# Vw Explained As I Understand It



## Hein510 (4/3/14)

I've been watching a lot of Youtube vids of guys testing vape equipment running at 20 plus watts!

Now back then (last week) I still had a VV battery that could go up to 4.8 volts and running that with my 2.2 Ohms coil only gave me round 10 watts

Now vaping at 10 watts was not very nice as it almost gave me an instant throat burn inhaling wat felt like breathing in the middle of a bush fire!

So I backed the volts down to 4 volts and could vape there for short periods of time without a burn taste, chain vaping will bring the volts back down again to 3.7 volts.

Now with the SVD I was a little sceptic about the variable watts function but instantly fell in love with it!

So I'm vaping at 12 watts at the moment working up to 15! Why is there no burn? I'm vaping way higher than I did last week!

Ok so the way I worked it out is the unit tunes the volts to keep the watts constant, starting up will maybe send out 5 volts to get it hot and up to 12 watts and then the Ohms of the coil also starts to change, I think the Ohms drops a little (drops from 2.2 ohms to maybe 1.8 ohms, so lower Ohms means less volts, so the unit automaticly brings the volts down to maybe let's say 4 volts to still keep that 12 watts going.

who knows how VW works? Why don't VW give me burn taste at high watts? Am I thinking this all out right or have I got it way wrong?

Sent from my BlackBerry 9800 using Tapatalk


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## Gazzacpt (4/3/14)

Hein510 said:


> I've been watching a lot of Youtube vids of guys testing vape equipment running at 20 plus watts!
> 
> Now back then (last week) I still had a VV battery that could go up to 4.8 volts and running that with my 2.2 Ohms coil only gave me round 10 watts
> 
> ...



Morning @Hein510

Read this thread most of you questions are answered there.


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## BhavZ (4/3/14)

Gazzacpt said:


> Morning @Hein510
> 
> Read this thread most of you questions are answered there.



A bit off topic, but how did you assign an alias to your hyperlink?


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## Derick (4/3/14)

BhavZ said:


> A bit off topic, but how did you assign an alias to your hyperlink?


Highlight the word/sentence you want to make a hyperlink and hit the hyperlink button - then enter your url

Reactions: Informative 1


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## BhavZ (4/3/14)

Derick said:


> Highlight the word/sentence you want to make a hyperlink and hit the hyperlink button - then enter your url


Thanks!


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## Andre (4/3/14)

Derick said:


> Highlight the word/sentence you want to make a hyperlink and hit the hyperlink button - then enter your url


Ah, thanks @Derick, now I can make my sentences much shorter!


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## Silver (4/3/14)

Thanks @Derick!


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## Silver (4/3/14)

Hi @Hein510 , that is a good question. 

I checked the link that Gazza provided, but dont think that thread dealt with your question directly. 

To me, Watts is Watts. So at the same wattage for the same resitance, the vape should be identical. 

I dont know why you are experiencing a difference but my only suspicion is that the circuitry works differently on the two devices. I havent witnessed that myself. I need to go test it. 

@johanct , what do you make of this?


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## Andre (4/3/14)

Your are quite correct @Hein510, VW automatically adjust for resistance, which VV cannot do. Have been wondering about your question as well for some time and your theory sounds very plausible to me. Would love to hear @johanct explaining this to us in layman's terms.


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## johan (4/3/14)

P = V x I, where P = power // Watts, V = volts, and I = current // Amps (V = P /I and I = P/V)
V = I x R, where R = resistance // Ohms (I = V / R and R = V / I)
- on another thread I mentioned that you have to see Ohms law in 3-dimensions to fully comprehend what happens when you change 1 or more parameters. I suggest you make simple spread sheet and put aforementioned equation - then change the Voltage if you vary the voltage or Wattage if you change same. There is also plenty online calculators you can play with on the web. Your coil resistance is fixed and does not change, irrespective of change in voltage in the case of a VV mod, the only thing that changes in this setup is the current. When you change the Wattage with a VW mod, you have to use both aforementioned equations to see the picture. Hope this help you.


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## Andre (4/3/14)

johanct said:


> P = V x I, where P = power // Watts, V = volts, and I = current // Amps (V = P /I and I = P/V)
> V = I x R, where R = resistance // Ohms (I = V / R and R = V / I)
> - on another thread I mentioned that you have to see Ohms law in 3-dimensions to fully comprehend what happens when you change 1 or more parameters. I suggest you make simple spread sheet and put aforementioned equation - then change the Voltage if you vary the voltage or Wattage if you change same. There is also plenty online calculators you can play with on the web. Your coil resistance is fixed and does not change, irrespective of change in voltage in the case of a VV mod, the only thing that changes in this setup is the current. When you change the Wattage with a VW mod, you have to use both aforementioned equations to see the picture. Hope this help you.


Thanks, @johanct. I done just that, but cannot interpret the results. If the resistance does not change as @Hein510 postulates, then at a resistance of 2.2 you get:

With *VV* device at 4.8 V:
Power = 10.47273 W
Current = 2.1812 A

With *VW* device at 12 W:
Voltage = 5.13809 V
Current = 2.3355 A

Does the above data show any reason why the vape would taste burnt in the VV device, but not in the VW device?


