VV/VW Theory

[hijack]

When you use an eGo that you get with a starter kit, the voltage is regulated (set) usually around 3.5-3.7 volts depending on the exact type you are using. When the battery drops below 3.2v, it says, ' I’m not going to fire anymore the voltage is to low '. You can usually tell the battery is almost dead by the way its vaping. That’s because the voltage changes little in that last bit down to the 3.2 volt cutoff.

VV/VW mods (variable voltage/variable wattage) have electronics in them which boost the voltage (V) of the battery. So, as the voltage in the battery drops, the voltage and power delivered to the coil remains constant to what you have set it at. This is why it is possible to set your mod to 6.0v when your battery is only 3.7v.(No need to try this, 6.0v will be way too high for a nice vape).

Being able to boost the power in this way will allow you to turn the vapor production up and down to suit your tastes.

VV stands for (variable volts). Volts (V) is the measurement of potential energy, and shows how much potential energy can be delivered to a point which in our case would be the coil in our atomizer. (It can be thought of as pressure) That pressure can be set at a specific value in volts (V) and will remain constant throughout the charge of the battery.

VW stands for (variable watts). Watts (P) is a measurement to show how much power is being delivered to a point. Again this will be our coil in the atomizer. (It can be thought of as a flow of water). This can also be set and will remain constant throughout the charge of the battery.

 It is this flow of power that determines how fast our coil heats up and how hot it gets.

 
                    You don't set both VV and then VW. It’s one or the other.

So why do they have both?

It’s because they each work in a different way to ultimately achieve the same result.

VV sets the voltage (V) (Pressure) available to the coil. The coil has Resistance(R) measured in Ohms and that resistance determines how many watts (P) (our flow of water) will flow through it. (Think of the coil as a straw). The thicker the straw, the less resistance, and more of our water (P) will flow through it.
If I were to change over to a different clearomizer (say I have one with a different flavor in it), and that clearomizer had a coil of a different resistance in it. Then the flow of power would change and my coil would behave very differently to the previous clearomizer I was using.
If the resistance changes and you are using VV, the voltage will remain constant to what you set it at. But when the resistance changes and the voltage remains constant, the result is a change in watts. This effects the speed the coil heats up and how hot it gets. So if you change atty and its resistance is different, your vaping experience will be different.

On the other hand if you are using VW and the resistance changes, the voltage will automatically adjust so that the same amount of watts (P) is given to the coil and the vape will be pretty much like it was before we change over to using a different resistance atty.

                                                 Here comes the maths.

Don’t run off, ill do all the working out I promise.

                                                          Ohms Law 

There is something called Ohms Law that we can use to see what happens in number terms.

                                  
The diagram above shows Ohms Law and all its possible variations and can be used to work out either: Volts(V), Watts(P),Resistance(R) or Amps(I)

Lets use our device and our atomizer as an example.

I set my device to 4.0 volts and I have a 2.0 Ohm attomiser. Using ohms law I can work out how many Watts will be traveling through the coil.

V²/R=P : 4.0x4.0/2.0=8 So set up like this, at 4 volts, I will be using 8 watts to heat my coil

Now ill change my clearomizer for one that has a 1.5 ohm atomizer in it.

V²/R=P : 4.0x4.0/1.5=10.67 So set up like this, at 4 volts, I will be using more than 10.6 watts to heat my coil. That may be why its started to taste a bit burnt. So I better turn it down a bit.

I can use that chart to tell me what volts I need to use to achieve 8 watts.

?(PxR)=V : ?(8x1.5)=?12 Time to get the calculator out…….Its 3.46 so I need to set my voltage at 3.4-3.5 to get close to the 8 watts I like to vape at.

                                  That's the maths over with

What I could have done was just set my device to VW and set it to 8 watts when I’m using it. Then changing the atty over from a 2.0 to a 1.5 wouldn’t have caused a problem as it would still be giving 8 watts to the coil.

