CoilCalc Spreadsheet

[DejayRezme]

This is strange, don't know where the "30ga A1 is 8.36 Ω" comes from. But apparently there is also a difference due to the imperial unit system still used in the US and the metric system used worldwide. Apparently manufacturers create different wires for those two markets. Not sure about this, but this is what I've seen on a European website vs the "precise AWG to mm" formula:

Metric (based on 0.2500mm)
Kanthal A-1 - 30 AWG - 0,00984 inch - 0.25 mm - 29,5 Ohm/m - 9,004 Ohm / Ft

American (based on 30 AWG)
Kanthal A-1 - 30 AWG - 0,01003 inch - 0.2546 mm - 28,473 Ohm/m - 8,678 Ohm / Ft

PS: The vape Knowledge page probably lists Kanthal D or A not Kanthal A1

 

[svg1234]

So Dejay, in reality we don't even know what we really have? lol. There's also the issue that even if we have the exact specs, we really don't know if the wire itself was manufactured precisely to those specs. Probably not.

On top of the uncertainty of the wire's resistance, there is also an inconsistency in the mandrels. Compare a bunch of 5/64" drill bits or whatever and you will see that they are not equal. So we think we're using 5/64" or 1/16" but that may not be the case.

Then we also have the reality that the battery ohm meters are not exactly accurate either. Same coil, a few vapes apart, and the meter can change as much as a few points. The contact of the coil comes into play too. A little tighter or looser makes a difference.

You can use the "legs" table as an overall adjustment factor to account for the difference between what the sheet projects vs. the actual figure.

The formula in the sheet is definitely correct and will give 100% accurate results given accurate data...but if we feed it data that isn't precise, obviously the results will not be 100% accurate.

Although the sheet may not be perfectly accurate due to all these issues, it's still close enough to let you know the range of possibilities for a given setup.

 

[DejayRezme]

Well I think you just need to be weary if you buy from US or european / worldwide vendor. I really don't think a tiny difference is important, I only posted this to maybe clear up some confusion. Ultimately you're more precise with the diameter in mm (0.254 or 0.250 for 30ga) and the ohm number given for a wire is likely precise also.