Hi. How do I measure the voltage between the battery and the motor? I kinda don't understand that part. However, the voltage between the motor's positive pole and the MOSFET drain measures 2.79V. The voltage between the motor's positive and motor's negative pole is 2.71V (Reduced from previous post's reading 2.77V because of the battery discharge from running the tests I guess). The voltage between the motor's positive pole and the battery's negative measures 3.05V. (If that's what you meant by voltage between the battery and the motor). I'm testing these connections in a breadboard with a couple of jumper wires. The jumper wires have a resistance of approx 0.6 - 0.7 ohm. Could the resistance of my breadboard and jumper wires affect the voltage drop? Thanks!!!So that means the MOSFET is working fine.
The problem appears to be a voltage drop somewhere from the battery to the MOSFET.
Measure the voltage drop between the battery and the motor, and between the motor and the MOSFET drain.
What wire size are you using for the connections?