Please note that the unit of electrical power is kilowatt/hour, which is the capacity or amount of electricity that can be produced in one hour. On a solar panel, 100 watts means producing 0.1 kilowatts of electricity in one hour. , or 0.1 kilowatt-hour of electricity in one hour. 100W solar panel power actually means the maximum output power. Generally it does not reach 100 watts. If it's in high latitudes at 5 p.m., it may only be 10W. If your battery is 12V, its maximum instantaneous current is 8.5A, which is quite large. Let me teach you how to determine the actual power generation capacity of solar panels. When the equatorial sun is directly irradiated, the energy projection per square meter converted into 100% electricity will not exceed 1,000 watts, and the conversion efficiency of our civil grade solar energy ist usually 10%, which means the panel per square meter will not exceed 100 watts of power, you can ask the store owner how many square meters his battery is to find out if he is cheating you. The need for an inverter depends on the power of the electrical appliances you use. For example, if you turn on a 1000W lamp, in theory a 1000W inverter is enough. Of course, the real need is greater. But your 100W solar cell needs to produce electricity at full capacity for 10 hours to turn on your lights for one hour.
Theoretically speaking, according to the duration of sunshine in the north, 6 hours of exposure from 9 a.m. to 3 p.m., the current is about 5A, 13V*5A=65W, the power of 6 hours is 65*6 = 390 W, and the kilowatt hour is 0.39 degrees of electricity. There will be fewer in winter and more in summer when sunlight hours are longer. But the actual current will vary from 3A to 5A perday. The current is 2A in the morning and evening, and the probability is 0.3 degrees in winter and 0.4 degrees in summer.