Get a 12-gauge outdoor extension cord.

Yes, a 12-gauge, outdoor-rated cord will handle Level 1 (120V) EV charging at 25 feet without any issues. Don’t go thinner.

Level 1 charging pulls 12 to 16 amps continuously for hours. That’s way more than a toaster or power tool running for a few minutes. A 14-gauge “heavy duty” cord from the hardware store is not heavy enough for this job – it’ll heat up, drop voltage, and possibly trip breakers or damage your charger.

12-gauge (or even 10-gauge if you want overkill and a stiffer cord) is what you need. Make sure it’s rated for outdoor use (marked “W” or “W-A”) and has a molded, weather-resistant plug. Check that the cord’s plug fits your EVSE (charger) – some have bulky handles that don’t work with cheap flat plugs.

One more thing: don’t coil the cord while charging. Keep it spread out so heat can dissipate. And inspect it regularly for cuts or damage.

This is not where you save ten bucks. A proper cord costs $30-40 and lasts decades. The wrong one causes problems you don’t want to deal with at 2 AM.