The Battery Voltage (V) is the the volts your battery is...ex 12v, 24, 48v.
The Battery Capacity (Ah) is the Amp hours the battery is rated for...ex 10Ah, 20Ah, 30Ah, 50Ah, 100Ah, 200Ah.
The Device Power (Watts) is what the device is rated for and gives you how many hours and/or minutes the battery can power the device based on the device's power consumption...ex a typical cell phones use 10W of power so, if you have 2 cell phones, it would be 20W of power.
(This is where you need to calculate how many devices and how much watts you will be using.)
Battery Capacity (Ah):
Enter the capacity of your battery in amp-hours (Ah). This is the total amount of energy your battery can store. For example, a 100Ah battery can store 100 amp-hours of energy.
Battery Voltage (V):
Enter the voltage of your battery. Common values are 12V for small solar systems. For example, a 12V battery will typically operate at 12 volts.
Solar Panel Wattage (W):
Enter the wattage rating of your solar panel. This is the maximum amount of power the panel can produce under optimal sunlight conditions. For example, a 100W panel can produce 100 watts of power under full sun.
Average Sunlight Hours per Day:
Enter the average number of hours per day your location receives full sunlight. For example, if you receive 5 hours of good sunlight each day, enter 5. This can vary depending on your location and the time of year.
System Efficiency:
Enter the efficiency of your solar panel system as a decimal value between 0 and 1. The default is 0.75 (75%). This accounts for system losses due to factors like wiring, inverters, and other components that reduce the total energy transfer.