While getting to grips with the electronics of the OX build, I notice that the TB6600 is rated at 2.5 amps. How can you tell, before turning it on what the rate is set at and how can you regulate it once the unit is connected to the power source. I can turn the blue box screw clockwise and anti-clockwise, but don't know where to leave it. No doubt there's a simple explanation for how this is done. Perhaps someone could enlighten me. Many thanks Michael.