Hi,
I have got O drive S1 and 150KV motor. I am using male bullet connector that came with motor to connect to controller but seems like they are too big. What is the best solution here? Or am I doing something wrong. I have already ruined one motor winding ( good learning) before in search of better connections, it would be good to confirm this time before I do any stupid things haha.
Thank you for the help. 
Hi! Which motor are you using? Usually you solder to the end of those mating bullet connectors, but you need to make sure the connector size is correct.
Hi, I am using D6374 with ODrive S1 controller
It should have come with mating bullet connectors, I’d recommend using those. You just have to solder a wire to the end of it. These guys use a butane lighter, but I’d strongly recommend a proper soldering iron instead 
How to solder a bullet connector | Flite Test
Thank you! and what gauge size wires do you recommend to get minimum resistance
For the D6374, 12AWG should be just fine. 10AWG is technically ideal if you’re going to be maximizing the motor current at 70A all day, but realistically you’ll likely not be pushing it that hard. The resistance in the wires will be quite small relative to that of the motor, it’s really just wire heating to be concerned about, but 12AWG should be a fine fit.