Add the continuous watts of everything running at once and match that to the inverter’s rating. A 2000 watt unit handles a laptop, a cell phone charger, hand tools, and a small refrigerator together. An air conditioner or a large air compressor usually needs a bigger inverter and a bank to match, and that is often where a 24 or 48 volt system makes more sense.

Motors and compressors pull several times their running current for the first second or two. An inductive load rated at 800 watts can demand 2400 watts at startup, so the inverter’s surge rating is what determines whether it starts at all. Our low frequency models carry three times their continuous rating in surge capacity for exactly this reason.

A low frequency inverter uses a heavy transformer, which gives it more surge headroom and better tolerance for repeated motor starts. A high frequency inverter is lighter, smaller, and less expensive, and it suits electronics and resistive loads. Pick low frequency when inductive loads are the point of the build.

Get an inverter charger if the build ever connects to shore power or a generator. The built-in transfer switch moves the load over automatically, and the battery charger refills the bank while you are plugged in. A standalone inverter is the right call when the battery is charged by solar or the alternator only.

A 2000 watt inverter pulls roughly 170 amps at 12 volts, which is why 12 volt builds need heavier wire than the wattage alone suggests. That calls for properly sized cable and a rated inline fuse on the positive run. Size the bank in amp hours for the runtime you need, and LiFePO4 handles that discharge rate better than lead acid does.