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## Derick (4/3/14)

Here's a link to an online calculator - enter any two values and it will calculate the other two - hit 'reset' to make a different calculation


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## johan (4/3/14)

Matthee said:


> Thanks, @johanct. I done just that, but cannot interpret the results. If the resistance does not change as @Hein510 postulates, then at a resistance of 2.2 you get:
> 
> With *VV* device at 4.8 V:
> Power = 10.47273 W
> ...



Yes @Matthee, the VW mods in essence use a micro processor to do the calculations and might change a combination of voltage as well as current limiting, depended on user settings - it will however vary from manufacturer to manufacturer.


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## vaalboy (4/3/14)

Well this thread got me thinking so I upped my MVP to 11watts (was vaping at 7 using the same juice and tank previously) - no burnt taste!

What I have noticed is that I have to set my MVP at 1w higher than my zmax to get a similar vape - go figure.


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## johan (4/3/14)

Different manufacturers will program the their micro processors differently with different results.


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## johan (4/3/14)

This freeware is not just for coil building but will also indicate various parameters as you change voltage and/or wattage; see post http://www.ecigssa.co.za/index.php?...ng-wick-and-coil-setup.246/page-49#post-20993 for download site.

Reactions: Winner 1


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## Hein510 (4/3/14)

ok so why doesnt it give you a burnt taste while vaping at 20Watts or 30Watts (I think with the DNA30) on a VW?

30Watts on a 2.2Ohms coils is like 8.12Volts and 3.69Amps!

With the VV I'm using the PT2 on 4Volts with 2.2Ohms coil and it burns, thats only 7Watts and 1.8Amps
On the SVD I'm using the same PT2 with the same 2.2Ohms coil and it doesnt burn at 15Watts, thats 5.7Volts and 2.6Amps


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## SunRam (4/3/14)

Hein510 said:


> ok so why doesnt it give you a burnt taste while vaping at 20Watts or 30Watts (I think with the DNA30) on a VW?
> 
> 30Watts on a 2.2Ohms coils is like 8.12Volts and 3.69Amps!
> 
> ...


For me, PT coils are optimal around 5-7W. I would suppose that your SVD is defective, or not putting out the correct W. Any PT2 will taste burnt over 9W, and for sure over 10W, since it's a single coil with poor direct airflow over the coil.
10-12W is designed for dual coils, and 12W plus is designed for RBA's and RDA's (rebuildables) where you have MUCH better control over the airflow directly over the coil.


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## johan (4/3/14)

Hein510 said:


> ok so why doesnt it give you a burnt taste while vaping at 20Watts or 30Watts (I think with the DNA30) on a VW?
> 
> 30Watts on a 2.2Ohms coils is like 8.12Volts and 3.69Amps!
> 
> ...



I'l try to be not to technical: VV works on voltage change only; meaning that the current (amps) will increase as much as the unit can provide when you increase the voltage - the output wave shape is more/less linear (straight line) - 100% chance of too hot a coil, dried out wick and hence burnt taste. VW devices make use of PWM (pulse width modulation); when you increase the power (wattage) the voltage as well as current (amps) change, but the wave shape is a block type (ON-OFF-ON-OFF @ high frequency) - in the OFF periods the coil receives no power (volts and amps), minimizing overheated coil and some assistance in keeping the wick moist, hence no burnt taste (obviously to a point, depending on coil resistance).

Reactions: Like 1 | Winner 2


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## johan (4/3/14)

I'm busy at the moment fixing a couple of devices - when finished, I will capture some wave shapes of different devices on the oscilloscope and put it up on this thread - it will make explaining my previous explanation more visual.

Reactions: Like 1 | Winner 1


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## devdev (4/3/14)

I have noticed something similar with my PT2's compared to custom made coils.

Let's say I have a PT2 running at 2.2ohms and I have a home made coil running in an RBA at 2.2ohms.

I can crank to about 8.5w with the PT2 coil before it tastes burnt, whereas with the RBA I can crank to 15W and it doesn't taste burnt.

Thinking carefully about it, I realised that the wick on the PT2 is probably the bottleneck. 

It may not be able to absorb more liquid quickly enough, so the burnt taste actually comes from the heating of the wick, flavour wicks and any gunk that's built up on the atomiser before the wick has absorbed more juice.

On the RBA with the monster cotton wick I am using, the juice is replaced as fast as it gets burnt.

So in other words, on the PT2 coil the burnt flavour is the same you would get from a dry hit (burnt wicks & gunk from atomiser).

I think the wattage being turned up too high burns the juice faster than it gets replaced with some coils.

If i turn my SVD to VV and crank it to 6.0v, there is no burnt taste on the custom made coil, so I don't think the issue is about VV or VW, rather about how fast the juice gets to the coil through the wick


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## Hein510 (4/3/14)

johanct said:


> I'l try to be not to technical: VV works on voltage change only; meaning that the current (amps) will increase as much as the unit can provide when you increase the voltage - the output wave shape is more/less linear (straight line) - 100% chance of too hot a coil, dried out wick and hence burnt taste. VW devices make use of PWM (pulse width modulation); when you increase the power (wattage) the voltage as well as current (amps) change, but the wave shape is a block type (ON-OFF-ON-OFF @ high frequency) - in the OFF periods the coil receives no power (volts and amps), minimizing overheated coil and some assistance in keeping the wick moist, hence no burnt taste (obviously to a point, depending on coil resistance).


Now THATS an answer!!! Thanx @johanct

Reactions: Agree 1


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## Silver (5/3/14)

Devdev, i hear you and i think your points are right, however, the original poster is using the same coil on both devices.


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