Huh. That doesn’t match the schematics or my experience but if you have the N-Channel MOSFET driver module, give it a try.
Hm the printer.cfg looks wild but not bad for that issue here.
As written on the vendors page the heat bed gives you 320 W of heating power.
On that 24 V system it would draw ~13.3 A under full load (without any losses and stuff here).
If the Manta limits that to only 10 A you have about 80 W less heating power, what is about 1/4 if I’m not totally off. 
That has two meanings for you:
- it takes at least about 1/4 longer to reach the same temperature than with the discrete MosFET
- you are overloading the Mantas MosFET and might kill it over time
So I would suggest using the separate MosFET again.
However it is strange when that requires the same heating time as with the Manta.
You might add the following to the [heater_bed] section though its a default if omitted:
max_power: 1.0
If the thermistor is wrong at least the real temperature is different to the displayed one. And if the real temperature is higher than the displayed one, the heating process should take even longer as it is harder for the weak bed to get even hotter - the temperature curve flattens the higher it gets.
The right thermistor should give you the room temperature while the bed is off and cold. So you could check that pretty easy.
Test this with your current config and if its off too far you might check with the one from my post above - copied from the Elegoo firmware files.
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Hm the printer.cfg looks wild but not bad for that issue here.
what is wild? it is the standard layout i got when i first started my printer.
- it takes at least about 1/4 longer to reach the same temperature than with the discrete MosFET
yes, that is true, i was thinking and i remember timing the stock version and it was about 12 minutes, not 10 i rounded that down in my head.
And now it is 15 minutes, 125%
So I would suggest using the separate MosFET again.
I was already doing some reasearh and making plans!
However it is strange when that requires the same heating time as with the Manta.
How did you come to this conclusion?
I thought you mentioned it somewhere above that you tested the Manta with the Mosfet and it was the same?!
But good if I’m wrong here.
As said: with that bed you can’t expect better heating times than with the original stock setup.
Manta has no way of measuring or limiting the bed current to 10A. There is 15A fuse at the input, the mosfet itself will not saturate until way above that with V_gs=5V (it could do over 300A with sufficient cooling)
My suggestion would be to carefully measure voltages while the bed is running 100% at the Manta lugs, both at the bed power supply input to manta and bed output lugs.
I thought you mentioned it somewhere above that you tested the Manta with the Mosfet and it was the same?!
But good if I’m wrong here
nope, never did that, it is something i am considering to do
Manta has no way of measuring or limiting the bed current to 10A. There is 15A fuse at the input, the mosfet itself will not saturate until way above that with V_gs=5V (it could do over 300A with sufficient cooling)
mhm, okay. But strange that they say that then.
My suggestion would be to carefully measure voltages while the bed is running 100% at the Manta lugs, both at the bed power supply input to manta and bed output lugs.
to do what exacly? figure out where there is power loss?
Specs like this are usually meant as design parameters (don’t plan for supplying more current than X)
Yes, measure the resistance of bed as well (with power turned off). It will tell us 1. how much power it can draw at the voltage you are running it 2. how much power it is getting 3. if the manta board is leading to any losses
Yes, measure the resistance of bed as well
my bed resistance is 1.9Ω
that means that I = U/R = 24/1,9 = 12,63… A
And then you also have the motherboard and motors so my bed will probably consume about 12A when using this module, 25A is impossible then my PSU would blow up.
(pretty close to my guess in post #14)
checked the resistance of all my other wires and they are all 0.1Ω
so what do you guys think? should i swap back to using the MKS MOS25 or not?
Matna M8P using the bed heater connection (the large terminal block) should not have any troubles driving it.
Matna M8P using the bed heater connection (the large terminal block) should not have any troubles driving it.
okay, thank you.
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