I am using Su-Kam Falcon for one year. and this is the best sine wave inverter in India. APC is also a good brand in India so I am comparing it with APC....
PROS:....
1) I done some research about lead acid battery & charging. and I found Su-kam is best in battery charging. when charging no acid boiling sound and when charge is completed the battery is cool like unused battery. in battery charging Su-Kam is far batter than APC. because my friend have APC and the battery was worst heated when charging....
2) I am using "Exide IN 1500 PLUS" this is best maintenance free battery from Exide not VRLA. I am using this battery for one year. Still I need not watter topping because water level still in higher than minimum level. but my friend have same battery with APC inverter and he need to water topping every month and battery charging capacity worst decrease in one year. so Su-Kam have more perfect charging technology than APC....
3) Su-Kam falcon is very efficient when charging and when running. so the inverter is not heating like APC. and runtime on battery is very good. I have not tested maximum run time but I run it for 4 hour with 2tubelight+2fan+4cfl+1computer and still battery not fully discharged. APC run for only 3 hour with this load and same battery....
4) it give clean Sinewave and fixed voltage at any load. APC voltage change by load....
5) my Su-Kam falcon is running for one year and no malfunction and any problems. APC also have not any problems....
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CONS:....
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1) the quality is not look good like APC....
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2) its change over time is longer than APC in inverter mode. and when it in UPS mode change over time is same to APC. but worst noise come out when it go power to battery in UPS mode but only noise not any problems....
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3) Falcon i2 is not available in kolkata. so I bought Falcon and it have not battery & load level indicator like i2....
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never buy su-kam battery. just go for Exide battery and Su-Kam SineWave invarter.