You need around 200-300 watts of solar panels to charge most of the 12V lead-acid batteries from 50% depth of discharge in 6 peak sun hours with an MPPT charge controller. If you are using an DC to AC power inverter, meaning your device is rated in AC amps and 110 V, you will need to convert that number into DC watts before entering it in the field. Then you will need to add about 10% due to the inefficiency of the power inverter. Start with Your Real Usage (Not a Guess) List out your actual appliances—fridge, lights, fans, chargers. Using a solar charge controller is crucial. Simply enter the battery specifications, including Ah, volts, and battery type. Also the charge controller type and desired charge time in peak sun hours into our calculator to get. Choosing the correct size solar panel to charge a 12V battery is crucial for maintaining an efficient and reliable solar power system.