Suggested WIRE Sizes for Common 12v Inverters:

These suggestions are for PURE COPPER WIRE ONLY. The best copper wire is often called “Welding Wire” because it is rated for high amperage usage as well as high heat tolerances. I DO NOT recommend using copper clad aluminum wire for anything. It’s dangerous and you risk causing a fire. It can be tempting to use the minimum you can get away with because the price of copper wire is rather expensive, but my best advice is to think of wire as an investment for the long term in your solar system, this is not the place to skimp. With that in mind, I recommend getting even thicker wire than recommended if you plan on upgrading later because you can always use bigger wire that is over rated even on smaller inverters. So, say you plan to start with a 1000w inverter, but you have plans to upgrade to a 2000w inverter later, it would be a good cost saving measure in the long run to go ahead and buy 1/0 wire now and use that for your 1000w inverter, and when it’s time to upgrade to 2000w you don’t need to replace the 2 awg you already paid for, and then buy 1/0 later. Copper wire goes up year after year, and it lasts for ages, so get the biggest wire you can and save yourself money in the long run.

If you intend to use your inverter for a sustained period of time you definitely want to go with the “Recommended” size or larger rather than the Minimum wire size. The minimum size is ok if you only really plan to use your inverter at around 50% of it’s rated power most of the time, and an occasional max usage for less than 30 minutes or so at a time.

Note: These suggestions are for wire runs of LESS THAN 10 feet. If your wire lengths NEED to be longer than 10 feet, you should reconsider your options on the placement of your battery and inverter to bring them closer, otherwise you are going to need thicker wire… the longer the wire run the thicker the wire needs to be and for this I recommend doing more research before using these suggestions.