How to calculate stepper current.

I emailed the company, Alunar, and asked them for the spec sheet for my control board. I don't think I'm going to get it. They sent me a spreadsheet with a bunch of info on it but there's nothing on how to calculate what the stepper current is.

The stepper I more concerned with is the extruder stepper. I measured vRef (trim pot to ground) and it's 1.46v. There are two R200 resistors near the trim pot.

The reason I want to know is because I am having very inconsistent extrusions and just now the extruder stepper was clicking. It would basically move forward and bounce back. The only other time I saw that is if I tried to manually move the extruder stepper through the firmware by 0.1mm. My print just went to S@#$. I'm running the extruder temp at 220 and Im printing at 45mm/s.

I dont know if my stepper is getting the right amount of current. I just upped the vRef to 1.8v and tried again... it's actually printing pretty nicely right now without any problems. The thing is that if I try to print the same thing tomorrow using the same file/ configuration, I'll run into a whole boat load of problems before it starts printing nicely.

Anyone have any ideas?