200x300mm Heatbed Selection Help

Hi, first time poster here!

I have recently embarked on creating my first 3D printer, specifically the P3Steel V4. I have the majority of the electronics en route however I am still having an issue sizing the heatbed and thus the PSU.

The P3Steel V4 has a larger printing area, 200x300mm, and I wish to use as much space as possible. Thus I require a heatbed of this size, and thus is my issue. The heatbeds available for this size without creating my own are as follow (as far as I know, if anyone else has more please let me know):

1. RepRap PCB Heatbed 200x300mm. Dual power 12/24V - I have heard that these are garbage at this size and are extremely under powered?

2. 300W 12V 20X30cm Silicone Heater Pad,3D Printer HeatedBed,w/3M PSA & Thermistor - Better but at 12V would be drawing huge amperage. In the ad it states that this would draw up to 25A. I'm afraid this might be too much for my RAMPS board. Not sure what other issues this might cause or am I just being paranoid? Also 300W might still be a bit under power, but should be doable for ABS (... but maybe looking to print polycarbonate down the road).

3. 300W 24V 20X30cm Silicone Heater Pad,3D Printer HeatedBed,w/3M PSA & Thermistor - same as #2 but in a 24V version. This would be much more ideal as the amperage would drop to a much more acceptable level however using 24V on the RAMPS would require some altercations that I am not sure I am comfortable of doing. At lease I don't know of a sure fire way of doing this, iv read a little about SSR's but still haven't found nothing solid (preferably a video explaining step by step solutions on how to set/wire/solder everything up)

4. 600W 110V 200X300mm Silicone Heater Pad 3D Printer HeatBed w/ Digital Controller - IMO the best one but also more expensive than I'm willing to go (the Canadian dollar isn't doing to well right now either ). This definitely has the juice needed and is basically plug in ready to go with a digital thermostat.


Basically im looking to see if any of these would be a good option, or if anyone else as a better idea for heating a 200x300 printing area? I ideally would like to run everything off of one PSU but can do 2 if need be and would like to keep the amount of re-soldering to a minimum as im pretty inexperienced in that sense.

Any input would be greatly appreciated.

Cheers,
Taylor

RAMPS is for people who can't afford anything better and for kit manufacturers engaged in a race to the bottom. It is the wrong choice for a printer that is crying out for 24V electronics because it needs a bed heater with more power than the cheap 200x200 PCB. The money you save by using RAMPS will be eaten up by extra components such as a second power supply, or separate temperature controller, or good DC-DC SSR. So choose 24V-capable electronics, which will be able to drive a heated bed of that size directly. My favourite is the Duet, but the Smoothieboard and clones are also popular.

For a 200x300mm heated bed capable of reaching ABS printing temperatures, IMO you need an absolute minimum of 180W of heating power. I would aim for 250W. So the first bed you linked to is underpowered. Then second is 12V so not suitable. The third is OK. The fourth is AC mains powered, and while this is certainly an option (I use an AC mains powered bed heater in my delta printer), it brings additional safety issues that need to be addressed, particularly in a printer with a moving bed.

I suggest you ask these people [www.aliexpress.com] for a quotation to make you a 24V 250W heater to your size specification with thermistor. They made a bed heater for my delta printer to my specifications.

Tip: if you make the bed support a little larger than the bed heater and the printable area by about 15mm all round, this leaves room for bed supports around the edges, and clips to attach a glass bed plate - both out of the way of the bed heater.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].