12 volt, 14 gauge extension cord

I recently bought a small, portable air compressor to "top off" the pressure in the tires of my fifth wheel. It runs off my truck's cig. lighter. The cord is not long enough to reach my FW tires and I'm having a hard time finding an extension cord that will handle 15 amps. It's my understanding that 14 gauge wire is the proper size. Any thoughts on where I can buy this? Or do I need to wire one myself?

I'd go lower gauge. Not only is 14G only rated for 6A for transmission (which IMO this is; ratings being from powerstream's American Wire Gauge Table) but you'll lose 0.25V per meter. As to extensions, I usually make my own using 50A Anderson Connectors (with at least 50A rated wiring of course), but that's because I have various Anderson to other connector interfaces (cig plugs, Merit (Euro cig) plugs, splitters, etc) and lately an Anderson plugged remote control box (garage remote controlling a 60A relay with 50A self resetting circuit breaker) so I don't have to off-on at the pump when moving between tyres.    I'd suggest google images for 12v extension cable - maybe with anderson or merit options. Or replace the cable with a heavier cable etc.

Thanks for the advice. I guess I'll go heavier gauge and look for the Andersons. G'day!