Everything fired up fine the first time, just had to switch the polarity on the 2 wires from mosfet to board. Now I think I just have to re-solder the thermistor wires because it's not reading temps anywhere near correct. The enclosure temp is 18c but the bed temp is reading 70c.

Are you using stock firmware or Repeitier? If stock nothing should change. If Repetier you will need to change the beds thermistor to a standard 100K thermistor like the hotend uses. The XYZ machine do not use s normal thermistor for the bed and if you don't make a mounting location under the heater for a standard thermistor you will not get correct readings. Repetier does not have a table for the thermistor that XYZ uses stock.

Dan927 wrote:

I've looked at like 10 different schematics, this one: https://3dprint.wiki/_media/reprap/elec … jpg?cache= seems to be the one with the most info, but since its not the same board or Mosfet I just want to make sure that I'm doing this right.
Also keep in mind that I'm keeping the original PSU in to power the extruder and everything else but the heated bed, it seems like its gonna be a pain to remove it, so I'm wanting to power just the heated bed with this secondary PSU.
I'm using this Mosfet https://www.amazon.com/ANYCUBIC-Printer … merReviews.

If you look at the 7th picture on the Amazon page it tell you exactly how to connect it. The RAMPS connection is just the connection on the RAMPS board that the normal bed would be connected to.

Also that link for the schematic cannot be viewed. The owner does not allow hot linking.

I see, I will power it on and hopefully nothing explodes. Also added the picture of the schematic instead of linking it.

I've looked at like 10 different schematics, this one: https://3dprint.wiki/_media/reprap/elec … jpg?cache= seems to be the one with the most info, but since its not the same board or Mosfet I just want to make sure that I'm doing this right.
Also keep in mind that I'm keeping the original PSU in to power the extruder and everything else but the heated bed, it seems like its gonna be a pain to remove it, so I'm wanting to power just the heated bed with this secondary PSU.
I'm using this Mosfet https://www.amazon.com/ANYCUBIC-Printer … merReviews.

If you look at the 7th picture on the Amazon page it tell you exactly how to connect it. The RAMPS connection is just the connection on the RAMPS board that the normal bed would be connected to.

Also that link for the schematic cannot be viewed. The owner does not allow hot linking.