Hi, I’m wondering what the minimum resistance is that can be used on the vertex motherboard?
I assume this is directly linked to the maximum rated current the used N-MOSFET’s for T3 an T4 can deliver? (I’m not that great at electronics so please correct me if I’m wrong!)
The stock delivered heater has a resistance of around 8 Ohm’s I think? (I didn’t disconnect so This could be wrong)
But I just received my E3D chimera kit and those come with 30 watts cartridges @ 12V and have a 5 Ohm resistance.
SO I’m aware these will draw a higher current while heating but could this harm the motherboard Or should it do just fine?
I just want to make sure it’s capable, and I want to use it to reach some higher hotend temperatures than the original is capable of.
Not exactly what I hoped for as an answer tbh.
But T3 and T4 what kind of FET’s are those? Maybe a datasheet available somewhere?
Or is there a component list of the motherboard? Or do you see any other limitations?
Just saying “This cartridge is completely at your own risk” is the easy way to answer…
I mean my doctor doesn’t recommend me smoking… And me smoking goes pretty well for decades…
I know it ain’t good but I’m not instantly blowing a fuse of lighting just one cigarette…
I’m not trying to be rude but some more facts and numbers would be really welcome.
With your values I’d say the original cartridge is sucking 1.9A at 15V. With your E3D it will be 3A. The MosFet should withstand that.
I don’t know for the K8400 (but it should be the same) but with my K8200 I changed a parameter in the firmware (configuration.h) to limit the current to the cartridge :
//#define PID_MAX 255 // limits current to nozzle; 255=full current #define PID_MAX 150 // limits current to nozzle; 255=full current
Then you’ll have to adjust the PID settings and save them in the EEPROM.
Well Raby is correct in saying that the mosfet will probably handle the extra load fine but as a company we cannot support attaching heavier than designed loads on that mosfet ;).
So again it is entirely on your own risk but you can be safe about this: first measure the current draw with the original load and then with your new one. Compare that value with the datasheet of the mosfet and you’ll now if you are in the clear or not.
[quote=“VEL327”]Well Raby is correct in saying that the mosfet will probably handle the extra load fine but as a company we cannot support attaching heavier than designed loads on that mosfet ;).
So again it is entirely on your own risk but you can be safe about this: first measure the current draw with the original load and then with your new one. Compare that value with the datasheet of the mosfet and you’ll now if you are in the clear or not.[/quote]
If anyone wonders what MOSFET’s are used those are BUK6215-75C Datasheet BUK6215-75C
(Spend some time looking for the type so it might be useful for future search reference)
So 15V stock cartridge is 8 Ohms
So Current drawn would be 15/8 = 1,875 Amps
And Risky dangerous and highly contagious E3D cartridge is 5 Ohms
So that would draw a current of 15/5 = 3 Amps
And looking at the data-sheet as a total nitwit I think (PLEASE correct me if I’m wrong)
At a 100°C environment temp (safe side) the maximum current continuous drawn can be 40 Amps at 10 Volt this is 0.25 Ohms as resistance in that case…
SO 0.25 * 15v = 60 Amps???
which is converted to a maximum of 60 Amps at 15 volts???!!!
(Is this correct? I’m doubting my restricted intellect at this point…)
Now… If this is all ‘Kinda’ what I said above… I’m pretty safe to say it totally cant harm the thing… At least if I’m interpreting everything correctly…
The math is not that simple (many parameters are in play) but I agree with you the MosFet can take the 3A needed. You just have to check if the PCB paths can allow that current but they should.
And you still can modify the firmware to limit the current.
So long story short, to avoid the main-board getting any nasty “chronic warranty diseases” from this heater cartridge I’d better use a condom while using it.
############# Hypothetical speaking Could the following twisted idea work??? Generated inside my currently C2H5OH soaked brain… #############
In my (very troubled) head I mean Condom as in isolating the the main-board from the cartridge like this: connecting the Ext1 / Ext2 output to a Optocoupler like the sfh610 and letting that boss around a IRLU8743 style ninja MosFet which connects the Possible “chronic Warranty disease” Heater cartridge straight to the 15V-vdc psu.
Or is this a drunk-man’s idea that can’t work for some real obvious and for me totally ignored reason, and is just fantasy?
If it works for the bed it will also for the heater. But imho it’s not necessary.
Last answer from Vel327 means for me : it will work but if something goes awry don’t complaint. But it’s also true for any other manipulation like inserting a power expander and your board is blowing up because you connected something the wrong way.
Yeah well… Turning the thing on is at your own risk tbh… Example 1: on day 1 in school 16 years ago when we started to wire our first wall sockets and plugs they told me to ALWAYS make the ground wire longer than the neutral and the hot wire… Not the case with the presoldered cable… Just saying it’s pretty lame to say “whatever it’s not ours, so your totally on your own” when I just asked for some pretty simple numbers to make sure… Not for a warning campaign about how bad and unsupported other components could be… The first answer of vel327 should’ve been. “” Look at the BUK6215-75C datasheet for more information about the switching characteristics the Mosfet has. And of course be careful not to damage anything, your warranty on the mainboard might end doing so. Have a nice day and maybe share some more details about how your trying to mount that sweet chimera head. “”
Did I go overboard on this one?
something totally else
@Velleman forum/server admin I just got a “general error” sql error [ mysqli ] while posting this msg (check logs) which shouldn’t be shown imho and indicates u guys are using utf8_unicode_ci or something like that for the post_text column in the posts table.
I’d suggest to do something in this fashion so it won’t trip over it anymore.
ALTER TABLE phpbb_posts CHANGE post_text post_text MEDIUMTEXT CHARACTER SET utf8 COLLATE utf8_bin NOT NULL
Disabling error reporting in production environments is also a good idea.
Set error_reporting(0); value in one if your phpbb header files to disable leaking useful Intel about abusable data.
What caused it?? Well adding a smiley into this message on Android causes it to send F0 character that’s unsupported in utf8.
[quote=“jeafke”]Yeah well… Turning the thing on is at your own risk tbh… Example 1: on day 1 in school 16 years ago when we started to wire our first wall sockets and plugs they told me to ALWAYS make the ground wire longer than the neutral and the hot wire… Not the case with the presoldered cable… Just saying it’s pretty lame to say “whatever it’s not ours, so your totally on your own” when I just asked for some pretty simple numbers to make sure… Not for a warning campaign about how bad and unsupported other components could be… The first answer of vel327 should’ve been. “” Look at the BUK6215-75C datasheet for more information about the switching characteristics the Mosfet has. And of course be careful not to damage anything, your warranty on the mainboard might end doing so. Have a nice day and maybe share some more details about how your trying to mount that sweet chimera head. “”
Did I go overboard on this one?
something totally else
@Velleman forum/server admin I just got a “general error” sql error [ mysqli ] while posting this msg (check logs) which shouldn’t be shown imho and indicates u guys are using utf8_unicode_ci or something like that for the post_text column in the posts table.
I’d suggest to do something in this fashion so it won’t trip over it anymore.
ALTER TABLE phpbb_posts CHANGE post_text post_text MEDIUMTEXT CHARACTER SET utf8 COLLATE utf8_bin NOT NULL
Disabling error reporting in production environments is also a good idea.
Set error_reporting(0); value in one if your phpbb header files to disable leaking useful Intel about abusable data.
What caused it?? Well adding a smiley into this message on Android causes it to send F0 character that’s unsupported in utf8.
