Additional power supply for heatbed

Got my setup working now, and damn it heats up quick. Also reaching 100 C is a first … will make printing ABS a whole lot simpler.

Regarding powering the main board through a HCJ-IPM-V2; well, it only partially worked. Heating the extruder to 220 C and moving around X and Y axis at the same time worked fine with a current of approximately 2,6 A, making the unit get quite hot (but not scorching hot). As soon as Z axis movement was added though, and the stepper started grinding, the regulator failed and the printer brown out:ed. It might be possible to add a beefy capacitor after the unit to compensate for the Z steppers gluttonous needs, but for now I just keep the original supply in tandem with the 24 V one for the heat bed.

A small bump on this thread.

When ordering a new heatbed I noted that at least reprap.me has a ready made power expander circuit for sale. I haven’t got a clue how it looks or performs, but it seems like it’s more or less the same as our home made circuits. Could be an alternative for people not comfortable building the coupler-mosfet circuit for themselves.

[quote=“magu”]A small bump on this thread.

When ordering a new heatbed I noted that at least reprap.me has a ready made power expander circuit for sale. I haven’t got a clue how it looks or performs, but it seems like it’s more or less the same as our home made circuits. Could be an alternative for people not comfortable building the coupler-mosfet circuit for themselves.[/quote]
Thanks for this update. I’m really considering to order it. It’s not that expensive… Which power supply are most people using? I’ll still have to order that

This is what i have ordered.
reichelt.de/index.html?&ACTION=446&LA=446

[quote=“2stimpy”]This is what i have ordered.
reichelt.de/index.html?&ACTION=446&LA=446[/quote]
Thanks for the respons but the link does not work

Oh, sorry.
maybe now.
reichelt.de/Schaltnetzteile- … T+MW100-24

On page 4 of this post, you have ALL links and stuff needed for the additional power supply.
Just read and enjoy

[quote=“2stimpy”]Oh, sorry.
maybe now.
reichelt.de/Schaltnetzteile- … T+MW100-24[/quote]
Since I like being overpowered, and not having to bother with cooling the supply, I bought this: SNT MW-SP320-24 :: Switching power supply, closed, 24V / 13A / 320W

I e-mailed them about the ready-made mosfet controller once I read about it here on the forum. I asked for a picture and more info on the size etc… Still no answer. I could risk it and just order it, but not getting feedback makes me worry about the service :-/

I ordered a heated bed and they sent it the same day, so the service doesn’t seem all too sloppy.

I am now waiting for the bed t reach 110c, i have been sitting here now for 30 minutes and its at 103c.
I doubt if i reach the 110c.

So i need to upgrade the bed even more with a new heated plate, and a new power supply.
This simply can’t handle the job.

[quote=“2stimpy”]I am now waiting for the bed t reach 110c, i have been sitting here now for 30 minutes and its at 103c.
I doubt if i reach the 110c.

So i need to upgrade the bed even more with a new heated plate, and a new power supply.
This simply can’t handle the job.[/quote]
Are you using the 100 W MeanWell supply? I get my stock K8200 bed up to at least 115 C with my 320 W supply on 24 V (in a cabinet). You might be maxing out the supply.

Changing the PCB bed to one with proper support for 24 V will of course make it easier to reach higher temps. Even more so by getting the M3a alu bed and using the 12 V terminals with 24 V (as instructed by the supplier); which supposedly makes it possible to reach more than 100 C in about 2 minutes.

Hi magu,

the cabinet is probably the important part there, since it reduces airflow and thus also the loss of heat.

Second option: you got a heatbed with low resistance, which would result in a couple of watts more heating power. Did you measure the resistance? Here it’s 5.7 Ω at room temperature.

Cheers,
kuraasu

[quote=“kuraasu”] Did you measure the resistance? Here it’s 5.7 Ω at room temperature.
[/quote]
I’ve just received my Mk3 alu bed and plan on installing it next week. Can measure the resistance on the old one by then.

I ordered the mosfet from Reprap.me, once i receive it ill post it here

[quote=“magu”][quote=“2stimpy”]I am now waiting for the bed t reach 110c, i have been sitting here now for 30 minutes and its at 103c.
I doubt if i reach the 110c.

So i need to upgrade the bed even more with a new heated plate, and a new power supply.
This simply can’t handle the job.[/quote]
Are you using the 100 W MeanWell supply? I get my stock K8200 bed up to at least 115 C with my 320 W supply on 24 V (in a cabinet). You might be maxing out the supply.

Changing the PCB bed to one with proper support for 24 V will of course make it easier to reach higher temps. Even more so by getting the M3a alu bed and using the 12 V terminals with 24 V (as instructed by the supplier); which supposedly makes it possible to reach more than 100 C in about 2 minutes.[/quote]

Jip, using the 100 w power supply.
I am also thinking about installing a new heatbed, but i think this also means buying a new power supply because than 4,5 amp is not enough i think.
As you can see in my other post, i also have my printer in a box.(still need to fit the door though.

I have been searching for info on the power supply needed for the MK3 heatbed.
My knowledge on electronics does not reach that far.
Will it work if i use my 100w 4,5 amp 24v power supply on this heatbed and benefit faster heating!

Hi 2stimpy,

just to be sure - you are talking about the Mk3 dual power alu heatbed, right?

100 W is not enough either way. In the 24 V connection scheme, the bed has (depending on its actual resistance) around 100 to 120 W heating power. You should add a few percent to that value though, so that the supply does not run at 100% output all the time.

Using 24 V on the 12 V terminals gives a factor of four for the power, so either more than 400 W are needed, or a power supply that is truly and permanently short-circuit proof (apart from a relay that can handle the current).

Cheers,
kuraasu

It is indeed the dual power mk3 heatbed.
I am going to look for an other power supply than. I do want to use the maximum out of it.
Now i have to wait 25 minutes for the heatbed to reach 100 degrees, it doesn’t even reach 110.

I understand that i also have to find a solution for the switch/relais, because the print i made from the schematic earlier in this topic wont do the job.

But if there is a need of bigger switch and bigger power supply, than i also should use thicker wires i think.
I dont think the standard ribbon cable can handle the higher currents.

Something like this should be able to do the job i think.
ebay.com/itm/GRS-24V-20A-500 … 1140986031

or this

ebay.com/itm/480W-24V-20A-Re … 1435666711

2stimpy, how did mount the mk3 heat bed on K8200?