Faster Heat Up Times Larger Wire Size

Basic Information:

Printer Model: Ender 3 Pro
MCU / Printerboard: BTT SKR E3 V3

I have discovered that larger wire size significantly improves the heat up times for the hot end. As well, even though not changed, the bed heats faster.

This is a well tuned machine running Klipper , Mainsail.
I used 18 ga wire ( stranded ) and soldered the connections at the hot end, with heat shriink.
This worked on Micro Swiss and E3D hot ends.
Very stable temp levels during print.
Hope it helps someone along the way.

What was the size of the wire you were using previously?

18 gauge wire is a bit heavy for the hot end - I’d probably recommend 20 gauge as still being safe. I’m saying “a bit heavy” because wire gauges is a logarithmic scale so being able to go to the smallest diameter wire can have unexpected advantages in terms of weight and ease of bending (aka “flexure”) which are important in a 3D printer.

Here’s a good table for gauge/current carrying capability of different gauge wires including stranded:

No, you didn’t. The overall load for the heater might be 40W you might use 12V. 40W/12V = 3,3A.
R(heater) = 12V/3,3A = 3,6 Ohm. Cable should have 133 Ohm for 1000m (!) for AWG 24, so if you have 1m of cable (for both directions), if should be 0,133 Ohm in total. For a AWG18 it is 21 Ohm/1000m = 0,021 Ohm. Difference is 0,133-0,021 = 0,112 and this is 0,112/3,6 = 3%. This is not “significantly” in my eyes, even if I do not think, that the original one was a AWG24…(for AWG20->18 the value is 0,4%)

Other way around: If R(cable) would be 25% (=Significant") of R(heater), R(cable) would be 1,2 Ohm, power/heatloss in cable would be 1,2 Ohm*12V = 14,4W.
Means: if so, cables would melt, your plugs would melt, your printer would burn, smoke would fill the earth, birds would fall dead from sky, armageddon! There is no theory for this available for cables. Must be another reason, sorry. Maybe soldering or renewing the cables made this effect…

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