Mofset Max Current

(nevarore_SW) #1

Hi all,

The mosfets-table indicate a 12A for Maximum current for Big Mofset but on the smoothieBoard page, we can read : ‘These are two big mosfets : AOT240L rated up to 40V and 20A’.

I bought a 24v-14.6A psu to speed up my hotbed but I am not sure I can use it …


Imported from wikidot

(Arthur Wolf) #2


The mosfets are rated up to 20A ( or even more ), but the connectors are limited to 12.5A.
What is the current rating of your bed ?


(nevarore_SW) #3

Hi Arthur,

Ok thanks, I understand.
My bed is a mk2a heated bed with a 1.8 ohms resistance.
Wiki said: “The MK2 PCB heatbed heats up to 110C when powered through the heated bed connection on Sanguinolou, your power supply should be 300W and ensure your wires from your power supply to the Sanguinololu should be capable of handling the total draw of 20A+. Using a 300W ATX power supply with the 4wire ATX dual 12V connector is working well for me.”

My PSU could devliver 350W ( 24v-14.6a ). I have another 350W PSU 12V but the current could reach 29A !

Best regards.

(Arthur Wolf) #4

I think those beds are designed to take in 12V, not 24v.
There are special versions around that take 24v ( or can be configured for either 12v or 24v )