Something is wrong. cutting out under 3 seconds is not normal, even if you under or over volted your steppers.
What drivers do you have, what stepping mode are you in, do you have active cooling on them, heatsinks? You really need to set them according to the data sheet of the driver and the stepper and usually 10-20% under for long term stability. What firmware are you using, are your steps correct, acceleration, pulley size, if your belts are too tight is can stall the steppers? Sounds like you might need to take a step back and check everything from top to bottom.
As an example even with a fan on the drv8825 drivers 1V is on the high end and you can get thermal shutdown if you have any cooling deficiencies, and that is greatly under volting the 72oz/in steppers. you might not be able to get enough power to your 84’s even worse if you are using the a49’s.