SSR or Mosfet to control my HB - Help please

Hello
I'm not a 3d printer guru as I just built a corexy working in decent manner..

I would like to add a heated bed, 25x25, I bought an ultimaker2 HB, 24V 230W.
To power it I will use a 24V 15A power supply and Ramps can't handle that kind of current/tension.

So I read around that I can use a SSR relay DC/DC large enough, I thought 40A will be..

Finding a good ssr isn't easy unless you pay a lot
I don't trust in chinese fotek clones as they can burn..

Do you know any (possibly european) source for good but still cheap SSR relays?

Another way to regulate tension for the heated bed is Mosfet, but I'm not aware on how to use it.
Does anybody know if there is any tutorial on how to build a circuit with a mosfet for a heated bed?

Thanks!

I don't like RAMPS myself, but it should be able to drive that heated bed directly. The bed heater input can take 24V (the other input only 12V), and your 230W bed heater will take just less than the 10A that RAMPS is comfortable with. However, you should replace the 11A polyfuse with an auto fuse, because the polyfuse is rated at 16V so it is likely to catch fire if you get a bed short with 24V applied.

If you do want to use an external switch, then the Power Expander form reprap.me ought to be suitable.

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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].

Thanks DC42
on the ultimaker 2 HB installation manual there is this indication

Quote

Technical specification
Electrical AC INPUT 100 - 240 V, Approx. 4 AMPS, 50 - 60 HZ 221 watt max.
Power Requirements 24 V DC @ 9.2 AMPS

This is the original one, I bought my one from aliexperss...
So there is no guarantee specs are the same..
May be better to buy a Power Expander, perhaps..

I have used some of those beds and they use less than 5amp at 24v. I think maybe ramps can actually deal with this on its own. Bed circuit is completely seperate so you can just feed 24v to bed power.
Edit. I have always a 5amp fuse in front of them, and not one has ever went poof.

Or use a power expander from reprap.me very nice product for future builds as well.

Edited 1 time(s). Last edit at 05/31/2016 04:36PM by dintid.

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Thanks dintid
at the end I bought power expander and all is ok
but are you shure this HB only takes 5A @24V??
I'm going to change my board from ramps to radds 1.5
This way I could power all the system with 24V 20A??

Quote
pieri70
Thanks dintid
at the end I bought power expander and all is ok
but are you shure this HB only takes 5A @24V??
I'm going to change my board from ramps to radds 1.5
This way I could power all the system with 24V 20A??

If yours are like mine then yes. I currently run a complete printer with this bed by a passively cooled 24v 10a psu with a 5amp fuse in front of the bed. PSU does not get overloaded. I recently added a down-volted small fan to psu though. Just to be safe

Edit. 24v 20a is way enough for your printer. I run mine on 24v 10a.

Edited 1 time(s). Last edit at 05/31/2016 04:51PM by dintid.

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My Instructables - both total newbie instructables and some for intermediate users.
My Designs on Thingiverse
YouTube channel containing a few 3D printing videos - they are videos for my Instructables, and mostly not standalone.
Ultius / Tantillus Thingiverse Group