UPS/Inverter

Not if you intend to feed back into the grid. But a UPS may also have a narrower input voltage tolerance than an inverter used in solar arrays as well, so it would respond by shutting down earlier and staying off longer. That results in you not getting the full benefit of the expensive solar system you just installed.

A UPS has a rectifier, unless your system is generating AC voltage, this would have to be bypassed...A UPS also contains an inverter and batteries for backup power, though most don't last very long...so you could with some modification but it wouldn't work very good, unless you had a big one...

UPS schematic diagram...

As others have implied but not stated, it is possible to use a UPS instead of a solar inverter. However, to do this there will be limitations one must expect and modifications that must be done. Depending on the capabilities of the UPS and the skills of the re-designer, the UPS may become equivalent to a proper solar inverter. The modifications will cost considerably more than purchasing a proper solar inverter.

Since you do not know all of this already, you are not qualified to do these modifications.

Thanks Dear i have 1000 watt PV power off grid system but my inverter create a problem with tube light and my computer. When i use my ups instead of inverter they work properly, so that`s why i ask a this Q, now tell me i continue use of UPS or change the inverter. 2- what will be the other disadvantages use of UPS (efficiency, losses etc)

You don't indicate what the problem is, but why not just use both the inverter and the UPS?

However, if the inverter you are using is a cheap square-wave inverter rather than a cheap sine wave or true sine wave inverter then yes your computer and lights may flicker or possibly even be damaged! I have blown up a square wave inverter just by connecting it to a fluorescent light, those square wave inverters are only really designed for resistive loads like heaters, NOT sensitive electronic loads like computers.

If you have a square wave inverter then that is your problem and it needs to be replaced with a better inverter, also connecting a square wave inverter to a UPS (as I have mentioned above) is NOT recommended as it may damage or destroy the inverter, UPS or both.

Undoubtedly this is the problem, you must use a pure sine-wave inverter for electronics, and most everything else...Wiki gives the full rundown...

http://en.wikipedia.org/wiki/Inverter_(electrical)