Can’t Pass 250°
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@fcwilt I have a 12V system. The side of the PSU says its rated up to 360 Watts.
As for the the heater cartridge, its the stock one that came with this Cr-10 Mini that I’ve been modifying. I’ll take it apart here in a bit and hopefully the wattage is listed on it somewhere.
Any recommendations on a better PSU and heater cartridge?
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Have you changed the thermistor that you are using? A standard thermistor poops out at around 300C and even if everything is ok, you will never reach 350C.
Maybe the current thermistor is marginal and only allows 250C?
Don't know but worth looking into.
As for heater wattage, P=V**2/R, V=12V so all you need to do is measure R to calculate wattage. Note that R increases a bit with temperature so this will only give you a rough idea. -
@tmeryhew said in Can’t Pass 250°:
@fcwilt I have a 12V system. The side of the PSU says its rated up to 360 Watts.
As for the the heater cartridge, its the stock one that came with this Cr-10 Mini that I’ve been modifying. I’ll take it apart here in a bit and hopefully the wattage is listed on it somewhere.
Any recommendations on a better PSU and heater cartridge?
Amazon has this which should be suitable: MEAN WELL LRS-350-24 350.4W 24V 14.6 Amp
Amazon also has 24v heater cartridges. A quick check showed several ranging from 40 to 65 watt. There is probably some way to determine the ideal wattage rating but I don't know what it is. You can control how much power is feed to the heater so if the ideal value was, say, 50 and you got a 65 you could just reduce power to obtain a good result.
As to fans it is usually easy to find a fan that matches what you have but in a 24v version. There has only been one time in my experience that I could not find a matching 24v fan.
If you happen to have a setup with uses a pair of matching 12v fans you can wire them in series and run them off 24v.
Frederick
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I just pulled out the heater and checked. It’s a 12V 40W heater cartridge.
I would think this should heat up past 250°.
Also, I put a PT1000 sensor in.
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@tmeryhew said in Can’t Pass 250°:
I just pulled out the heater and checked. It’s a 12V 40W heater cartridge.
Good to know.
I would think this should heat up past 250°
There are several factors that come into play which might make the 40w too small.
For $8-$9 you can get a 12v 60w on Amazon. Get one of those and get it a try.
Also, I put a PT1000 sensor in.
That's good but it won't solve the problem of an underpowered heater.
Frederick
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A 40W heater should get you to at least 300 degrees with everything else working properly.
An interesting thing to think about with a 12V heater .... there is considerable current flowing (3.35A) which might not sound like much but if your wiring is too thin, if you have connectors in the heater line or if your heater wires are excessively long then you might get too much of a voltage drop which could really screw with your power output.
The reason I know this - I had a connector in my heater line in order to replace the heater when needed. That connector heated up excessively, melted the plastic housing and eventually failed. This is the point where I switched to a 24V setup. Double the voltage, half the current .... happy connector, happy operator
Might not apply to you but thought I would mention it anyway.
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@tmeryhew said in Can’t Pass 250°:
I just pulled out the heater and checked. It’s a 12V 40W heater cartridge.
I would think this should heat up past 250°.
Also, I put a PT1000 sensor in.
If you have access to a multimeter, it might be worth checking the cartridge resistance to ensure that it is what it says it is. Ohm's law gives us R=V/I = 12/3.35 = approx 3.5 Ohm's for a 40Watt heater at 12V. If the resistance is significantly higher, then the wattage will be correspondingly lower.
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I just checked. I’m getting 4.4 ohms across the heater cartridge leads.
So my calculation is 32W at the cartridge.
Also, I rewired it directly to the board, same 250° top end limitation.
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@tmeryhew said in Can’t Pass 250°:
I just checked. I’m getting 4.4 ohms across the heater cartridge leads.
So my calculation is 32W at the cartridge.
Also, I rewired it directly to the board, same 250° top end limitation.
That measurement is usually good enough to get an idea of what the rating is.
But the resistance can drop as the cartridge heats yielding a higher wattage output.
Frederick
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@tmeryhew said in Can’t Pass 250°:
M501 ; load saved parameters from non-volatile memory
Have you also checked your config-override,.g ?
