Max hot end heater current

  • @T3P3Tony:

    I can confirm that the terminal blocks are rated to 10A. Make sure the wire you fit is also good for the current you are using and you have a good connection via a crimp ferrule in the terminal block.

    The traces are similar to the Heated bed in width and length, however they are not duplicated on both sides (due to space constraints) so 9A would be a good limit without further testing (18A for the heated bed, divided by 2).



    Thanks Tony - that's good info. It looks like with the 24v the current will be 3.33 Amps because the heater is 80W but with the 12v version the current will be 5 Amps because the heater is (only) 60W. A quick search shows that 12v 80W cartridges are available from China (so take that with a pinch of salt) but if someone does source and fit one they'll be drawing 6,67 Amps but that should still be safe.


  • @DjDemonD:

    Given Ian's testing with pushing three filaments simultaneously through the 3 colour diamond and being able to achieve way higher extrusion volume than volcano, an 80w heater might have its merits.

    Yeh. Now if I can print the in order of 150mm/sec with a single filament and 250mm/sec using 3filaments, it'll certainly be interesting to see what 5 will do 🙂

    I might yet start printing kitchen units and maybe a new bathroom suite….......

  • Just a hypothetical thought but I guess if one really wanted to push the limits, one could assign two heater channels to a hot end, then split the cartridge wire across two sets of terminals?

  • No, because there is no way of guaranteeing the current split.

  • administrators


    Just a hypothetical thought but I guess if one really wanted to push the limits, one could assign two heater channels to a hot end, then split the cartridge wire across two sets of terminals?

    Yeah at Tim says might not be even. If you needed to do that it would be better to have a hotend with two heater cartridge inputs and use two.

  • Ah OK. As I said, it was hypothetical - I think if I ever needed more than 216 Watts (9Amps at 24v) I'd use a blow torch in any case 🙂

  • By way of an update, I've now got the 5 colour diamond installed (but not loaded any filament yet). So I ran auto tune on this silly 80 Watt heater and got the message that the predicted temperature could reach 670 deg C. The result was gain 645.7, time constant 190.4 dead time 6.4. That's all with PWM set to 1.0. The high flow fan (20cfm) was running the whole time and blowing lots of air over the 5 heat sinks.

    This all strikes me as being far too excessive and I'm inclined to bung a standard 40Watt heater in (or run PWM at 0.5 but that seems pointless) despite what say. What do guys think?

    I'll email Peter Bogely and see if I can get a reason why he thinks the heater needs to be 80Watt.

  • Just another quick update on this. I never did get a reply from as to why they think an 80 Watt heater is necessary on the Diamond 5 colour. After I tuned the 80 Watt heater I found the temperature was overshooting quite a lot so I re-tuned it with a PWM of 0.6 which gave more sensible results and was more controllable. I've just changed the nozzle so while I had the hot end stripped down, I fitted a standard 40 Watt cartridge. I've just tuned it and can't see any substantial difference between the results I got with a 3 colour Diamond with 40 Watt heater and this 5 colour, also with a 40 Watt heater. So, I'm going to ignore's advice and run with this.

    One thing I do differently to the "official" assembly instructions is use PTFE tape on the heat sink threads. It's for sealing purposes but maybe it helps insulate the heat sinks from the brass nozzle so they don't conduct as much heat away? Dunno….

  • 80W is silly? I am testing custom 100W heaters with custom CNCed chrome plated elongated copper hotend. Hopefully board will do the job lol. Will report back if I fry it! lol

  • @Vlad:

    80W is silly? …................

    Yes! The Diamond hot end has 5 heat sinks all taking heat away but when I finally managed to tame the heat creep issues, I ended up with a huge 60mm, 30+ cfm fan blowing cool air over those 5 heat sinks and that was with a 40 Watt heater

    The diamond also has 5 melt chambers but a single 40 watt heater is more than capable of supplying enough heat to melt filament fast enough to be able to print at over 300mm/sec and

    I've read somewhere that the heat requirement to melt filament is in the region of single digit watts. The above tests would tend to back up that theory, so more watts won't help. (but larger or multiple melt zones will).

    As mentioned above, when the 80Watt heater was tuned, it showed a potential to reach 670 deg C - a 100 watt will be even worse so not only is it silly, but also a potential fire risk and downright dangerous IMO.

    In practice, trying to use the 80 Watt heater was very difficult due to overshoot issues. The PWM is trying to produce single digit watts from a heater that is about 10 times too powerful.

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