Using ptc heaters for a 400x300 bed ? Is using ptc heaters for a 400x300 bed the best option ? Thanks Nikki https://reprap.org/forum/read.php?4,609142,609142#msg-609142 Mon, 08 Jun 2026 16:47:18 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?4,609142,610383#msg-610383 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,610383#msg-610383
thanks nikki]]> Nikki81 Reprappers Sat, 16 Jan 2016 04:58:36 -0500 https://reprap.org/forum/read.php?4,609142,610332#msg-610332 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,610332#msg-610332 the_digital_dentist Reprappers Fri, 15 Jan 2016 23:47:27 -0500 https://reprap.org/forum/read.php?4,609142,610254#msg-610254 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,610254#msg-610254
As a rough guide, the MKII PCB heatbeds that everyone uses are about 120W for a 200x200 bed, and can only just get the bed to about 105C for ABS, that equates to 30W per 100mm^2, so to scale that up you need a minimum of 360W for 400x300. However because the MKII bed is underpowered you should probably aim to add 25% minimum to that figure, that gives you a starting point of 450W. This seller will make a silicon heater to your requirements (just specify dimensions, power, and voltage).

The next decision you have to make is what voltage to use, and how you will switch it (it's unlikely that the MOSFET on your controller board will be able to switch the current required for 450W). If you want to stick to DC then a 36V DC supply may be your best choice, and either use a 36V controller (and other electronics) or use a separate supply for everything else, however that will need an expensive DC/DC SSR to switch it. AC is easier to switch because a reasonable AC/DC SSR's isn't as expensive, another choice is to go with 24V and use one of these power expanders (they can handle up to 30V max), I've heard good reports of them and they are far cheaper than a SSR (the downside of that is that your heated bed wires will need to take about 18A).]]> plankton Reprappers Fri, 15 Jan 2016 17:26:29 -0500 https://reprap.org/forum/read.php?4,609142,610238#msg-610238 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,610238#msg-610238
Quote
Nikki81
ive just found this do you think it will be ok ? am not sure why there a 4 wires ???

That would be absolutely fine as long as you have a 220-240V ac supply the 4 wires are AC Feed and 2 for the inbuilt Thermitor (If it indeed has one it does say picture is for info if not you can ask for one to be installed or you can add your own) also be aware that you will need something like a DC - AC SSR to switch it but they are quite cheap anyway many of these chinese companies will actually make one to your specification and needs and I would think something around 400-500 watts would be enough.

HTH

Doug]]> dougal1957 Reprappers Fri, 15 Jan 2016 16:28:47 -0500 https://reprap.org/forum/read.php?4,609142,610229#msg-610229 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,610229#msg-610229 this do you think it will be ok ? am not sure why there a 4 wires ???]]> Nikki81 Reprappers Fri, 15 Jan 2016 16:11:30 -0500 https://reprap.org/forum/read.php?4,609142,609672#msg-609672 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,609672#msg-609672 ptc heater Thanks for the tip about silicone heaters ill have a look for one the correct size.

thanks Nikki]]> Nikki81 Reprappers Thu, 14 Jan 2016 15:18:26 -0500 https://reprap.org/forum/read.php?4,609142,609616#msg-609616 Re: Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,609616#msg-609616
A 400x300 bed would probably work with an ordinary silicone heater.]]> epicepee Reprappers Thu, 14 Jan 2016 13:17:48 -0500 https://reprap.org/forum/read.php?4,609142,609142#msg-609142 Using ptc heaters for a 400x300 bed ? https://reprap.org/forum/read.php?4,609142,609142#msg-609142
Thanks Nikki]]> Nikki81 Reprappers Wed, 13 Jan 2016 12:47:21 -0500