Here is a handy Ohms law calculator where you just need to supply 2 values, and it will work out the rest. Steam Engine

 
I hope all this helps to understand how a VV/VW device works.

Read through it again if it doesn’t make sense. I know I had to when first trying to get to grips with it.

[sleedale]

It does make sense, I'd have to read it carefully with a calculator to properly get to grips with it.

But what I do know for sure..........should've bought a VV/VW not a VV icon_shoppingm

Very helpful for a newb, thank you

[hijack]

You haven't wasted your money sleedale if your talking about a spinner or similar then they do the job of letting you vape at higher or lower voltage.

To quote from my guide. ''they each work in a different way to ultimately achieve the same result.''

[alansi]

Jun 7, 2014 20:30:58 GMT sleedale said:

It does make sense, I'd have to read it carefully with a calculator to properly get to grips with it.

But what I do know for sure..........should've bought a VV/VW not a VV icon_shoppingm

Very helpful for a newb, thank you

Very simple rule: If you normally use atomizers with the same resistance, the VV version will suits you, in case of varios resistance VW is better solution.

[buggritt]

Not strictly true for me. I've said this before, but I change the watts I vape at quite often. Cooler in the morning, then hotter later. Also I vape citrus at a lower wattage. And, of course, changing the wattage is the same as changing the voltage.
Though I rarely use one now, a bottom coil clearo needs more power for me to be a good vape.

[hijack]

I wasn't try to suggest that everyone should set their device to 8 watts and leave it there. They are examples, to show the relationship between volts, resistance, and watts and how the two modes work in a different way ''to ultimately achieve the same result.''

For a beginner who doesn't know the difference between vv and vw it is meant to explain a few basic principles, and clear up a recurring misconception about setting volts and then watts.

[Yasumi]

Pressure, flow of water and a straw. Why, oh why didn't anybody explain it to me this way before? At last I've got a basic understanding of what I'm doing! (Maths, well, not so much, I'll come back to it when my mod hits the mailbox.) hijack, so many thanks.

[hijack]

Yasumi I glad it has helped you. I don't do the maths side when making a coil ect, I cheat and use ohmslawcalculator. But I felt that my guide needed it explained in numbers as well to prove the theory.

[Yasumi]

hijack Of course, the maths section will help a lot of people who are not mathematically impaired as I am... Thanks for the link! There is also this fantastic page, a microcoil calculator. link Granted, it's in French, but tech words are so similar it shouldn't be a problem. ("Largeur" is "width" or "gauge", that's the only difficulty I can see.) Enjoy!

[hijack]

Yasumi you may prefer this one as you can change it to English and its a stand alone software app link

software by by Luc BigJohn,

[Super-Shiny]

hijack i tend to find this one more better, plus you can click anywhere on the info for even more info: coiltoy.ermeso.com/

I do prefer to use custom AWG on the drop down though.

[hijack]

Super-Shiny thanks I like the fact it works out duel coils ive bookmarked it.

[buggritt]

Jun 8, 2014 9:04:18 GMT hijack said:

I wasn't try to suggest that everyone should set their device to 8 watts and leave it there. They are examples, to show the relationship between volts, resistance, and watts and how the two modes work in a different way ''to ultimately achieve the same result.''

For a beginner who doesn't know the difference between vv and vw it is meant to explain a few basic principles, and clear up a recurring misconception about setting volts and then watts.

I think you've taken my post as e reply to yours. It's not. I'm pointing out that vw is not a one shot setting. I'm frequently upping and downing, even with the same atty and juice, depending on how I want the vape.
vv is fine - coupled with ohms checking ability to make it easier. It was more in response to the poster who wishes he had vw. Provari users get on fine without
Your explanation is spot on.

[hijack]

Yes when I read, I thought you had seen my examples and thought I was suggesting to set in watts and leave it there. buggritt  I misunderstood you.

I too use varying amounts of power depending on what im using. I vape my kayfun much higher than I would my clearomizers.

[robby]

Great post, the water analogy works well