Measuring by V-I method is the accurate method. In idle condition, inject about 6-12V battery supply and measure the voltage(V) drop across the winding and the current drawn(I) using accurate, calibrated meters. Resistance =V/I. The winding resistances usually will be very less. So to safe guard the battery from getting drained use about 10 ohm in series. All R&D units and labs follow only this method.