Per Castle Creations, the total length of red and black wires from esc to battery should not exceed 18 inches, ( black wire 9 inches plus red wire 9 inches = total 18 inches). Longer esc to battery wires have voltage spikes which degrade the special electrolytic capacitors causing the FET's to overheat resulting in esc failure and a crash. BTW, it is ok to use fairly long wires from esc to motor if needed. I reduced the total esc to battery wires to 18" in my GWS ME-262 twin brushless jet model by relocating esc's from nacelles to inside the fuselage and running longer wires from esc's to motors. You can use longer esc to battery wires by adding more special type capacitors to the wires however this gets quite technical.