I sorry, but i did use the same size wire and factory connector. How i found out the problem, was to just use the existing wire from esc without extention and boat worked fine. Now that's why i asked and when no replies came, i took a chance with a thicker 3 wire lines and hooked it all up and ran like a charm. The lenght of original + extention was at least 14". I have some very pliable train wire that is same strand as the new wire setup and alittle thicker coating that will come in handy if and when i do it again. I'm not doubting you, but it worked. The trouble with extentions lenght of 12" is placement of extra wire. I hate cutting wire and soldering it as it looks like, you know what. Generally i cut, strip,solder,heat shrinl, and tape for insurance. Sorry for rambling on but made the most of what i had. This was in a Arpro 1 new setup with a 36 50 3300 inrunner with saddle bag lipos and had to put esc up front. I got the idea from Ferral of Australia in his new setup and got it real close to his. Rpm will be 27,+++ on 2S. Motor is a amp eater and have other motors like 36 40 05 3900 Turnigy which i use if it doesn't work out. I make my own cooling with pcv pipe and works great and never leaks. There i go again, sorry. I'm retired and have done this hobby for many, many years, only with brushed systems and still have them. I'm gone. Rereading your post, couple of bucks, not any more, gone out of sight with prices. Thanks for posting, i appreciate it.-**** I soldered the new heavier wire before i saw your post on esc. Maybe the extention wire may have been very old or even broken which is hard to tell when wire is covered. I see your building an airboat with a slopped front end. There's guy who builds airboats called Clasedesigns. He has a 16" of which i bought and a real winner and a blast to drive.I have 5other airboats i made that aren't lookers but are functionable and do move.