My plan is to double the Y axis on my Taz 4. I'm getting ready to make the bed heater but need some help. So my plan is to make the heater 1.2 ohms maybe less, meaning it will draw somewhere around 20 amps, which I believe is a bit much for the Ramboard (I don't recall which version of the board I have, 1.3 or 1.4). Is there a mod I can to to it to make it able to handle that current?(I can replace board components), and if not, is there a way of controlling the current from an external PSU to the new heater? Is the power to the bed from the Rambo actually metered or is it simply an on/off situation where a solid state relay would suffice? The PSU has already been upgraded to a 500 watt unit so I believe I'm good there but I've even entertained going up to a 30volt PSU to get the wattage to the bed heater up without too much current, but do not know what else will end up with 30 volts (steppers, hotend). I also notice that the MOFSET the related to the bed heater is rated at 89 amps, yet the board rates the output on this channel as a maximum of 15 amps.

Any help will be appreciated