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Converting 12v to 24v

Posted by Cougar281 
Converting 12v to 24v
January 03, 2018 10:28AM
I would like to upgrade my printer from 12v to 24v, as the 12v power supply pretty much struggles when the bed heater is used, even the 14Ga feed cable I used gets a bit warm, and from what I've read, due to the decreased current, 24v is better for the controller. I know the bed can be set up either way, I would just need to change it from the 12v wiring to 24v. The fan, which runs all the time as it's cooling the throat(s), I'd need to either replace with a 24v one or I could probably use an appropriately sized resistor to cut the current down to it. The controller states 12-24v input, so I assume that it has one or more voltage regulators onboard for all the low voltage/low current devices - I'm assuming the steppers and other low current devices probably run off 5v. The only thing I'm not sure of is the heaters for the hot ends. The hot ends are, from what I can tell, Mk8 hotends, but I haven't found anything really clear on the heaters for them. I'm assuming I'd have to change them out? Anything I'm missing?

Any tips?

Edited 1 time(s). Last edit at 01/03/2018 12:27PM by Cougar281.
Re: Converting 12v to 24v
January 03, 2018 07:49PM
You don't use a resistor to drop 1/2 the voltage, it has to turn half the power into heat.....

The stepper motors we use are generally ok with 12v or 24v the stepper drivers are 5v. But standard drivers and steppers are fine with either VMOT voltage.

fans should be 24v or use some 7812 to drop the voltage.

the hot end is also 12v, you need to swap the heating cartridge for a 24v version. (high current, not so easy to drop the voltage)

and yea heated bed needs to be switched to 24v mode.

Any fancy leds will also have to be looked into... may be running on 12v

LCD is 5v and will be fine.
Re: Converting 12v to 24v
January 04, 2018 12:32AM
Converting a bed heater to 24V because the 12V PSU struggles, only makes sense when the 24V PSU is stronger. Because the power consumption will be the same. It will be more gentle on the wires and board terminals.
Re: Converting 12v to 24v
January 04, 2018 04:19AM
Yes, in terms of Watts, 12v & 24v use the same power, but due to the increased voltage, the current is lower, thus it's easier on the components (less heat for the high draw circuits except where you want the heat). I ordered a PSU that is 24v/20A/480W, which is twice what the 12v/20A/240W one that came with the kit is rated at. The 12v definitely struggles when the heater turns on - there's a noticeable drop in the speed of the fan cooling the throats whenever the bed heater turns on (That fan is wired directly to the supply and is on whenever the PSU is on). The 24v supply should be much leas loaded than the 12v one.

Edited 1 time(s). Last edit at 01/04/2018 04:20AM by Cougar281.
Re: Converting 12v to 24v
January 04, 2018 07:03PM
How about use two power supplies keep the 12 volt one and move just the heat bed to it's own 24 volt one.


Newbie with Folgertech 2020 i3.
Re: Converting 12v to 24v
January 05, 2018 09:49AM
why cant you get a higher amp 12v p/s to cope with the heat bed instead of changing everything to 24v!!
Re: Converting 12v to 24v
January 05, 2018 05:21PM
Quote
Thereaper
why cant you get a higher amp 12v p/s to cope with the heat bed instead of changing everything to 24v!!

That doesn't help the fact that the current associated with the 12v setup is harsher on the components of the controller (generates more heat) and with this controller in particular, from what I've read, is responsible for melting and cooking things (The wire supplied connected to the bed heater gets quite a bit warmer than I like with the 12v current, and even the 14Ga wiring that I had and used for the main feed gets a little warm to the touch - the 16 or 18Ga wire they supplied intended for the main feed? Forget it with everything on, it probably would have burst into flames - I'll be replacing both with 12Ga wiring in addition to upping to the 24V supply - they shouldn't get warm after that)... plus the PSU is the most expensive individual part. Why would I buy another, higher amperage/wattage 12v PSU (say 12v/40A/480W), that isn't that far off in cost form the 24V/20A/480W and doesn't alleviate any stress on the FETs and connectors on the controller? The 24v 480W PSU was a few dollars more than a 12V 480W one, and the heaters for the hot ends (four of them, so I have a few spares) plus a 24v fan were like $10. There are multiple ways to do it, but in the end, reducing the current is how you relieve stress on the controllers components. Whether that's from switching to 24v or a beefier 12v supply and adding an external high-current FET based controller for the bed.

Edited 1 time(s). Last edit at 01/05/2018 05:21PM by Cougar281.
Re: Converting 12v to 24v
January 06, 2018 09:27AM
Most of the time what fails is the heat bed connector, not the wires or the FET.

