries in series. Do you see any problem in taking a connection from 1 of the batteries?

    Thanks again.
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    When you say inverter, do you mean UPS?

    Batteries need replaced in UPSes every few years, and you need to exchange them in pairs.
     
  5. goodboy

    Thread Starter New Member

    May 15, 2009
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    By inverter I mean that it takes some time before I get full working voltage.

    By UPS I mean when the vorking voltage in a very short time so that a pc will not reboot.
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    An inverter converts 12VDC (usually) to AC (in the USA, 120VAC 60 Hz). This is specific to the word.

    A UPS comes in several flavors, the usual is the standbye UPS, which sounds like what you have. It outputs AC when the local power grid dies.

    When you refer to the inverter are you refering to the internals of the UPS?
     
  7. RockyBlackburn

    New Member

    Sep 11, 2006
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    I was wondering if your inverter is hooked up like a standby generator? If that is the case, and it switches from the grid to the inverter, just plug your UPS between the computer and the outlet and the UPS should take care of the brown out until the inverter kicks in. Maybe I'm just on a wild goose chase here, but to me, that sounds like it might be close to your inverter setup.

    If I'm wrong about your setup, try going into a little more detail about how the inverter is set up.
     
  8. goodboy

    Thread Starter New Member

    May 15, 2009
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    RockyBlackburn, you are right about my setup and this is what I did in the first place. My problem is that, connected this way, the UPS does not come on in case of a power failure. The inverter comes on after some seconds but in this time my pc has rebooted.
     
  9. RockyBlackburn

    New Member

    Sep 11, 2006
    7
    1
    It could be that your UPS is not working or cannot handle the load of the computer. The switch from line power to the "UPS's" battery should be almost instantaneous. I just replaced the battery in my UPS that has not been used for quit a wile. Plugged my computer and monitor in and pulled the UPS's cord from the wall to test. The UPS beeped and the computer lost power. I thought it was dead and tried testing it. Plugged in a drill, turned on the drill and unplugged UPS. Drill ran for at least 5 min. before I gave up and figured the UPS is working.

    Sorry for the long story, but it seems that between the time I got my UPS and now, (a couple of computers, a few MB's and processors ago) my power consumption has probably tripled.

    You might want to try plugging in a lamp or something like that and see if the UPS works at all. Note: on mine, the load has to be active when the plug is removed from wall (power failure) or voltage drops to 0 from UPS.

    If you try this, keep in mind that some UPS's may drop some voltage when on battery, so the light may dim "a little" but should not go out or flicker.

    I still use my UPS because I like to put my computer to sleep instead of turning it off. Works fine for that application (no monitor, fans, HDD's and such). I know how you feel when it comes to "bad power" and like the idea of having a backup inverter. Speaking of which, I hear thunder and have got's to go.:eek:

    Hope this steers you in the right direction.
     
  10. rvh002@gmail.com

    Active Member

    May 15, 2009
    118
    2
    Hi there, It sounds like you have a combination of problems (like having multiple adaptors plugged into one another and all plugged into one outlet) I suggest that you get yourself a proper online double conversion UPS, rated to take your load, connect your existing stanby batteries to it (either in parallel or series depending on the Ups you get) Get rid of your invertor and other equipment (the wiring becomes totally problematic eventually) and use one machine to do the job.
    A double conversion UPS is a machine that takes the input power, charges a battery system and uses the battery system to generate the output power . It is always on line as long as the batteries can handle your load. Ie: there is no connection time involved in case of brown outs or power failures. A large part of the cost of this system is the price of the batteries. So if you talk to the supplier of the UPS, you can use your existing batteries. They can supply a unit running off 12, 24, 48 or just about any multiple of 12 voltage. I do not know what size your batteries are, but as a guide, a 102Amp/hr battery will power a 1kVA pc for about 50mins. (no extras, printers, extra drives etc)
    Hope this helps
     
  11. goodboy

    Thread Starter New Member

    May 15, 2009
    5
    0
    Thanks everybody. I finally went out and bought a new UPS, one that was rated to work with an inverter, and the problem is resolved.
     
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