Hi guys,
I apologize throwing a cold shower on this enthusiast community, but there's something I believe should be known. Sorry Imeo, but I'm sure you'll agree that it's better to be safe than sorry.
I'm punching myself on the head for not having thought of this earlier, but so it happened. What awoke me was Tim's video, it made me smile because he makes a wishful guess that the autonomy of the GG would be big. This started a chain of thoughts that led me to notice some worrying facts. Let me share it:
The GG should run at least twice as long since it uses not one but two batteries, right? Wrong!!! Since it uses two batteries it will last only half of the time.
What? Is Tico crazy? LOL, no I'm not. I have been doing electronics as a hobby for some decades. Ask anyone who knows just the basics of electronics (Ohm's Law and what Watts are) and he/she will confirm that all what follows is right.
There are two ways of joining two batteries: in parallel or in series.
If you put them in parallel the voltage will remain the same. (What is voltage? It's a bit like the equivalent of what pressure is in hydraulics. Just for the sake of understanding, it's like the strength with which the electricity inside the battery is pushing.) At the same time the ability to produce current doubles. You can have twice the current for the same time or the same current for twice the time (What is current? It's a measure of how much electricity flows from the positive pole to the negative. The equivalent in hydraulics could be how many gallons per minute flow inside a pipe.)
If instead you connect the two batteries in series (as they are inside the GG) the voltage doubles and the capacity to produce current remains the same.
But if you double the voltage that you apply to the atomizer, also the current that flows through it will double. This is what Ohm's law says: I = V/R or, in plain English: the current that flows is equal to the voltage applied divided by the resistance. (What is resistance? The word itself says is: it's the resistance that any object opposes to an electrical current trying to flow through it). The resistance of the atomizer has not changed, it's the very same atomizer, but with two batteries in series the voltage is doubled and as a consequence also the current that flows through the atomizer doubles.
As we saw earlier, the capacity to sustain an electrical current of two batteries in series is the same as that of a single battery. So, since the current has doubled and the capacity is still the same the batteries will last only half of the time.
Quite unexpected, isn't it? I guess that most or maybe everyone, just as Tim, would have thought: With two batteries it will last twice longer. The surprise is that it will only last half the time instead.
And now the real trouble starts.....
Let's talk about power. What is power? In physics it's the capacity to produce work. And in electricity power is measured in Watts. Everyone met them, but what are they exactly? Power, in Watts, is the product of the voltage by the current. But if the voltage has doubled, and also the current has doubled the power, the Watts we are feeding into the atomizer, has quadrupled! Yes, 2 times the voltage by 2 times the current makes 4 times the power (the Watts).
Once again quite unexpected, isn't it? I believe that Imeo, and many with him, believed the GG was running at twice the normal rate. Two batteries = twice the power, simple isn't it? No, it's wrong, the GG with 2 batteries runs at 4 times the power!!! Where does that power go? That power goes inside the atomizer where it is converted into heat. 4 times furiously more heat! Scary!
You look at it this way: We doubled the batteries but they last only half, it means we are using the electricity four times faster.
Allow me to add another physics phenomenon that is useful. No worry, it's very simple: what happens when we put a pan of water on the fire? The fire heats the water up to 100 degrees celsius (You imperial people know for sure how much that is in fahrenheit. Forgive me, I don't) then the water starts to boil and more and more water turn into steam (water vapor if you prefer the term). And what about the temperature? While there's still water the temperature remains at a 100 degrees and does not rise above that. Why not? Because at standard pressure water cannot exist in liquid form at temperatures above 100. And all of the heat that we supply does not raise the temperature but instead causes more water to evaporate. Only when there is no more water left the heat can make the temperature raise above 100.
