Power supply Upgrade for faster heating  

Re: Power supply Upgrade for faster heating

What is your PSU output voltage? Did you know you can adjust it a bit using trimpot inside the PSU?

Re: Power supply Upgrade for faster heating

Hi Murathan,
could you elevate the room temperature? that will speed the bed heating.

the Mk2 power supply has a trimmer resistor under the bottom plastic cover,
if you test the voltage, and it's at or below 12 volts when trying to heat the bed, you could consider easing the voltage up a little... I am no expert, perhaps 12.5 volts...

others say they have gone higher...

mine is about 12.5 volts

regards Joan

Re: Power supply Upgrade for faster heating

Room temperature is about 23-24 degrees and the printer is just 20cm away of the heater block.

I know that modification but did not want to try if it may damage the rambo board. 0.5v wont make a big difference I guess but I should measure the voltage first. Maybe mine is below 12v. Let me see first.

What is the maximum safe voltage, any idea?

Re: Power supply Upgrade for faster heating

Hi Murathan,

the Rambo Mini information page is at
https://ultimachine.com/products/mini-rambo-1-3 or
http://reprap.org/wiki/MiniRambo

probably the most important features are :-
Power
2 power input rails
Heated Bed, 15A 12-35V
Primary Power 10A 12-28V: Motors (5A dedicated fuse) + Extruders, Fans, & Logic (5A dedicated fuse)
Built in SMPS for 5V generation from Extruders + fans and logic

So I expect the limiting factors will be the current drawn by the extruder heater and the heat bed... as they are the primary load on the fuses.

the stepper motors are managed by the motor controllers so you don't have to worry a lot about the voltage for them.

the fans are probably rated to 13.8 volts
regards Joan

Re: Power supply Upgrade for faster heating

There is another option. Using this http://www.banggood.com/3D-Printer-Parts-General-Add-on-Heated-Bed-Power-Expansion-Module-High-Power-For-Chitu-Motherboard-p-1086965.html you can experiment with different voltages and currents with no risk of damage to RAMBo. But it requires a bit of electrical knowlegde and experience.

Re: Power supply Upgrade for faster heating

hey many thanks for this information. I will get this item. But what do you mean by electrical knowledge? all I have to do is connect this lttle board between rambo and heatbed right?

Cheaper in aliexpress btw

https://www.aliexpress.com/item/New-Electric-Board-for-3D-Printer-General-Add-on-Heated-Bed-Power-Expansion-Module-High-Power/32716300027.html?spm=2114.01010208.3.1.OBFn8e&ws_ab_test=searchweb0_0,searchweb201602_2_10065_10068_10000009_10000032_10084_10000025_10083_10080_10000029_10082_10081_10000028_10110_10111_10112_10060_10113_10114_10062_10115_10056_10037_10055_10054_10059_10032_10000044_10099_10078_10079_10000022_10077_10000012_429_10103_10073_10000015_10102_10096_10000035_10000018_10000019_10052_10053_10050_10107_10051_10106-10050,searchweb201603_1,afswitch_2,single_sort_3_price_asc&btsid=84695da6-996b-4031-b8af-ef36d56863f4

There is another option. Using this http://www.banggood.com/3D-Printer-Parts-General-Add-on-Heated-Bed-Power-Expansion-Module-High-Power-For-Chitu-Motherboard-p-1086965.html you can experiment with different voltages and currents with no risk of damage to RAMBo. But it requires a bit of electrical knowlegde and experience.

Re: Power supply Upgrade for faster heating

But what do you mean by electrical knowledge?
Ohm's law should be enough for a start. 😉

Re: Power supply Upgrade for faster heating

😀

Is this module for increasing the power going to the bed or just a protection module for increasing voltage from psu?

Re: Power supply Upgrade for faster heating

Is this module for increasing the power going to the bed or just a protection module for increasing voltage from psu?
I think the reason that module has been developed is to divert high heatbed currents out of control board to protect its connectors from burning out. The bonus is that you can simply use 24V for bed heating and still leave board, motors and hotend at 12V, because with that module you can use independent PSU for heatbed. Of course you need 24V heatbed for that.

Re: Power supply Upgrade for faster heating

now I am totally lost david:(

If I connect this board between my MK42 bed and the rambo board, without increasing the power output of the PSU, my heatbed going to recieve 24v?

Is this right?

Re: Power supply Upgrade for faster heating

Murathan,

No, all this board does is take the current flow to the heatbed from the power supply instead of from the Rambo. It does not increase the voltage to the heatbed.

Re: Power supply Upgrade for faster heating

So the bed will be allways on and heat up to maximum temperature without the control of the thermostat.
This will melt the pei sheet right?

I am not an engineer but this is out of logic, What is it I am missing?

Thank you in advanced

Re: Power supply Upgrade for faster heating

No, it is only external switching device.
You have to connect PSU power to the board, connect heatbed to the board and connect RAMBo heatbed output to the board. RAMBo tells "on" or "off" and the board does the rest. All power from PSU to the heatbed goes outside the RAMBo.

This scheme allows you to use another PSU for heatbed only and experiment with different voltage without risk of damaging anything else. You still have to use original 12V PSU for powering RAMBo, motors and hotend.

Understanding this is exactly that level of electrical knowledge and experience I was talking about.

Re: Power supply Upgrade for faster heating

I am so sorry that I have just recognised the white connector on the board. I have that kind of knowledge but couldnt figure out the logic without a controller. My bad....

Thank you for your patience 😀

Re: Power supply Upgrade for faster heating

Hi Murathan,

be careful with the bed, I have just seen the replacement cost, £74.21 GBP...

regards Joan

Re: Power supply Upgrade for faster heating

Does anyone know what the total 12V power output limit of the stock power supply of the Original Prusa i3 MK2 is?

Re: Power supply Upgrade for faster heating

Hi Murathan,

be careful with the bed, I have just seen the replacement cost, £74.21 GBP...

regards Joan

Thank you joan, thats why I am making a deep research try to learn from scratch. When I am done, I am going to share it with you guys.

Re: Power supply Upgrade for faster heating

Does anyone know what the total 12V power output limit of the stock power supply of the Original Prusa i3 MK2 is?

20 Amps. More than enough to properly power all connected items, with plenty to spare.

Feeding the bed from a separate PSU will make no difference unless the voltage is increased, which can safely be done with the original PSU.

The only advantage with having a separate PSU is that you can increase the voltage to significantly more than the rating of the heated bed. Which will more than likely result in damage, beit warping through to burned out copper tracks. Really, something that I would consider a very bad idea.

I really don't see waiting a few minutes for the bed to warm up as a huge issue, especially when the prints take so long.

Peter

Re: Power supply Upgrade for faster heating

You are right, I agree that the heating time is just an ear of a camel.

I ordered that little external module and and going to connect Power directly from PSU to heatbed with this module. Rest will be same. No need to increase the voltage from PSU in this scenario. With this method heatbed is heating %50 faster without any other modification.

what dou you think Peter?