A 6V 20W solar panel produces approximately 3. This is derived from the power formula calculated by dividing the wattage by the voltage, 3. Consequently, in milliamps, this equals 3333. Adjustments may result from efficiency losses or system design. Consequently, in milliamps, this. To determine the current output of a 6V solar panel, one needs to consider several factors like light intensity, panel specifications, load requirements, and the formula for current calculation. Determine the load resistance, 3. Use Ohm's Law to calculate current. How to use this calculator? Solar panel output: Enter the total capacity of your solar panel (Watts).