PS for (full) 24V conversion

Hey there,

I am currently using two power supplies in my printer

1. 12V 200W - for board (SKR1.3), 6x drivers (TMC2209), steppers (17HS4401S) and LEDs (which run on a buck converter 5V @5A max)

2. 24V 480W - for 2x40W heater cartrige and 360W silicone heater

I now consider bringing the full machine to 24V
I figured this should work, I'd just have to swap the 12 fams for 24V ones and get an new power supply, correct?

So my question is how much watts should the ps have? Bc I know 200W works for board+drivers+steppers+led but do they really use 16A?

-Heaters and heatbed are a max of 18.5A together
-Steppers are rated for 1.5A each which would be a max of 9A (which will never be used realistically but still)
-Drivers are rated for like 2A or more but this is the current that is used by the steppers anyway isn't it?
-LED would be max of 25W -> ~1A @24V
-4 Fans are <1A all together
This would be 30A (720W) up untill here on the safe side IMO
How much current does the board use tho?

So I just wanted to double check my calculations here and be sure I am not missing anything AND get some advice on which PS to buy for that project (wattage and brand (meanwell??))
And if it is even feasable getting a single PS with that high wattage in a similar form factor to the usual switching PS that is still affordable

Thanks in advance for your help

You will need to exchange all heating elements since they would havevt twice the power at 24v. Also all fans need 12 v and you would need to check if the leds can work with both voltages. It is not as easy as you might think.

---

[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Quote
Srek
You will need to exchange all heating elements since they would havevt twice the power at 24v. Also all fans need 12 v and you would need to check if the leds can work with both voltages. It is not as easy as you might think.

I think you misunderstood me.
I already run 24V heater cartriges and heatbed
I know that I would have to use 24V capable fans (yes they exist)
Leds are running on 5V already via a buck converter and yes the buck cinverttis also capable of 24V input

Oh and by the way the heating elements on 24V don't have twice the power since 40W equals 40W. The thing that is doubled is the voltage.

It wasn't clear from the inital posting that you exchanged the heating elements. If you hadn't the power consumption of them would have doubled when switching to 24v.
While the stepper motors have a peak current of 1.5 A that is never ever used. Most likely they run below 0.8A. You can get the exact value by measuring Vref and checking the table for your drivers.
The board itself usually doesn't need much, realistically 1-2 A is likely to much.
I have a couple of 24V printers running that i built, i use 400W Nunus PSUs in all of them. They come with an MKIII heated bed and two extruders.
I am a bit surprised that you use such a high powered low voltage heatbed. At that consumption i would go for high voltage AC heating.

---

[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

I believe that your single 24V 480W PSU should be adequate. The rest of hte stuff should be okay on the 40W of headroom that you have, (360W + 40W + 40W = 440W) So long as the 480W rating on the PSU is reliable, and your heaters aren't rounding down too much. Most of them round up. I'll also echo that it seems like a lot of power for a DC heat bed. I'd expect that to be AC powered via SSR.

Also, doubling voltage quadruples power consumption, not double.

If your board will handle 24V power, it's very nice. Faster movement, and better skip rejection. Upgrading to 24V is a decision that I never regret.

BTW, you CAN use 12V fans, but you need to put a resister in-line with the fan or approximately equal to the DC resistance of the fan. I had a bunch of 2W resistors lying around, but I can't remember what value I used, I might have needed a different value for the part cooling fan than for the heat break fan, and I purposely used a slightly higher value for the 80mm PSU cooling fan to slow (and quiet) it some.