Source of 24 volt 20+ amp Power Supply

[msdevstep]

I had a cheap power supply I bought off ebay.

http://www.ebay.com/itm/261199349527?ss ... 1497.l2649

Well it now glows bright orange on the inside when the heated bed kicks on, so needless to say, I no longer feel comfortable using it. I imagine the Onyx bed is pulling more amps than it can supply. I was curious where everyone else got their power supplies? Hopefully it's fairly cheap as I've already put a ton of money into my printer.

[cambo3d]

what's glowing bright orange?

the onyx draws 18amps max.

not that it matters but that's a 14amp power supply you linked. what's more curious is what is glowing bright orange? just a light or something actually overheating?

[Eaglezsoar]

This is the Power Supply that I purchased, It can handle the startup current of the Onyx.

http://www.ebay.com/itm/Power-Supply-24 ... 3f23d6855d

[Eric]

The cheapskates route to 24V power supplies is to put two identical 12V supplies in series. This is practical because there are a lot of 12V server supplies that can be found cheaply on ebay. I picked up two 40A 12V supplies for $17 shipped last year (http://forum.seemecnc.com/viewtopic.php?f=12&t=889).

Note that putting power supplies in series requires modifying the supplies to float either the AC (easy, but creates a shock hazard) or DC (harder, but safer) grounds. If that sounds scary to you or your skillset, then it's probably not for you. You do this at your own risk.

Start here if you want to read about it: http://www.rcgroups.com/forums/showthread.php?t=1292514.

[msdevstep]

It appears to be a ceramic pill shaped cap. There is debris around it that looks to be chips of its casing and its the exposed leads that are glowing red hot. It only glows when the Onyx is drawing power. Other than the glowing, it still functions. Its good to know that the fuse right next to it doesn't feel like popping

[cambo3d]

It appears to be a ceramic pill shaped cap. There is debris around it that looks to be chips of its casing and its the exposed leads that are glowing red hot. It only glows when the Onyx is drawing power. Other than the glowing, it still functions. Its good to know that the fuse right next to it doesn't feel like popping

post photo,? which part in this pic http://reprap.org/mediawiki/images/a/a5/DSC07882.JPG

[msdevstep]

I'm sorry, I must not of done a very good job explaining what was glowing. Its actually a component inside the metal case of the 24 volt power supply unit. My RAMPS board is actually running off a 12 volt ATX power supply. The only component running off the failing power supply is the Onyx bed.

[cambo3d]

I'm sorry, I must not of done a very good job explaining what was glowing. Its actually a component inside the metal case of the 24 volt power supply unit. My RAMPS board is actually running off a 12 volt ATX power supply. The only component running off the failing power supply is the Onyx bed.

ic, i misunderstood you then, in that case return that power supply some of those are known to be bad out of the box. there cheap for a reason..

[msdevstep]

Do you think getting another 14 amp one would work for the Onyx or should I look for something bigger?

[cambo3d]

Do you think getting another 14 amp one would work for the Onyx or should I look for something bigger?

14amp will work just dial down the voltage a little to keep the onyx from overdrawing from the power supply, but higher amp wont hurt either. I'm using the same supply that eaglesoar posted.

onyx draws 18amps at 24v for few seconds at power up. then drops quickly to whatever current it needs for the set temperature.

[Broose]

I'm pretty much using the same supply. Here is what I am using.

http://www.amazon.com/gp/product/B007F7 ... UTF8&psc=1

My Onyx measured 1.6 ohms. I lowered the power supply to 21V with the adjustment pot on board

21V/1.6 Ohms=13.1A

I don't have an ammeter that can check to see if it surges more than that at first startup, but my supply has been working for months with no issues.

[darthviper107]

This is to get the heated bed to warm up faster right? For someone who knows nothing about electronics is there an easy way to do an upgrade like that? I'm not so much concerned about trying to find the lowest-cost solution, but I wouldn't know what to look for.

[JohnStack]

I'm pretty much using the same supply. Here is what I am using.

http://www.amazon.com/gp/product/B007F7 ... UTF8&psc=1

My Onyx measured 1.6 ohms. I lowered the power supply to 21V with the adjustment pot on board

21V/1.6 Ohms=13.1A

I don't have an ammeter that can check to see if it surges more than that at first startup, but my supply has been working for months with no issues.

I'm still unclear as to why an additional power source is needed? Bed heat times? More accuracy in temps? I'm not that concerned but heat times - but precision, yes. Does the additional PS make it worth it?

[Broose]

I'm still unclear as to why an additional power source is needed? Bed heat times? More accuracy in temps? I'm not that concerned but heat times - but precision, yes. Does the additional PS make it worth it?

Here's an explanation of why folks are looking to increase the voltage to the Onyx to decrease bed warm up time.
http://forum.seemecnc.com/viewtopic.php ... +law#p7284

[Gr8Scott]

I increased my power supply to be able to heat a larger thermal mass than just the Onyx by itself. I have a large and thick cast aluminum heat spreader fastened on top of the onyx and that much larger thermal mass requires a much larger power source to get up to temp in a decent time frame. I'm running my 1.3ohm onyx at almost 20 amps at 24 volts and it still takes me 5 minutes to reach 100 degrees C. I bought the large thick chunk of aluminum because it was cheap and it was milled perfectly flat.

[kbob]

I'm still unclear as to why an additional power source is needed? Bed heat times? More accuracy in temps? I'm not that concerned but heat times - but precision, yes. Does the additional PS make it worth it?

For ABS, I'd like the bed to be 100-110℃. I haven't gotten the Onyx up past 90° on 12 volts.

[jesse]

How fast does the Onyx reach temperature with higher voltage/amperage power supplies?

[cambo3d]

http://forum.seemecnc.com/viewtopic.php ... =150#p7627

http://forum.seemecnc.com/viewtopic.php ... =170#p7960

[msdevstep]

Just wanted to say thank you to everyone that responded.

Cambo3d and Eagle, thanks for the recommendation on the power supply. I'm currently using it with no problems thus far. The one thing I will say about it though is it's loud. The fan stays on full blast the whole time. It doesn't bug me that much, but I just wanted to mention it for anyone else that may be needing a power supply.

PSU Setup

[cambo3d]

I run two printers off this same power supply, so it serves me well, yes it is loud though.