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Prusa i3 power supply

Posted by Crux 
Prusa i3 power supply
May 25, 2013 07:20AM
Hi.

Can I use a spare computer atx power supply?

It's a 2HX DNA 500W

Is this a good choice? Or should I use something else?

What are you guys using as a power supply on your prusa?

Thanks!
Re: Prusa i3 power supply
May 25, 2013 08:30AM
i just got of the carboot was a 360 psu also i have the female connector to make things a little easier when it comes to wiring meaning i don't need to cut the psu just have the wires coming from the connector
Re: Prusa i3 power supply
May 25, 2013 03:22PM
Lots of people start out using ATX PSU

BUT some have issues of not giving true 12V unless the 5V line or 3.3V lines are under a small load and you end up messing with resistors.

really to be true and proper not to mention a hell of a lot safer and cleaner.

Get a 12V 20A PSU from Ebay/amazon. There around the same price as a ATX PSU anyway.

Just you have to buy the running wire (thats the AC side as well as the DC wire for extruder and Heated Bed)
Re: Prusa i3 power supply
May 25, 2013 03:41PM
Thanks for the replies.

Those PSU on ebay are ugly.

Is there something similar to a laptop charger with 20A? That would be great
Re: Prusa i3 power supply
May 25, 2013 04:36PM
Crux Wrote:
-------------------------------------------------------
> Thanks for the replies.
>
> Those PSU on ebay are ugly.
>
> Is there something similar to a laptop charger
> with 20A? That would be great

You can get a 203W Xbox 360 power supply, and either cut the end of the connector off or buy a Xbox slip adapter. Then just connect the red and blue wires together or through a switch to turn the power supply on.


Cameron

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Re: Prusa i3 power supply
May 25, 2013 04:44PM
I second Enlightx get a 12V 20A PSU. I just switched from a atx power supply to a 12V 20A PSU. The atx power supplies I found are not worth it With a atx you get too many cords, fan noise, its big and limited options for power. The PSU is small and just works. You can hook up a switch and print a front cover for it. See here
Re: Prusa i3 power supply
May 26, 2013 03:26AM
Thank you for the replies.

I wilil buy one on ebay then.

Check the picture attached. Should I connect the 12v to Ramps 1.4, or to the Mega 2560? Or maybe on both?

I am confused smiling smiley
Attachments:
open | download - 1_ramps_full-800x800.jpg (65.1 KB)
Re: Prusa i3 power supply
May 26, 2013 03:50AM
why not go down the 360 root it will be easier I bought a Xbox 360 203w psu for £5 and a female connector on ebay for £4 quid, i bought some fotosensitive pcd board the plan is too mount the female onto that and run the pins through the wire traces so organise it to be easily be soldered with 3 12 v rails on supply the 5 amp and 11amp on the ramps and the spare to power the fan for cooling the drivers and then the 5v to the switch and be be a led another reason to mount the female connector it be easier to mount in a box once my printers built and calibrated. im new to electronics and i seen how to make the pcb layout only thing i don't know is, how to trace the pin pattern?
Re: Prusa i3 power supply
May 26, 2013 04:25AM
Crux Wrote:
-------------------------------------------------------
> Thank you for the replies.
>
> I wilil buy one on ebay then.
>
> Check the picture attached. Should I connect the
> 12v to Ramps 1.4, or to the Mega 2560? Or maybe on
> both?
>
> I am confused smiling smiley

To the Ramps - see picture here [reprap.org]

The XBOX 360 PSUs seem OK, personally I just cut the connector off and strip the wires.

Another source of cheap PSUson ebay is PSUs pulled from servers, but they need some soldering.
Re: Prusa i3 power supply
May 26, 2013 04:46AM
thank you bob, but my question is: do i need to power the arduino mega 2560 too?

In this picture: [forums.reprap.org] both red arrows point to a power pinout. Should I connect both to 12v?

And I believe xbox 360 charger is about 12A. Is this enough?

Edited 1 time(s). Last edit at 05/26/2013 04:50AM by Crux.
Re: Prusa i3 power supply
May 26, 2013 05:10AM
Crux Wrote:
-------------------------------------------------------
> thank you bob, but my question is: do i need to
> power the arduino mega 2560 too?
>

No. smiling smiley With the standard setup for 12V, the Arduino gets power from the RAMPS board.

>
> And I believe xbox 360 charger is about 12A. Is
> this enough?

There are several different PSUs for Xbox, make sure to get the 203W version which gives 16.5A, which should be enough with a bit of spare.
Re: Prusa i3 power supply
May 26, 2013 05:20AM
Thank you.

