If we assume your battery (12V, 120Ah) is depleted down to 20% after a night of use, then you need to put 12*120*0.8 = 1152Wh back into it during the day to recharge it. If we assume a 90% charge efficiency, this is 1152/0.9 = 1280Wh to be supplied by the PV system during the day just to recharge the battery. Assuming an inverter efficiency of 95%, this is 1280/0.95 = 1347Wh = 1.35kWh from the PV modules. If we assume that the PV module is polycrystalline, and 13% efficient, then you would need 1.35/0.13 = 10.38kWh of solar radiation on the PV modules.
https://eosweb.larc.nasa.gov/cgi-bi...p=1&lat=16.519028&lon=80.621494&submit=Submit
For Vijayawada, the worst case month is July, with an average of 4.17kWh/m^2/day horizontal radiation. So, if you laid your PV modules flat, you'd need 10.38/4.17 = 2.49m^2 of PV module area. If you tilt the modules at the correct angle, you might get an extra ~10-15% solar radiation. So, 2.49/1.1 = 2.26m^2. But, there are other losses in the system (such as dust on the modules, wiring losses, MPPT losses, PV module mismatch, etc..) which may add up to ~5%. 2.26/0.95 = 2.38m^2 of PV modules.
A typical PV module (~13% efficient) might be rated for 170W, and 1m x 1.3m = 1.3 m^2. So, you might need two of these, so 340W total.
Keep in mind, that this is JUST to re-charge the battery on an average July day. If you are also using electricity during the day while the battery is charging, then you might want to double the size of the PV array, to 680W.
Edit: I just realized its a 150Ah battery (not 120Ah), so multiply everything by 150/120 = 1.25. 680W * 1.25 = 850W. Also, if you want to be able to charge on a cloudy day you might want an even bigger system. So, your 875VA inverter sounds suitable for the application. If you tell me the model of the inverter, I can help you choose the number and type of PV modules to get.