after sunset 1.5 ton ac running on batteries is 'Huge task'. a genuine perfect inverter 1.5 ton ac start up amp pull is under 8 amps which drops to 4 amps under ideal conditions.
a 6KW Hybrid system which is configured 'Battery charge via PV only' can reduce your energy bills upto 40 -55 % in terms of unit consumption., during peak summers. While you can use ac(s) without hitch during sun hours.
you shall look at your KE bill, multiply sanctioned load with 1.5 resultant figure is the optimum load requirement for an hybrid solution.
in order to use AC(s) after sunset and or power shut down over 2 hours you may need a BIG battery bank. So the larger the battery bank the larger PV string required to charge batteries while managing load over inverter during the day.
Grid tied systems are useless when grid is OFF, the user end up adding more panels and extra inverter requiring more investment. The cost effective savings over bill amount becomes insignificant