How to Upgrade to 24V



  • Hey there,

    I think about upgrading my printer (using a Duet Wifi) with a new PSU.
    There are three main reasons for this:

    1. 24V for better power failure support
    2. Remote on/off using Web Control
    3. 24V component compatibility

    The problem is that there seem to be no 24V PSUs which support the ATX style power switch wiring and a consistent 5V supply.
    Additionally I am still using 12V hardware (heated bed, hotend, probe, fans, stepper motors) only.

    Is there a way to use a 24V PSU while still powering the components with 12V and eventuelly switching to 24V for single components when they get replaced by 24V equivalents? The heated bed should be no problem at all, since it is already using a mosfet.
    How can I use the Duet Wifi to turn the 24V circuit on and off? I might use USB to keep the 5V circuit on but how should I wire the PSU to be able to turn ist on and off using Web Control?

    Thanks in advance!
    GaRv3



  • I highly recommend the Meanwell HLG series supplies.

    I use the HLG-600H-24, fanless, 25A at 24V, constant 5V standby supply and remote on/off for the 24V. But they make a range of different wattages.

    I run a 24V 18A heatbed and 2A steppers with the duet. Even after a 12 hr print the supply is barely warm.

    They aren't cheap but they are well made and noiseless.

    There is one problem, the remote on/off is opposite polarity to the Duet. I use an optocoupler with and inverting output to fix this.



  • @insertnamehere said in How to Upgrade to 24V:

    HLG-600H-24

    The HLG-600H-24 seems to be great.
    But is it possible to run 12V components connected to the Duet using a 24V PSU? If not, I would have to change all components to 24V at once.



  • @garv3 said in How to Upgrade to 24V:

    @insertnamehere said in How to Upgrade to 24V:

    HLG-600H-24

    The HLG-600H-24 seems to be great.
    But is it possible to run 12V components connected to the Duet using a 24V PSU? If not, I would have to change all components to 24V at once.

    Just add a step-down converter. This works good for fans by connecting it to V_FAN pin on Duet



  • Thanks. Sounds like a valid option!



  • I can't help with which PSU. I'm using a cheap one that doesn't have remote-on, or a 5V supply.

    I am running some 12V fans. A buck-boost converter will provide 12V which can be used for fans or other lowish power devices. Mine provides up to 60W (5A) so it's fairly robust. It could probably handle the hot-end as well as fans, but certainly not the heated bed.

    I saw a huge improvement going to a 24V heated bed. It reaches temperature so much faster. Lots of people say the same again about going to a mains powered bed heater. The hot ends see to be similar wattage in either 12V or 24V, they still seem to be about 40W. Some of the 24V ones are 50W, but those changes are relatively small.

    The stepper motors can stay the same. The only major change seems to be with running two Z motors in series, where 24V has more headroom to supply the needed current. The higher voltage also seems to effect higher maximum speeds.

    You might find, though that your best upgrade will be going to a mains powered bed heater with an SSR.



  • Okay, so there is no way to power the Duet with 24V and get 12V out of it directly for defined ports, right?

    This means, if I use 24V+5V for the Duet, mains power for the heated bed, some 24V fans but a 12V Hotend with a 12V fan, I will have to use regulators for all 12V components and an SSR for the heated bed.

    I dont's know much about SSRs. As far as I know these are electronic relais without mechanical parts, so they should not produce any clicking noise and the delay should be very low, right? If so, this would actually be a good way to do this. What is the difference compared to a mosfet like the ones we use for our 12V724V heated beds?



  • @garv3 That pretty much sums it up and is what I use. Mains bed via SSR (Solid State Relay) then 24 to 12V DC converter for the fans. Connect the plus side of the fans to the 12V DC output from the converter but connect the negative side of the fans to the Duet, then you can use PWM to control the fans. TBH, heater cartridges are cheap as chips so I simply use a 24V cartridge rather than run the heater off 12V.

    Edit. The Duex 5 and Duex 2 expansion boards have 12V for fans but that would be an expensive way of getting the 12V you need, unless you have a need for the additional expansion capabilities.



  • @garv3 said in How to Upgrade to 24V:

    This means, if I use 24V+5V for the Duet, mains power for the heated bed, some 24V fans but a 12V Hotend with a 12V fan, I will have to use regulators for all 12V components and an SSR for the heated bed.

    I would use a 24V hotend, as it draws much power (30-40W?).
    Note that a DCDC would have to deliver at least 12V/3A just for the hotend, and would convert another ~20-30% into heat (about 6-9W if i'm correct) while doing its job.



  • @phantomix said in How to Upgrade to 24V:

    I would use a 24V hotend, as it draws much power (30-40W?).

    40W 12V heater uses the same power as 40W 24V... well both are 40W -_-
    You mean probably current? In general running a heater from stepdown converter is generally not a good idea. 24V heaters are super heap, not worth the hassle.



  • Of course is 40W = 40W. The question is if you need to convert 24V to 12V first (which would result in a very beefy DCDC buck regulator). For 40W this would mean also a lot of heat produced in the regulator itself.

    40W @12V means 3,33A. PLUS about 10W ("DCDC efficiency" is the point here, around 70-90% depending on the part)
    40W @24V = 1.67A



  • If you are going to use a 12V hot end, and use a mains powered bed heater, I would just leave Vin at 12V. The heated bed is the biggest advantage of 24V over 12V, and if you're going SSR/Mains power for that, there aren't nearly so many reasons to upgrade at that point.

    The hotend at 24V is an advantage if you want a 50W or 60W hotend, but for 40W, it really doesn't matter that much. 12V fans are cheaper and more reliable.

    24V does give you some advantages with the motors, if you are unable to get full speed/torque with 12V. This isn't likely to be much of a problem, though I could see it with 2 Z motors in series possibly being current limited for speed, but fast Z motion isn't usually needed as much.



  • @supraguy said in How to Upgrade to 24V:

    If you are going to use a 12V hot end, and use a mains powered bed heater, I would just leave Vin at 12V. The heated bed is the biggest advantage of 24V over 12V, and if you're going SSR/Mains power for that, there aren't nearly so many reasons to upgrade at that point.

    Biggest advantage of 24V is higher max speed and torque on stepper motors. And they run quieter
    I am having mains powered bed and running 24V only for that :P. But I agree 24V -> 24V hotend


 

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