You are right, these coolers are available in Hall-Road-Lahore..
Fan for air-cooler is same Car-Radiator-Fan... consumption around 4-5Amps on 12-Volts
Some ppl are using the Car-Vipers-Pump as a Cooler-Water-Pump... consumption around 1-Amp on 12-Volts (but its not a good one in quality and went out of order in 1 or 2 week or so... Other 12-Volts Water Pumps (around Rs.700/-) also available this year in the same market, but i have no idea about its consumption, my idea is, it will be around 1-2Amps on 12-Volts.
So total consumption of this 12-Volts-Lahorie-Type-Air-Cooler is around 5-7Amps on 12-Volts (i.e. 60-84Watts you may say well under 100Watts), you may use it directly connected with a battery or through a 12-Volts Charger/Adapter or through your UPS.
Although this is a small size Lahorie-Air-Cooler but as works continuously (cause i am using it for 18-20 hours out of 24-hours a day, through battery/ups and no load shading effects on it), its result is quite good.
if u get this thing, make is sure the fan/pump are good quality, cause there are ppl in market selling the repaired/scrap things.