PSU Options for RAMPS 1.4 and Mega 2560 R3

Hi,

I'm building a 3DR Delta Printer with no heated bed and was looking for some advice over power options.

I was originally going to use an X5 but, with the unknown lead times, I'm impatient to get something working so have ordered a cheap RAMPS 1.4 + 2560 R3 with Full Graphic LCD kit to get started.

I have a nice compact Sony 19V 6.5A laptop power supply that I thought would be ideal for the X5. Is this still a sensible option for the RAMPS/Mega combo or am I better hacking an ATX PSU for now and using the Sony when the X5 arrives? I read that there is a diode modification for the RAMPs to make it accept the higher voltage but are there any drawbacks to the solution once this is done? The R3 spec says 20V maximum so I'd be pretty close to the edge with this one.

Wife Acceptance Factor is important with this build, and the laptop PSU looks a hell of a lot more tidy than an ATX, but I don't want to introduce problems for the sake of (temporary) appearance.

Thanks in advance.

adavidm

If you use a 24v supply you need to remove the diode but I don't think you HAVE to remove it if you're only running 19v. However you're right at the limit of the regulator and it's going to disipate those 14 extra volts in the form of a lot of heat. It wouldn't surprise me if you drasticly reduce the life of the MEGA board's regulator operating it at that voltage, especially if you have little airflow on the regulator due to the RAMPS board. I'd look at building a small regulator on a separate board that efficiently knocks the power down to 5V for the arduino to use.

Thanks for the explanation, makes sense.

I think i'll go for the hacked ATX for now. No sense in risking damage for a short term issue.

adavidm

I would skip ATX psu's. If you want a power brick and have no intention of getting a heated bed, then why not find a decent 12v PSU. I tried converting the ATX psu converted and to be quite frank it stank at maintaining stable voltage even with minimal load on it. Think 20W. Then I added resistors to the 3.3v and 5v rail and it got marginally better. So I completely scraped the ATX psu and went for a server psu with massive amperage. I am running a heated bed and plan on running 12v heaters for a heated build chamber....

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Modicum V1 sold on e-bay user jaguarking11

ATX PSUs should actually improve as they get more load (from what I understand), and need at least a minimal load to work at all.

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jaguarking11
I would skip ATX psu's. If you want a power brick and have no intention of getting a heated bed, then why not find a decent 12v PSU. I tried converting the ATX psu converted and to be quite frank it stank at maintaining stable voltage even with minimal load on it. Think 20W. Then I added resistors to the 3.3v and 5v rail and it got marginally better. So I completely scraped the ATX psu and went for a server psu with massive amperage. I am running a heated bed and plan on running 12v heaters for a heated build chamber....

Hmm, I've got access to a number of server PSUs. Dell 1950, 2950 mainly, with a few Ablecom models thrown in. I've often worried about noise though, as these things sound like jet aircraft taking off. How quiet can they go? I do like the current specs though, I think 60A is the smallest I have!

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adavidm

Quote
jaguarking11
I would skip ATX psu's. If you want a power brick and have no intention of getting a heated bed, then why not find a decent 12v PSU. I tried converting the ATX psu converted and to be quite frank it stank at maintaining stable voltage even with minimal load on it. Think 20W. Then I added resistors to the 3.3v and 5v rail and it got marginally better. So I completely scraped the ATX psu and went for a server psu with massive amperage. I am running a heated bed and plan on running 12v heaters for a heated build chamber....

Hmm, I've got access to a number of server PSUs. Dell 1950, 2950 mainly, with a few Ablecom models thrown in. I've often worried about noise though, as these things sound like jet aircraft taking off. How quiet can they go? I do like the current specs though, I think 60A is the smallest I have!

I have an IBM branded delta PSU, I was lucky enough to get a psu with an 80mm fan, so I replaced it with a more silent one. Avoid psu's from 1U or 2U servers as they are very slim and usually have these compound 40mm fans that operate at over 10k rpm. Now as for cooling, I have not yet put my psu under any significant load, however I can say with the stock fan it made a mild inconvenient noise, with the coolermaster fan I had laying around it is completely silent, however the fan is load and temperature controlled, once the psu heats up I don't know yet if the 80mm fan will be enough. I am going to put my thermal probe on it. However even then they do sell some high CFM quiet 80mm fans that are in the 80x38mm range. If that does not cure it I will pop the stock fan back in there. Time will tell.
EDIT: take a look at my blog for the type of psu I used and how It looks etc, if for nothing more than to give you some ideas.

Edited 1 time(s). Last edit at 06/23/2014 06:22PM by jaguarking11.

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Modicum V1 sold on e-bay user jaguarking11

Will do, thanks

I think I've got some 6600 PSUs around somewhere. They have a non-standard kettle lead IIRC though.

Thanks again.

David

I've acquired a Dell V85 PSU which outputs 12V only at 12.5A, which sounds pretty good for a non-heated bed machine. I'll have a play with the server PSUs for a different project though.

Thanks for all the advice.

adavidm