Thats it. Will get a 203W xbox psu. Thanks!

It will sure look good. I dont like those ugly psu on ebay that everyone is using smiling smiley
Re: Prusa i3 power supply
May 26, 2013 05:20AM
xbox 360 203 watt version is 12v 16.5a and 5vsb 1a yes its easy to cut the wires of but i think of safety, as doing it my way the connector will be enclosed no wires showing no spliced wires the psu will stay as normal at the moment trying to measure the hole spacings to make a pcb board for the connector to sit on and easier to solder the pins ill post the pcd layout once done
Re: Prusa i3 power supply
May 26, 2013 06:27AM
Crux Wrote:
-------------------------------------------------------
> Thanks for the replies.
>
> Those PSU on ebay are ugly.
>
> Is there something similar to a laptop charger
> with 20A? That would be great

Dell has an 18amp PS. Found mine on ebay by searching Dell d220. Below article has instructions for connections:
[lbmakersociety.org]


Thingiverse ID Alan1279
Re: Prusa i3 power supply
May 26, 2013 07:14AM
Reading around, it seems the power brick (XBox etc) may be a little light on current, depending on how much your heatbed draws.

Since PSU questions are perennial, I have refreshed the wiki page at [reprap.org]. I think I have covered the main types.

I wanted to keep that page as a summary without getting into too much detail on how to wire up particular supplies, but if anyone has links to useful info please add them, or post them here and I will add them. Also any errors please flag them!
Re: Prusa i3 power supply
May 26, 2013 10:17AM
16.5 amps should be just on the margin but just a cheaper option than buying a led power supply just at the moment having difficult laying custom pcb board for the female connector to sit on
Re: Prusa i3 power supply
May 28, 2013 07:56AM
im using a 12vDC 20A 240W Power Supply from lulzbot
Re: Prusa i3 power supply
May 29, 2013 12:36PM
Could I get a second opinion if 16.5A from xbox 360 psu will be enough for a prusa i3 with the hot bed like this: [img.fystore.com]

Did anyone use this kind of configuration?

I am going to get the xbox 203W psu tomorrow. Thanks
Re: Prusa i3 power supply
May 30, 2013 01:14PM
I read earlier that 15a is not enough to run the hotbed.. so I feel 16.5 amps is getting close to 15a yes ? Personally I'd feel more comfortable running with 20a
Some users even run 2 separate power units to the bed & controller.
Re: Prusa i3 power supply
May 30, 2013 04:21PM
@Mickman, I agree.

It depends on which heatbed, but the "standard" Mk2a should have a resistance around 1 ohm, perhaps in the range 0.8 - 1.2 ohms. At 12V, that is 10-15A. Small variations in resistance can lead to a large difference in current.

But for a nominal 1 Ohm heatbed drawing 12A, say 2.5A for hotend, plus 2.5A for motors that adds up to 17A, so it is quite marginal. I think for a decent margin, 20A would be preferable.

I am running a 30A server PSU, and it barely gets warm. They really are a bargain if you can handle a little soldering. I have several spare standard ATX PSUs but I find the wiring too thin for the heatbed, some people find the Molex connectors burn out. I also have an XBox PSU, I haven't got that printer set up yet so I don't know how it handles a full load.

It does depend on what PSUs you can get cheaply wherever you are, and running two supplies is always an option.
Re: Prusa i3 power supply
May 31, 2013 05:53AM
How you work out 17 amps my drivers only take 2amps also I wont be running them top limit,also you only have 11amps and 5amps on the ramps, so 16.5amps should marginly do it ill post pics of ny 360 hack tonight once done
Re: Prusa i3 power supply
May 31, 2013 03:42PM
I already have the xbox 203w psu.

i's post here if it works, when i test it.

thanks.
Re: Prusa i3 power supply
May 31, 2013 04:31PM
I use an xbox 360 psu and i can run an 8x8 heatbed. Hotend and bed heat up better and faster then my old 25amp atx psu. It works really great and has a lot of power, heat etc protection. Plus the size and connector are convenient. I have a post on my WordPress blog on how to modify your xbox psu for are reprap. The WordPress link is attached to my signature.


