Thank you for your fast reply.
I was using series wiring. But for measuring the current i disambled some of the stepper motors and made the measurements on only one.
For PSU i have 12V 30A charger and got on Ramps 1.4 around 0.2A current, while it was running idle with LCD screen. Which i think is OK.
When i was testing the current on the stepper motors i put it in full step mode, so the current is 100% and 0% for easier testing and moved them with the LCD controler for 1mm.
So if VREF = 0,76V (0,9* 1,7A / 2) the current on coil in full step mode should be around 1.1A (71%)
I basically got it 0,46A which is a bit lower than 70% of VREF.
I get a filling that VREF should be the same as stepper motor current, but not sure why.
I checked the thread - Current limit Stepper drivers drv8825 - #25 by coreire and got much more insight for how it works exactly.
I will see later today what resistors i have on the drivers and hopefully get a logical explanation for why it works like that.
The wires should be OK as i tested with the ones that comes with the motor and measured on 3 different DRV8825 drivers. I don’t think all the drivers are faulty.
Is there a problem if i run drivers on lets say VREF 2V if the current on the coil is at that setting 1.2V in full step or can the driver overheat?