I could not find Su-Kam SineUPS listed here, so I’m writing under Su-Kam Brainy.
I bought the SineUPS 800VA a month back. I checked the backup time for only my CPU (without the monitor). My CPU ran for 2 hours, after which the UPS started beeping rapidly. Assuming that my CPU consumes half the power of a PC, it should power both CPU and monitor for 1 hour, which is the same a comparable 800VA UPS would give.
It’s rare to find companies that make sine wave inverters in the 800VA category. It’s pricy though, at around Rs. 4000. I know of one 800VA UPS that sells for Rs. 2300.
Guarantee period is two years on the UPS and one year on the battery. There is another UPS manufacturer which gives two years warranty for the battery.
Voltage regulation (as per the instruction manual) is around 200-250 volts, which I feel is high. Other UPSes regulate voltage at 221-239 volts.
The manual does not mention some facts. What sort of sine wave, pure or quasi? No mention of MOSFET technology. Probably this model doesn’t have that.
REVIEW UPDATE (April 23, 2006)
I want to clarify something. The electricity which comes from your mains (i.e., the electricity board) is always sine wave. Your electricity board would never provide square waves. So if there is no power failure, then the UPS simply passes on the power from the mains to your PC. Only when there is a power failure and the UPS powers your PC from the battery, then the question of sine versus square wave comes into the picture.
I tried another test. I ran a table fan from a square wave UPS and switched off the mains and let it run on battery mode. The fan emitted a humming sound (sounded like krrr-krrr-krrr). Sparks flew from the fan swiches, it also emitted a burning smell. Switches 1 and 2 of the fan stopped working, only speed 3 remained functional.
I ran the same fan on Su-Kam SineUPS on battery mode (mains switched off). The fan worked perfectly for many minutes, without any hum, no sparks, no burning.
Obviously the quality of electricity provided by the Su-Kam SineUPS (on battery mode) is superior.
I feel if you are going to run appliances like fans from your UPS, then Su-Kam SineUPS is a good choice.
However, I feel PCs and monitors work perfectly on square wave (at least my PC does), and if you have infrequent power failures, then it doesn’t matter whether the UPS is sine or square.