--------------| For Everything 3D |------------------------------------------------------| Find Us At |--------
Check it out here: [reprapsquad.wordpress.com]. Twitter: @REPRAPSQUAD
Re: Prusa i3 power supply
June 01, 2013 02:01AM
Last night i finished my xbox 360 it has a fan spliced into it of the 11 amp sided connection the fan has a 0.09amp rating

heres the picture


photo 7b37405f-f6d2-4f9d-8172-222917b08e4d.jpg
Re: Prusa i3 power supply
June 01, 2013 02:38AM
chris33 Wrote:
-------------------------------------------------------
> Last night i finished my xbox 360 it has a fan
> spliced into it of the 11 amp sided connection the
> fan has a 0.09amp rating
>
> heres the picture
>
>
>




what are all those connections?

thats that on the thin wires?

also, what is this box for? [i663.photobucket.com]

whats inside it?
Re: Prusa i3 power supply
June 01, 2013 02:56AM
the 360 there's only one connector which is the ramps, 12awg wire spliced to 360 two spliced in to two 12vs and 2 gnds, there was 3 12v 3 gnds on 360 id say four because when i cut the connector end of there was two 12v spliced together and 2 gnds spliced together, then took the switch of the power enabled and the 5vsb, spliced in the wire on the 11amps side for the fan to cool ramps and electronics the box with the atx case is no longer it was a quick make to test a stepper motor
Re: Prusa i3 power supply
June 02, 2013 03:18AM
ATX power supplies are better than those cheapo PSUs on eBay/Amazon because they're warrantied, made to higher standards to achieve certification, and work well. Short circuit protection makes a huge difference - if you're away from your reprap and something goes wrong with moving wires would you rather have a PSU that's designed to shutdown or one that keeps on running? Not to mention a certified PSU is likely to have cleaner power than a non-certified one?

360W works fine with a decent, efficient PC PSU that has two (2) 12v rails and a machine that has one heatbed and one extruder, and a couple/few 12v fans. I've even added other low-current accessories like 5v breakout boards and such without a problem. What matters is having a total rating of about 30 Amps on the (two) 12v lines. Also each line has to have enough current (amps) - somebody probably stated what each line needs. A 400W or higher PSU is even better and will run cooler, but the tradeoff is a larger footprint. I don't know how much you need for dual extrusion yet.

The PC PSU with an ATX adapter board works great in my opinion. I like having the extra 5v and 3.3v lines, and I can't say how many times the short-circuit and over-current protection have kicked in during normal calibration and usage...and you won't even know those events occurred with PSUs that lack the certification (or are broken). In other words, that no-name PSU with unknown (or no) certifications might leave you blissfully unaware that your machine is driving too much current or has a short (or intermittent short) - and would you rather know or be blissfully unaware of such things? If you're not sure then you should probably get a PC PSU right away.

For what it's worth, the no-name brand PSUs actually have a name it's on the label on prod. photos if you look closely, and when you receive it (usually). You've been warned.

Edited 7 time(s). Last edit at 06/02/2013 03:49AM by tenacious.
Re: Prusa i3 power supply
June 02, 2013 04:10AM
well tenacious the 360 psu hack i think is easier hack then a atx power supply, in my opinion because it was straight forward, i was just making it harder for myself to incorporate the female connector, and if the anyone not going to hack a psu then led strip lighting psu will be better for those people.
Re: Prusa i3 power supply
June 02, 2013 07:17AM
Actually the xbox psu has great power protection, overtemp protection, over current protection and a few others. Don't let the price fool you. It has plenty of power and outputs for your reprap needs. It has been proven to work on hundreds of machines. In my opinion it works better than most atx psus, unless your willing to spend good money on a specialized psu or a top name atx psu like corsair. It heats up faster than quite a few different atx PSU s ive used in the past and can easily power hotend, electronics and an 8x8 heatbed which for most users is the top of their requirements.


--------------| For Everything 3D |------------------------------------------------------| Find Us At |--------
Check it out here: [reprapsquad.wordpress.com]. Twitter: @REPRAPSQUAD
Re: Prusa i3 power supply
June 02, 2013 01:48PM
REPRAP SQUAD Wrote:
-------------------------------------------------------
> Actually the xbox psu has great power protection,
> overtemp protection, over current protection and
> a few others. Don't let the price fool you. It has
> plenty of power and outputs for your reprap needs.
> It has been proven to work on hundreds of
> machines. In my opinion it works better than most
> atx psus, unless your willing to spend good money
> on a specialized psu or a top name atx psu like
> corsair. It heats up faster than quite a few
> different atx PSU s ive used in the past and can
> easily power hotend, electronics and an 8x8
> heatbed which for most users is the top of their
> requirements.





thank you for the reply.

Thank you all for the help. I have bought the xbox 203W / 16.5A and will use that. If that doesnt work, I have a spare 2HIX atx psu (24A on 12v) to use.
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