PSU Upgrade to 350W for MK3/MK3S  

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thaddeus.a
(@thaddeus-a)
Active Member

Just very successfully upgraded to a higher capacity PSU, a Meanwell NES-350-24 (available on Amazon), and used this case/mount from Thingiverse: https://www.thingiverse.com/thing:3082178

Very happy with the upgrade, always felt the original PSU was pushed too close to its power limit with 240W, want to keep below 80% of rating as much as possible. Yes, my old PSU broke, fuse blown, PSU unresponsive, no damage to Rambo board, right after the MK3S upgrade (well 3 prints in).

Only complexity in the upgrade was the power cables were literally 20mm too short, too much strain, so I needed to extend them a bit for safe cable management, etc.

This topic was modified 1 year ago by thaddeus.a
Posted : 04/06/2019 8:04 pm
Migamix
(@migamix)
Trusted Member

did the same. didn't remount to frame, it lays on the bottom of my lack so it can get some fresh cooling air from the enclosure cracks. fan blows up. the extra rail has a buck converter I will be using for powering LEDs and other 5 volt devices such as the circuit playground I use for auto lights for the picam (currently plugged into pi USB).

and we’ll be saying a big hello to all intelligent life forms everywhere … and to everyone else out there, the secret is to bang the rocks together, guys....
Posted : 09/07/2019 7:12 pm
thaddeus.a
(@thaddeus-a)
Active Member

Nice idea on the extra rail to 5V for other devices versus driving through the Pi USB. If you have a recommendation/link, would love to see it.

Posted : 09/07/2019 7:33 pm
david.a66
(@david-a66)
Honorable Member

you probably want to make a replacement brace to replace the bracing that the power supply added to the Z axis

Posted : 09/07/2019 8:57 pm
paul.m27
(@paul-m27)
Honorable Member

I think the official DIY enclosure kit from prusa gives an stl for a printable replacement brace.  Their plan allows moving the PSU outside the enclosure and therefore needs the brace.

 

Posted : 10/07/2019 5:58 pm
guy.k2
(@guy-k2)
Noble Member

Watch out for the bolt heads on a replacement bracket. I discovered months later that mine could obstruct the x-carriage if z was at just the right height. Cap head screws instead of hex socket screws fixed the problem

Posted : 10/07/2019 6:23 pm
nikolai.r
(@nikolai-r)
Noble Member

The only thing I don't like on the higher capacity PSU's is the fan. It's pretty loud and turns on/off all the time.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 10/07/2019 6:41 pm
thaddeus.a
(@thaddeus-a)
Active Member

Huh, not sure why you feel that way, I can't even tell when the fan is on and I work in the same room as the printer. It is plenty quiet to me.

Posted : 10/07/2019 6:43 pm
nikolai.r
(@nikolai-r)
Noble Member

Then maybe let me rephrase it. I can clearly hear once the fan goes on and off. MK3/MK3s is pretty quiet, especially if you print without the part blowing fan.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 10/07/2019 6:46 pm
paul.m27
(@paul-m27)
Honorable Member

I have the meanwell 350 PSU.  I had two failures of my mk3 PSU within the first month and just replaced it (the 3rd prusa PSU is on the shelf).  

I agree on the fan.  It doesn’t run constantly as it is under quite low load, but every few minutes it kicks on for 10 seconds and then off again, quite noticeable over the printer (even in non-stealth mode).  I’m used to it by now, but it still bugs me.  

I noticed my new mk3s has a black metal cased PSU (no plastic parts, braces to the side of the rear extrusion rather than the top.  I’m hoping this means they have a new supplier and I’ll get better luck with it.  If I move it out and design a brace, I’ll have the brace connect to the side: much less likely to collide with the bed.

Posted : 10/07/2019 7:03 pm
guy.k2
(@guy-k2)
Noble Member

On my Meanwell's I replace the fans with 120 mm quiet fans. Barely can hear those at all.

Posted : 10/07/2019 7:18 pm
paul.m27
(@paul-m27)
Honorable Member

I tried to do that, had it all taken apart and everything, and my fans turned out to be slightly to high and hit the board.  I looked at mounting the fan externally, but it was too much of a pain.  

What fan did you use?

 

Posted : 10/07/2019 7:20 pm
thaddeus.a
(@thaddeus-a)
Active Member

I am not sure which one he used, but the standard fan is 25mm thick, high. The normal slim/low-profile fans are 15mm. You could take a look at one of these: https://www.amazon.com/Noctua-NF-A12x15-PWM-premium-quality-quiet/dp/B071W6HJP6/?tag=akshatblog198-20

Posted : 11/07/2019 3:56 am
guy.k2
(@guy-k2)
Noble Member

Not that special of a fan. I had some of the Zalman's left over after swapping them out of some drive towers. Noctuas are quieter, but these Zalmans are so quiet that for a long time I was convinced the fan never came on. I can't see the fans from the front of my enclosure. Then one day I was working in the back and saw the fan spin up.

Mine are attached to outside of Mean Well case. I took a panel nipper and cut out a larger hole for the fan. Drill two holes and the Zalman was readily mounted to the outside.

Posted : 11/07/2019 8:00 am
paul.m27
(@paul-m27)
Honorable Member

Yeah, I considered external mount but didn’t have the motivation, and now I’m sort of used to it.

 

Posted : 11/07/2019 2:32 pm
Robert-mm200
(@robert-rmm200)
Noble Member

Mean well is discontinuing the NES family of PSU units, and recommends the LRS series as replacements.

An advantage to me is that the LRS 350 watt PSU is about 25% cheaper than the NES on Amazon.

Anyone know of any reason to prefer the NES unit at this point?

Posted : 11/07/2019 5:30 pm
thaddeus.a
(@thaddeus-a)
Active Member

In looking at the specs, the LRS looks slightly better overall, and there are a number of good enclosures available on Thingiverse. I can see no good reason to force anyone down the NES path. On the areas where the NES appears slightly better, it is effectively miniscule IMHO. I wasn't aware of the discontinue when I bought mine.

 

Oh, and some enterprising folks have already designed LRS enclosures with the external fan mount included, so you don't even need to drill holes. Like this one: https://www.thingiverse.com/thing:3406054

This post was modified 1 year ago by thaddeus.a
Posted : 11/07/2019 6:14 pm
guy.k2
(@guy-k2)
Noble Member

Both of my Mean Well's are LRS-350-24's

They work well without any fuss.

Posted : 11/07/2019 6:41 pm
Robert-mm200
(@robert-rmm200)
Noble Member

I don't even have my printer yet (arrives next Tuesday), but my LRS 350 arrives tomorrow. Could not pass up that $30 price for what you get.

Good chance I am going to be a parts junky.

 
Posted : 12/07/2019 12:41 am
william.m51
(@william-m51)
Estimable Member
Posted by: thaddeus.a

In looking at the specs, the LRS looks slightly better overall, and there are a number of good enclosures available on Thingiverse. I can see no good reason to force anyone down the NES path. On the areas where the NES appears slightly better, it is effectively miniscule IMHO. I wasn't aware of the discontinue when I bought mine.

 

Oh, and some enterprising folks have already designed LRS enclosures with the external fan mount included, so you don't even need to drill holes. Like this one: https://www.thingiverse.com/thing:3406054

I used one of those on my Mean Well, along with an Arctic F8 Silent fan.  You have to do a little surgery on the fan connector, but it's quieter than the printer when sitting next to me on my desk.  It does run a little longer than the stock fan due to the lower air velocity. 

Posted : 12/07/2019 3:15 am
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