Home Depot wire?

16-18 stranded is about right. House wire is thick but will work. Iirc car harness is fine strands for better flexibility. If your going big like under 10, get welding cable, it's very fine stranded and flexible like a welding gun cable. Good for battery runs to trunk. Automotive grade TXL/GXL/SXL wire withstands exposure to temperatures of up to 257°F (125°C) CHEAPEST TO MOST EXPENSIVE