Question: how many watts does it take to charge a laptop battery?
Answer: A 1 kilowatt hour is 1 kilowatt for an hour, so a device that uses 1,000W and ran for 5 hours would need 5 kWh of power. Laptop batteries will sometimes say what their watt hour rating is. If it's rated at 150 wH, this means it can output 150 watts for an hour. Most laptop adapters are 60-90 watts.