You need to determine the wattage of each device and they need to add up to be lower than 800 watts.
Depends on the wattage of the cooler. 800 watts would be a small cooler I think. You need to check the cooler specification before connecting it to the inverter.
yes/no
No. The 12volts will not make a difference. The inverter converts the 12volts to 110/115volts. A 400watt inverter is not sufficient to run a power saw or any heavy power equipment like that. Laptops consume 20-50watts, while a coffee pot would consume more like 200-400watts. Your power equipment is a much heavier load, between 1000-4000watts depending on if it is a power saw or something larger. A basic 7 1/4 circular saw will use anywhere from 1000-2500 watts on starting and will draw a constant 800-1500 watts. Keep in mind it will draw more as you put it under load of cutting something, this will not run on a 400 watt inverter, let alone an 800 or 1000watt. You could however possibly run a power drill on that inverter, but otherwise no luck.
Normally speaking, a 3500 watt generator can typically power appliances such as refrigerator (500-800 watts), laptop (50-100 watts), television (100-400 watts), stereo system (200-400 watts), air conditioner (1,000-2,000 watts), electric stove (1,000-2,500 watts), lights (50-100 watts). It's important to check the specific power requirements of your appliances as they can vary.
800 milliwatts, or 0.8 watt. It's a measurement of output power or power consumption.
800 watt should be fine
2248 watt power
You can power any amount of devices that total to a sum of 800 watts. If you can not find the wattage on the devices nameplates then use the amperage of the devices. I = W/E, Amps = Watts/Volts. 800/120 = 6.6 amps. A total of 6.6 amps can be used from a 800 watt generator.
1200 Watt wiring is more than enough for an 800 Watt amp. The rating of the sub doesn't make any difference to the cables. If you want to use the sub to its rated power you should get a bigger amp. If the amp can only give out 800 Watts and the sub can take 1100 Watts then you can put a bigger amp on. It is still going to be loud as with an 800 Watt amp. I have a 300 watt amp with a 1200 Watt sub and people hear me coming.
Need to know the voltage. I = W/V.
You need a 800 watt PSU or above as that will provide you enough power to run it and will even leave a scope for upgrading in future. Get 1000 watt if you can and be happy for forever. Corsairs are good. Its a decent build you have.
Energy = power X time. 800W X 120sec = 96000J