ANyway, for new designs 24V is better. To have the bed mains powered is great but requires a lot more care due to security concern.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: Converting 12v to 24v
January 09, 2018 05:36PM
Welp, rather glad I decided to upgrade it to 24v and had ordered the required parts last week - after the bed had heated and the nozzle was heating for a print, the 12v PS died with a few pops and a whiff of 'magic smoke'. Didn't think it had it in it and it was getting a 'tad' warm on some longer prints. Oh well lol. I wonder if they put the wrong one in the kit? The bed heater was an upgrade and this 240W PS would be fine for just the extruders with no bed heater.
Re: Converting 12v to 24v
January 09, 2018 06:54PM
I still have the original 12V 250W Power supply connected to My 3D Printer. However if did pop an a 250W Billow of foul smelling smoke came out.
I dissembled the power supply and determined that they had a 3amp fuse in series with a thermal resistor fuse. And the thermal resistor fuse had split in half.
Checking specs on the thermal resistor fuse found it was under rated for the power supply wattage. And with a 3 amp fuse in series with a thermal resistor fuse was a redundancy.
So removed the thermal resistor fuse replacing it with a bare wire, have been running the 12v 250w supply in the 3D Printer now on 1 1/2 years with no problems.

By the way did purchase a 24V 360W Power Supply just in case the 12V supply failed.
3D Printed a cover for the terminal strip with an power Switch, 120V Power connector, and a 24v - 12v Led dimmer control for T-Slot Led lighting Strips.

Never throw any thing away unless it can not be fixed for less than a new replacement.
Re: Converting 12v to 24v
January 11, 2018 04:30PM
The last two days I spent a little time each day swapping out what I had to for 24V and re-wiring the bed heater and cleaning it all up, and the 24v PSU arrived today. I have to say I'm quite happy with the upgrade. With the 12v PSU, the main 14Ga feed would get a little warm, the bed heater wires got what I felt was uncomfortably warm, the lexan that the controller is mounted to would get quite noticeably warm under the FETs, and the heatsink on the bed FET (possibly the nozzle heater FET as well, never really felt that one) would get really toasty and the PSU got REALLY REALLY toasty (Maybe that's what killed it). With 24v, the FETs are barely warm to the touch, if warm at all and the PSU doesn't even get a little warm (doesn't hurt that it has its own cooling fan). The wiring wiring doesn't get hot either, but now it probably wouldn't even with 12V because I upgraded it to 12Ga wiring. I feel a lot better about the safety and operation of this printer now that the only parts that are getting hot are the ones that are SUPPOSED to. Really wasn't wild about how hot some of the parts that really aren't supposed to get hot were getting.

Edited 1 time(s). Last edit at 01/11/2018 04:44PM by Cougar281.
Re: Converting 12v to 24v
January 12, 2018 12:54AM
What about the noise of the steppers? They are quiet now?
Re: Converting 12v to 24v
January 12, 2018 06:43AM
What noise are you referring to? I've read some posts about steppers making annoying high pitched noise when idle but powered, which these don't make, but they do make 'noise' when they're moving, although I'd say it's nothing annoying and is a 'noise' that I'd consider normal for operating motors. Plus the supply voltage shouldn't make a difference to them, as best I can tell, they seem to actually run off 3.3v or 5v, so a voltage regulator on the controller would be knocking the input voltage down to what they need.
Re: Converting 12v to 24v
January 13, 2018 01:18AM
Quote
Cougar281
What noise are you referring to? I've read some posts about steppers making annoying high pitched noise when idle but powered, which these don't make, but they do make 'noise' when they're moving, although I'd say it's nothing annoying and is a 'noise' that I'd consider normal for operating motors. Plus the supply voltage shouldn't make a difference to them, as best I can tell, they seem to actually run off 3.3v or 5v, so a voltage regulator on the controller would be knocking the input voltage down to what they need.

Stepper don't run at 3.3V or 5V, the drivers are current source. 24 V power supply does make a difference, the motor are more "responsive", better acceleration, deceleration ....


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: Converting 12v to 24v
January 13, 2018 12:46PM
You sure? This is the stepper on my X & Y axis (Z might be the same), and according to the page, it's 3.3V. I haven't been able to find anything to indicate that they run on 12 or 24v, but I've seen 3.3v multiple places for these particular steppers. I can't say I noticed any apparent difference in their operation after switching to 24v. If there is some difference that I'm just not noticing, would the switch need some change to the firmware for them?

Edited 1 time(s). Last edit at 01/13/2018 12:47PM by Cougar281.
Re: Converting 12v to 24v
January 13, 2018 01:38PM
Have a look at the driver datasheet: [www.allegromicro.com]


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: Converting 12v to 24v
January 13, 2018 06:10PM
That suggests to me that the driver is capable of running up to 35v, not necessarily that the steppers are running at that voltage (or whatever the board input voltage is).

At any rate, whether they run at 3.3v, 5v, 12v, 24v, or whatever, the drivers are fine with whatever the voltage is supplied to the controller, be it 12v or 24v, and at least in the case of the steppers that are on my printer, I don't notice any difference in them, acoustically or otherwise. The only things I noticed with the swap is no brownouts when the bed heater kicks in and pretty much no heat where it doesn't belong (and MAYBE faster heating - not really sure on that one), which is what I was aiming for. The only thing that's still getting a bit toasty are the stepper drivers (I'll have to get some tiny heatsinks), but they are probably the same as before (or maybe less if the steppers really were running 12v and now are 24v), and no where near as hot as the Bed, and maybe nozzle FETs were getting. Like I said, I'm quite happy with the swap, and if anyone is thinking about it, I'd say go for it (provided your controller will support it and you change or reconfigure what you need to for 24v). I don't think you'll be unhappy with it.
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