Solar panels. please help me and give me a serous answer.?

1

Because of the high ambient temperature where you live, and the fact that the sun shines on the panels at a slant in the morning and afternoon, you will not get 12 hours of peak sun. More likely you get 6 hours equivalent of peak sun, at the most. It might be 5.

Assuming 6 hours, you will be getting 0.3 x 6 = 1.8 kWh of power per day, let's call it 1.2 kWh after accounting for inefficiency of charging batteries. Dividing by 24 hours, that's 50 watts, so enough to run your fan, assuming you run NOTHING else (no lights, phone charger, or whatever).

If you have a deep cycle battery bank, you can only discharge to 50% capacity before ruining the batteries, which means a 2.4 kWh bank. That's 200 amp-hours at 12 volts. Or if you're using ordinary car batteries, you should have about 400-500 amp-hours worth, because those cannot be drawn down as far without damage.

They only get anywhere near 150 watts in very bright sun, not for all 12 hours, not even close. You will probably need 5 solar panels, maybe 4 in the summer. The battery needs at least 30 watt * 24 hours / 12 volts = 12 amp hours. So a typical car battery can work. But at least 2 batteries or more, or 120 amp hours or more, is better in case of cloudy days and because batteries last longer if you don't push them to their limits.

A typical 30 watt fan will start turning with 100 watts input, but it could need 300 watts to start if the bearings are in poor condition. A 100 amp hour 12 volt, deep cycle, battery can easily supply 300 watts when it is new. The fan needs about 2.5 amps running, so it uses about 60 amp hours in 24 hours, so there is a slight possibility of battery damage if you have a day which is cloudy all day. Two 6 volt batteries in series rated 200 amp hours, or more is likely a good investment as the battery will likely give good service for several years, even if you have two cloudy days in a row, occasionally. Possibly a 250 amp hour 12 volt battery is available at less cost, but it will weigh about 100 kilograms.
If you chose a smaller battery you can use a 13 volt power cube to supplement the solar panels, in December when you have less hours of sun light. Even one extra amp is likely to save your battery from damage due to excessive discharge. You are taking 2.5 amps from your battery, and solar cells, so you have taken about 100 amp hours in 40 hours, so the battery has only about 80% of the amp hours the solar panel put in during the 40 hours, which could be none in some 40 hour periods. Possibly your fan will use as much as 40 watts if the blades and grill are dirty, and/ or the bearings in poor condition. The 200 watt rating of your solar panels is for brightest possible Sun light, with the panels exactly facing the sun, so an average of 40 watts supplied by the two solar panels is likely optimistic for December, especially if you live in Northern Packistan. Possibly you expect to turn off the fan at night, November though January?

The total duration of sunlight is irrelevant. As your solar panels are only going to face to the south, Give or take. We also have 12 hours of sunlight here, In the us, However when the Sun rises in the east until at least 10 or 1030 in the morning, Solar panels have very little output. And about 230 3 o'clock in the afternoon as the Sun sets West it moves past your focus point....
Solar panels facing relatively south, And up, ..To catch that peak intensity high noon so to say...

Meaning to get 12 hours of 12 solar panels....

Point two east. two SE, four south and up, two sw, and two west.

Then your trickle charging your battery bank for 12 hours at best. To run a fan continuously nonstop 24 hrs a day would require alot of battery backup. One time I ever I did make a self-perpetuating Power plant. Involving a large PVC tube filled with water. Gravity makes the water naturally flow out to the bottom.as the water flows down it turnsthe alternators. running a pump. Squirting itback up