What we've found is it's immediately viable for commercial properties that make profits e.g. malls, workshops, small factories, petrol pumps, etc. The accelerated depreciation benefits mean you'll make your money back in little more than a year. If you own any such rooftop, this ought to be a no-brainer for you.
Even if you're not making profits (and so have no tax, and accelerated depreciation doesn't help you), commercial electricity rates in India are high, and you can expect break-even in about 3 years.
For residential consumers, break-even is 5-7 years, depending on which state you're in.
For your specific example, would need to know details to offer comments. At first glance, the quoted price seems way too high. Consider not installing batteries unless you absolutely must for your use-case.