Newbie: Why don't we only talk about power (watts)?

[Gummy Bear]

Yes, look at an analog for a bit, most all of them have the exact same few things in common, Paper thickness, tobacco, filter, diameter, length, and of course the fire. the heat from the fire can all be calculated to a given BTU that should result is the same temp of the smoke (as long as all things are equal). Yet because all analogs (for the most part) will also have about the same particle size, they almost all give off the same amount of smoke per second of draw time. All of the things mentioned above can be used to calculate a given amount of smoke, but no two brands taste the same. Yes I know it's because of the additives. but in a way the same is true with our PVs. We can regulate a few common things (Watt's/oHm's law) and get the end result that's close, such as the same temp of the vapor but in our case something as simple as how fast it gets to that temp has an effect on the vape's taste. Having said all that think about how many years and how many dollars of research money that big tobacco has put into their products. E-cigs have only been around for a very short while. given time we will make leaps and bounds. Another thing to think about is how even with the same tobacco, the same fire, the same smoker's puffing style,,, no two tobacco pipes taste the same either.

 

[N2rock]

Very well put Gummy.

And there is also inconsistency with the atty's/cartos. I have a box carto's- Thanks to my Darwin I can see the actual ohms of each one. The last 3- one was 2.9, one was 3.0, and the one I'm using now is 3.1. So obviously there are variations within. The good thing about the Darwin is since it bases its power output on the watts, it automatically adjust itself to my preferred vape regardless of the differences in the resistance of the carto.

 

[Gummy Bear]

Thanks Rock, A Darwen, You would be the perfect one to ask then. If you set it to lets say 7 watts and screw a 2.5 oHm atty on it and vape it for a while, then change it for the same brand atty, same brand juice only now it's a 3.5 oHm atty,,, can you taste a small difference?

 

[N2rock]

You should not taste any difference, since it would be the same output. I primarily use standard res cartos with it. But I ran out (I have some on order) and had some un-used LR cartos (I used to use LR only on my eGo). Put the LR on the Darwin, and no difference in taste or vape as it automatically adjusted to where it was putting out 7w.

 

[schaedj]

The "taste" on my Darwin tends to vary more with atty type than any other factor. I've gained a whole new appreciation for the 901 form factor atty / cart, as it seems to me to really hold flavor and generate warm vapor at higher wattages than the 510. The 510 cranks vapor but loses taste rapidly (burnt / hot taste) as you move up. The only downside to the Darwin from a Variable perspective is that you can't set a max voltage, so it will pop an atty fast if you accidentally slide the watt wheel up too high.
To the OP's post, I think the primary reason discussion hangs around Volts rather than Watts is that we are severely restricted (without custom electronics) as to our control of wattage. Since you can buy batteries in 3.0, 3.7 (standard types) and atties in specific resistances (basically Low, Medium and High), those are the variables we play with to find our sweet spot. In the back of our mind, we know that wattage is the true measure of heat output, most people moving (gently) into the mod world have limited choices (3.0,3.7,5V reg, 6.0) on voltage, so the question is: how do I get the vape I want with the simplest variables I can control. I jumped on the Darwin because it's an early device that shoots for the real target. Now I can grab any of the dozens of atomizers I have piled up in the drawer (with the right adapter), and get right to the vape I want without worrying about battery combinations / etc.

 

[Gummy Bear]

Well cool,,, Every time I try to test out the different atties I seem to pick a change in taste but, I don't have a Darwin either. (and at their price, I may never get one).

 

[AriM]

IMO the main reason we talk in volts, is because most e-cig designs start with a specific battery voltage. Or should I say a voltage range. Watts really is the most appropriate term if your design options are unlimited. Just keep in mind that w/o some kind of voltage regulation, and a clear indication of amp draw (and whether that draw is even possible from your electronics) most folks options are based on the fixed voltage range of their power source. That is my opinion on the matter. So volts has become the reference, even though it is somewhat inaccurate. I have done extensive research on this (even started a thread a while back).

After testing dozens of attys (of various impedance's, using a highly regulated and accurate lab grade power supply)....I came to the conclusion, that the ideal wattage range is 8-10 watts, depending on juice. Also it is crucial that your circuit and power source will allow for at least 2 amps draw. I compiled a list of all of these variables (amp draw vs different loads and batteries, and ideal mean voltages for flat discharge pulses) and generated a loose average, to arrive at those figures.

The ideal power source and atty combo, turned out to be a hi-discharge (11.1, 25c) Li-Poly. Followed by a high quality DC-DC switching regulator(running between 4.1 and 5.2 volts) and a home-made coil with a resistance of 2.36 ohm. At least that gave me the most satisfying vape for my tastes, with a large variety of juice formulations.

The reason for me using the 11.1 source was that it provided the flattest discharge curve through the regulator. So the vape was consistent from the first hit, down to the safety limit of the pack. The regulator didn't fluctuate at all with that source.

I tried a similar setup with a 7.4 volt pack, and the discharge curve was not flat at all, and lead to an inconsistent vape. This is, of course, dependent on the regulator you use and the ranges it likes to live in. There is no simple formula for this, as the variety in power sources and regulators is MASSIVE.

So in that case, volts is a very appropriate descriptor. My wattage stayed the same at the atty. A higher voltage pack was necessary to keep a flatter discharge curve. So I guess it is all really relevant. Also it's so specific to the situation.

Just my 2 cents...