RAMPS on 24V
Hint: Current OSE strategy for 24v is: (1) 24v power supply; (2) cut off diode on RAMPS to stop 24V from going into Arduino Mega; (3) feed power to Arduino with 5V wall wart and USB A to B cable; (4) power the SSR with 5V that feeds from this wall wart via Auxiliary Pins -> upper part of Green Power Plug (normally 12V - it feeds into the D8 internally) -> D8 terminals -> SSR
- Cut off Arduino power, but need to feed Arduino with power in a different way.
- If using external heat bed mosfet - no other change needed.
Do Stepper Motors Work Better at Higher Voltage?
- Steppers have less torque at higher speed
- Power of a stepper is constant - if power is torque x velocity, then torque decreases with higher velocity
- The mechanism for loss of torque is back EMF from inductance and back EMF from rotation
- With high velocity, back EMF of inductance is significant as a fraction of motor power. At high enough speed, inductance overtakes and motor stalls. This is the region when higher voltage allows stepper motor to overcome the effect of inductance. So at Max speed - higher voltage produces more torque for a stepper motor.
- 24V Power Supply
- 24V to 12V converter - 5A for using 12v heaters, fans - 
- $14 for 10A - 
Cut Off D1 Diode
Replace Automotive Fuse
See at minute 1: