Topic: Double bed heater
A while back I posted pics of my all metal gantry and extruder hack:
http://www.soliforum.com/topic/15488/my … metal-sd3/
In that post I was annoyed that that the new MK2 PCB bed running at 24V was no faster heating than the original equipment 12V silicone pad.
Solution:
Short answer: Connect the MK2 and the silicone pad (I left it on as insulation) in series and run them at 24V. Heats up in 7min.
Longer answer: The MK2 bed measured 6ohm across the 24V leads and 3ohm across the 12V leads (duh). The silicone pad measured 2ohms. Wired the MK2 for 12V and connected it in series with the silicone pad. 3+2=5ohms.
20% power increase form 96W to 115W. Current increases from 4A to ~5A. That is okay for me since the the 24V supply is good for 15A and I am running it through a 30A solid state relay controlled directly from the original bed heater MOSFET on the Sanguinolulu.
Maybe should run the bed PID routine, but the glass does a good job of damping the power bumps.
Did I mention it heats up in 7min.