Back to our atomizer: inside it too there is some liquid that is heated and turns into vapor. But there's a big difference: in the pan the water is all there from the start. In the atomizer, the liquid is fed by some very porous material that uses capillarity to move it. What is capillarity? When a liquid encounters a small passage, there's a force that develops and tends to attract the water to fill the passage. That effect is called capillarity, and the tinier the passage, the stronger the force pushing the liquid through it. An example: hold some piece of fabric above a container full of water and lower it to touch the water. Water will soak the fabric and move upwards, even if that movement is against the force of gravity. How does that happen? It's the capillary force that develops in the tiny spaces between the very fibers of the fabric itself that pulls the water up.
Inside the atomizer there are pieces of sintered metal and fiberglass fibers that do the same, and through capillarity feed the juice from the cartridge to the heating coil. What is sintered metal? Get some metal in small particles, can be anything from small spheres down to fine powder. Heat it close to (but still below) its melting point and press it hard together. The skin of the particles will fuse together, but only the skin. All the spaces between the particles will remain and form a web of tiny passages, like an ultra-fine metal sponge. Those passages will have a very strong capillary effect and will drain and move liquids, exactly like the fabric dipped in water does.
That is what the arc shaped piece you can see inside the atomizers does. The surface looks quite grainy, doesn't it? That's because it's sintered metal, small metal grains pressed together into a metal sponge.
--- Let's make a pause here: all what I described up to here is sure, 100% physics, 100% facts. What follows is only possibility, some of it might happen, or maybe it doesn't, I don't know for sure. I know some electronics but too little chemistry. Maybe some other member knows and can tell us more about it (please).
What happens when we supply 4 times more power to our atomizer? More liquid will vaporize, that's the desired effect, and is everyone's experience with the GG. But can the device supply liquid to the heating coil 4 times faster? I don't know for sure but would bet it can't. Systems usually are built with some margin, but I don't think that margin here could be "4 times higher than the expected". It would be anti-economical, bigger i.e. no longer "cigarette-size", and there would be no reason to overdo it that much.
So what happens if the heat generated is more than what's needed to vaporize the highest flow the feeding system can deliver? In other words: what if, after vaping all of the liquid that is reaching the heater at the max possible flow, there's still some extra heat left? Please remember that the passages the liquid moves through are very small: while that grants a strong capillarity, it also impedes great speeds and big flows. As we saw earlier with the pan once all the water is gone, that extra heat would raise the temperature beyond boiling point. Does it happen in the atomizer too? I don't know for sure but my strong opinion is that it does. And if that actually happens, what are the effects, what are the consequences? Again I don't know for sure, maybe someone more expert in chemistry does know and can tell us. But what I fear might happen is that once they are subject to temperatures higher than the expected one, some materials like plastic or wires insulations might start releasing some undesired and easily unhealthy fumes. And is it possible that some of the components of the juice when subjected to higher temperatures could react together or break down, producing some other unexpected compound? Could some of these be dangerous? I don't know, anyone here does?
But it scares me a bit... One of the prides of e-cigs over analogs is that by not burning, not using a flame, they do not produce any additional unhealthy compound. Are we sure we're not raising the temperature high enough to start doing some of that in e-gigs too? I don't know, but it would really be a sad step-back if we did.
One thing I know: I quickly get rather hot vapors that also burn my throat. Not the kick we expect and love, rather an acid etching unpleasant sensation. Sorry guys, but that is my experience and I don't like it. I don't like it because it doesn't feel pleasant and it doesn't feel healthy.
One final due note: because the double batteries that are used have a voltage that is a bit lower than than the standard single one, the actual power increase is not exactly 4 times, but rather around 3 times. Still looks too much and a bit scary to me. I believe that some sure validation would still be wise, before accepting that as OK and safe.
Rather, to have it run at just twice the power, total voltage should be raised from 3.6 only to 5.1 volts. Two 2.5 volts batteries would do that, if they can be found.
So help and info from a chemist is much needed here to have some final answers and hopefully some reassurance. Thanks.
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I'm not mother-language and I don't have a degree in science: there might be mistakes in the text above. If there's any, I apologize. Just point them out, please, and I'll correct them. Thank you.
