Formula used: DC Current = Power / (Voltage × Efficiency). The recommended system voltage is the lowest voltage where current ≤ max allowable current. Find the ideal DC input voltage (12V, 24V, or 48V) for your inverter setup based on load power, current limits, and efficiency to ensure optimal wiring and system safety. Effective in battery sizing, cabling, and planning inverter loads. The following calculator will help you calculate the DC current (from the controller to the battery) and the AC current (from the inveter to your house).