Well as per my research portable ACs will all use at least 1200 watts of power (for 1 ton). I don't think 150 watts is realistic as even ceiling fans use more these days.
Yes brother I considered solar option but trouble is it won't work at night without a big battery bank and as you know batteries for UPS only last 1-2 years so I don't want to deal with constant headache of replacing them.
Yes you are right that a 'juggady' system like this will most likely not be reliable in long run....
Still searching for right solution...