A typical 12-volt car battery can safely support an inverter ranging from about 150 watts up to 600 watts for regular use without harming the battery. Wondering if your 12V 6W power supply can handle a 12V inverter? This guide explains compatibility challenges, real-world applications, and smarter alternatives for solar energy systems and portable power setups. Let"s cut to the chase: A 12V 6W source provides 0. Can I use a 12V power supply on 6V? If the device has its own internal switching regulator, the voltage probably won"t be a problem, but since the 12V power supply has a lower maximum power (12V * 0. Use a deep-cycle battery and ensure the battery capacity is at least 20% of the inverter's wattage. This guide explains how to calculate wattage limits, optimize runtime, and avoid common mistakes when pairing batteries with inverters.