I have a X1 Carbon plus AMS being delivered tomorrow. I understand the heat bed is powered using mains voltage and the printer has automatic mains voltage selection. I( also saw that power draw and maximum heat bed temperature are vastly different when run on 120V as versus 240V. I am assuming the X1 Carbon ships with a standard 120V US power cord: 5-15P plug to IEC 60320 socket.
I am in the US and have 120V and 240V 60Hz mains power available. Is there any advantage to swapping the power cord and running the X1C from 240V mains voltage? Or does that involve changing the bed heating element?
There is no change needed other than the cord. If you have 240V power available, you can use it. The maximum bed temp is actually 10C lower on 240V than 120V, but it heats up much faster.
The only advantage to switching to 240v from your standard 120v, is load balancing of your main panel phases and apparent power demands at the utilities providing you energy.
So unless you know your panel is not load balanced properly I would not worry a second on this matter.
In modern switching power supplies, the only slight advantage to using 220/240 watts is that the energy conversion is more efficient at 220/240VAC. However, that means absolutely zero to you or anyone else who isn’t running a data center or crypto mining operation. After the power conversion is done, the 24vdc output of the supply looks no different to the motherboard or print head whether you plug it into a 120VAC or 220VAC outlet. You might enjoy the need for slightly less air conditioning if you have let’s say a small room with 20 or more of these running.
This is a question that truly only has relevance in data centers and crypto mining where energy efficiency matters. I had researched this back in my crypto mining days when hashrate/watt was key to profitability. I had a watt meter on all my mining rigs and the best I saw was maybe a 3% reduction in power draw. I wasn’t running enough rigs to make it worth it and once I realized it would never be profitable at most residential utility rates, I bailed on the effort.
My advice? Don’t over-think this. Stick with 120VAC. Not only is it safer for the average consumer but it’s a waste of wiring to use 220/240VAC on such a low power-draw device. The most I was ever able to measure on my P1P during simultaneous warmup of the bed and nozzle was 265W. To put that in perspective, my 10th generation I7 with an NVidia 3080 TI card at full overclock, at best can get up to 550W power draw and that is only when I’m doing benchmarking.
I have an Electrical Engineering background and so my question is relevant – it’s a reasonable question and I don’t see it as “over-thinking”, but I could be wrong.
The question is not “220/240 watts” as you state, but the difference in bed heating on 120VAC vs. 240VAC. I’m totally unconcerned with the MeanWell or equivalent 100-Watt PSU which powers the electronics, stepper motors, fans and hot end. I AM interested in why there are different maximum temps for the heated bed depending upon the mains voltage, as well as potential differences in the warm-up time for that heated bed.
The specifications page does not include enough information for me to understand why 120VAC and 240VAC mains results in different performance specs. Thus the question: is it better to use 120V or 240V to power this printer? To simplify/clarify that question, does the heated bed – running off of mains voltage – perform better on 120VAC or 240VAC? An additional question would be: are there different bed heaters for 120VAC regions than 240VAC regions? Or are they the same heater?
These are reasonable questions for an anal-retentive, technically-obsessed, OCD engineer like myself.
Thanks for your reply, but I think you’ve misunderstood my question. That’s probably my fault for not being more clear.
I already expect the X1C to be delivered with a 120V power cord for delivery in the US. It is common for manufacturers to include a power cords for the country the product is delivered and intended to be used in. I already understand the printer is usable on 120VAC/240VAC 50/60Hz mains and that a power cord change accommodates all options.
My clarified question is: Why does the heated bed perform differently when the printer is supplied by 120VAC than when it is supplied by 240VAC? Is it the same bed heater for both markets and therefore it has a different temperature coefficient when operated from different voltages?
I;m asking for someone knowledgeable to fill me in on the difference and - from there - I can decide whether there is an advantage to operating the printer from 240VAC instead of the 120VAC that is probably intended for printers shipped to the US market.
The reason the heated bed performs differently under 240V is that it is driven directly by the mains voltage, unlike the rest of the printer which runs from the regulated 24V supply. Given that the bed has a fixed resistance (when cold), doubling the voltage doubles the current and quadruples the power. The heater is a “PTC” device and its resistance goes up as it heats. The printer monitors the temperature and turns power to the bed on and off as needed.
That’s the detail I needed - thank you very much! To restate for the benefit of others who might have the same question:
The heat bed element is operated directly off the mains, regardless of supply voltage. It is a positive temperature coefficient (PTC) design, where resistance increases as the element warms.
With a power cord appropriate for the locale, the printer can be operated from any combination of 120/240VAC and 50/60Hz mains. For those with the option of using either 120V or 240V, the choice involves two trade-offs: For 120V operation, the heat bed PTC element will draw around ~350W when cold and will take longer to come up to temperature. With 240V operation, the heat bed PTC element will draw around 1000W when cold and will heat up very quickly. However, the heat bed maximum temperature will be 10C less when using 240V.
In each case, the wattages given above are maximums when the bed is cold. Due to the PTC heating element, these wattages will decrease as the bed warms and the PTC element resistance increases.
If you are just getting the 110v power wire, can you run the 240v from the box into a standard outlet or do you have to convert the power wire off the XC1?
The bed itself is grounded. The heating element is electrically insulated from the bed, but no insulators are perfect and so there is some leakage. In the US, maximum acceptable leakage is 5ma.
As the bed gets hot, the electrical insulators become “less perfect” and the resistance decreases. At any given resistance value, twice as much current will flow at 240V than at 120V.
I think Bambu found that variances in heating element production resulted in some beds at 110C and 240V were leaking too much current. As a workaround, I think Bambu limited the bed temp on 240V applications to keep the leakage to under 5ma.
Bambu could probably have changed heating elements to a type with better electrical insulation, but that might have been too expensive of a change.
If the circuit supplying the outlet also supports other outlets, lights or switches, then there’s nothing you can do.
If the circuit supplying the outlet is dedicated and doesn’t support any other outlets, lights or switches, you could change the breaker and the receptacle and use the same wire in between. You would need to “change the color” of the white neutral conductor at both ends to signify that it is being used as a line (hot) conductor.
If you go this route, you should probably involve an electrician.
