At the risk of incurring wrath from various quarters, I'm going to say a few words about single coil vs. dual coil as it relates to the vape and battery life, and variable voltage as well as it relates to the same.
This is a PM I just sent to someone asking about amp draw and how it is affected by using single or dual coils, and as I was typing it I was reminded of the importance of pointing out the advantages of variable voltage as it relates to the use of higher voltages as a means of extending battery life.
Here is my (abridged) PM:
XXXXX:
No problemo; let me dig up a couple of those posts, and I'll send you the links. And I really do appreciate the very, very friendly nature of your post; I really hope we can all get along in this war we're in against cigarettes, which kill 443,000 Americans every year.
Some of the conflicts on this site remind me of the rivalries between the different branches of the military in say, World War Two. The Marines might say to the Army "sure, we do the hard part - conduct an amphibious assault on a Pacific island and get our a$$es shot to hell, and then you guys go in a clean things up after we did the hard part". And the Army might say to the Navy "sure, you get to sleep in your nice, dry, cozy bunks and eat three nice hot meals a day while we sleep in foxholes, march through the mud, and get shelled and shot at 24/7". And on, and on .... Army, Navy, Air Force, Marines, Special Forces, Coast Guard ....... but I think the important point is that those branches of the military are
all on the same side, with the
same goal; in the case of World War Two, that goal was to defeat Germany and Japan. And as I said, our goal is to defeat cigarettes.
The reason I keep recommending variable voltage is that
it is a better weapon than fixed voltage. It just is. There is no question about that. This is not opinion. This transcends opinion, and resides squarely in the realm of the factual. Constant voltage is not better than variable voltage. A stove that has burners that can be set to just one temperature is not better than a stove that has adjustable-temperature burners. A toaster, iron, electric blanket, thermostat, lamp or any other device that has just one setting is not better than a similar device that can be set to different output evels. It just isn't.
Yes, there are some very cool, very fine constant voltage devices, than can be used an appreciated for what they are. I was just using my Joyetech 18650 mod yesterday for the hell of it, for a few toots. It's a cool device that is so big and fat and torpedo-like, with a really cool, clicky, rubbery switch that I just love it. And some people love the M1 Garand semi-automatic rifle that helped win World War 2. They buy them, maintain them, and shoot them so they can admire them for their coolness, their kick, and their awesomeness. But if those same people were about to go off to war, the would almost to a person want to use an AR15/M16 automatic if their lives depended on it.
The life of a newcomer depends on getting the best vape they can get. That is why I don't send them into battle with a constant voltage device. I send them into battle with the clearly superior weapon. I always will.
****
Short answer on amp draw:
As you know, volts x volts / resistance = watts.
The amp draw part is simple; it's just another part of Ohm's law that says that amps = watts divided by the amount of volts required to create them. (Amps = Watts/Volts)
So, with your 2ohm dual coil at say, 3.7 volts:
3.7 x 3.7 / 2 = 6.84 watts (and 3.42 watts
per coil)
6.84 watts / 3.7 volts = 1.85 amps to put 3.42 watts to each coil
To put 6.84 watts to each coil, it would take twice the watts, and therefore twice the amps, or 3.7 amps.
(My Smoktech VMax could do that, with its 5-amp limit, but the battery would run down twice as fast as it would if it was putting that 6.84 watt to just a single coil).
With a 2.0 ohm single coil:
3.7 x 3.7 / 2.0 = 6.84 watts on that single coil.
6.84 / 3.7 volts = 1.85 amps; again, half the amps for the same watts per coil vs. a dual coil.
And the higher the resistance of the coil, the lower the amp draw. This is counter-intuitive, but true.
If you use a 3 ohm single coil to arrive at the same wattage, you need more volts, but end up using fewer amps.
4.53 v x 4.53 v / 3 ohms = 6.84 watts.
6.84 watts / 4.53 volts = 1.51 amps. And since batteries are rated in milliamp hours - how many amps or fractions thereof can it put out for how long - you get better battery life with fewer amps. Using a higher resistance coil (assuming you can put out enough volts [
which a Twist can, and a kGo cannot]), or usng one coil instead of two [one coil does the job just fine IMO), will draw fewer amps and extendbattery life. Your weapon will need reloading less often, and you will have a better chance of defeating the enemy.
So to me, not only does variable voltage give you a better vape, it also can extend battery life. That is why I recommend it over fixed voltage.
Thanks again for the very friendly message, and please feel free to ask any questions you have. I don't know everything, that is for sure, but I do enjoy science, and I sure do enjoy vaping and getting people off of cigarettes.
Have a great day, and best wishes -
John D
*****
As always, peace out and vape on, all.
