Hey all, I'm starting an ambitious build which uses 4x standard MK2B heatbed PCBs to heat up a large print bed. Obviously this is much more power/current than any of the usual controllers can handle (I'll be using a 32bit Smoothieboard or clone). I do have a dedicated power supply just for the heatbeds (720W) but the control is where I'm a bit unsure. I was just going to use some standard automotive relays but then it hit me that they'd only be a decent solution if it was kind of binary control (ie, heatbeds are either on or off) but I don't believe that's the case; MOSFETs generally vary current to the heatbeds depending on the required load, don't they? Eg, a cold bed would be heated at 100% but as it approaches the required temp, it might dial it back to 30%? I'm not quite sure how this works or what the best solution is... Any help would be appreciated! https://reprap.org/forum/read.php?1,576685,576685#msg-576685 Tue, 19 May 2026 03:18:17 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,576685,576874#msg-576874 https://reprap.org/forum/read.php?1,576685,576874#msg-576874 imqqmi General Thu, 29 Oct 2015 05:11:12 -0400 https://reprap.org/forum/read.php?1,576685,576810#msg-576810 https://reprap.org/forum/read.php?1,576685,576810#msg-576810 the_digital_dentist General Thu, 29 Oct 2015 00:48:06 -0400 https://reprap.org/forum/read.php?1,576685,576807#msg-576807 https://reprap.org/forum/read.php?1,576685,576807#msg-576807 pugzor General Thu, 29 Oct 2015 00:07:41 -0400 https://reprap.org/forum/read.php?1,576685,576802#msg-576802 https://reprap.org/forum/read.php?1,576685,576802#msg-576802
Just stick some relays in there and be done with it. I'm using a relay to control the heatbed on my printer, it works fine.]]> nebbian General Wed, 28 Oct 2015 23:46:55 -0400 https://reprap.org/forum/read.php?1,576685,576782#msg-576782 https://reprap.org/forum/read.php?1,576685,576782#msg-576782
I do already have the heatbed PCBs and the big DC power supply, so I guess I'm looking for a solution that matches that. I guess I'm kind of fond of using low voltage where possible too.]]> pugzor General Wed, 28 Oct 2015 21:27:23 -0400 https://reprap.org/forum/read.php?1,576685,576718#msg-576718 https://reprap.org/forum/read.php?1,576685,576718#msg-576718 dc42 General Wed, 28 Oct 2015 17:11:38 -0400 https://reprap.org/forum/read.php?1,576685,576685#msg-576685 https://reprap.org/forum/read.php?1,576685,576685#msg-576685
I'm starting an ambitious build which uses 4x standard MK2B heatbed PCBs to heat up a large print bed.

Obviously this is much more power/current than any of the usual controllers can handle (I'll be using a 32bit Smoothieboard or clone). I do have a dedicated power supply just for the heatbeds (720W) but the control is where I'm a bit unsure. I was just going to use some standard automotive relays but then it hit me that they'd only be a decent solution if it was kind of binary control (ie, heatbeds are either on or off) but I don't believe that's the case; MOSFETs generally vary current to the heatbeds depending on the required load, don't they? Eg, a cold bed would be heated at 100% but as it approaches the required temp, it might dial it back to 30%?

I'm not quite sure how this works or what the best solution is... Any help would be appreciated!]]> pugzor General Wed, 28 Oct 2015 15:54:36 -0400