Most solar lights are designed for specific voltage levels, typically 12V or 24V. If the voltage does not match that of the light, an incorrect battery could either underpower or overpower the system, impacting operational reliability. . To determine the appropriate voltage of battery required for a 10W solar light, several factors need to be considered, including 1. In detail, the power requirement is computed using the formula: Power (W) =. . To calculate voltage, use this simple formula: V (Volts) = P (Watts) / I (Amps) Let's say you have a 600-watt solar panel system and the current is 15 amps: V = 600W / 15A = 40V In this example, your system operates at 40 volts. Why Is This Important for Solar Power? Solar energy systems rely on. . These solar panel voltages include: Nominal Voltage. 3 How can I increase the efficiency of my solar power system? 3. (example, 2AC amps =20DC amp) Add 10% (22 amps) DC amps x 12v = DC watts. (22 x12 =264 watts) 264 would be entered in field # 3 Fields #6 and #12 are for how many hours you expect your equipment to run in a 24 hour period, and your input voltage (12, 24, 36?).