Quesion about building RBA coils.

[mantiz]

I looked around the forum and couldn't find an answer to my question so I hope someone can make sense of the confusion for me.
I built a beautiful 28 gauge chimney coil with cotton wick on a kayfun clone that reads as 1.8ohm. (great vapour and flavor BTW).
When researching volts/watts and ohms I came across the vaping ohm's chart.
I am running my coil at 13 watts and I find that's my sweet spot but according to the chart, I should be burning the crap out of the juice. Can anyone see why I am confused?

 

[Izan]

Consider the chart as an ohms law cheat sheet. It is NOT gospel. It just saves me doing the math in my head.

Cheers
I

 

[mantiz]

Thanks Izan,
I had the feeling that was the issue. I just didn't think the chart could be that inaccurate with hand made coils on an RBA. It does apply to my protanks built with 32 gauge. Maybe it has something to do with microcoils and thicker wire? hmmm...

 

[Nat79]

I think (IMO) the wattage cheat sheets help where their is rubber or filler surrounding the coil. A RBA/RTA usually keep anything that would funk the taste a little further from the coil.

 

[Thunderball]

I have never found those charts to be accurate for any way I vape.

 

[mantiz]

I have been thinking about this issue... We know that as the resistance of the wire decreases, wire thickness increases. This is why we sometimes like to use less resistance. A longer wire and greater surface area can provide more vapor theoretically. But as thickness and length of wire increases the more wattage / voltage is needed to get the wire temperature required to vaporize the liquid.
I think that is why the chart doesn't always apply. It's written for a single gauge of wire. Maybe 32.
I'm not an electronics expert so I could be completely wrong. Anyone else want to chime in?

 

[supertrunker]

You also have to remember that there is a mass associated with that wire, and so thicker (lower R) wire will take a long time to heat up and cool down again. It's a lot more metal to heat.

In practical terms it means i can achieve the same results using 26g single coils, 30g single coils with more wraps, or 32g duals. Which you prefer really depends on what wicks you are using as well as your batteries and vaping preferences. I never found those charts to be that accurate or applicable to what i do. I just make sure i test anything i have built before i fire it up to try to avoid any nasty surprises.

T

 

[Nomoreash]

Forget charts, if it's working for you that's all that matters. Charts don't account for the wick, coil, how much juice it's feeding etc etc. Most people find their sweet spot higher with RBA builds over mass produced attys because they use bigger coils, wicks and have better airflow among other things.

 

[Thrasher]

most of the wattage charts are mainly for cartos and clearos.

 

[piggy]

I'm thinking it's the amount of wick and juice available for the coil. The micro dragon coils that uses a lot of wick and juice works best at 12+ watts, while the standard wick through the coil works best at 8.5 watts for me.

 

[beckdg]

most of the wattage charts are mainly for cartos and clearos.

this is what i gather with the addition that it's likely with high gauge wire and/or stock coils and heads.