question about vv and vw

[jkais3r]

Ok. I understand variable voltage, and wattage. In a vv device the ampacity is set by the battery, in a vw device you set both, essentially, because from what I understand because you can vape at x volts on y watts, where the watts is actually determining the ampacity from the set volts. Right?

So, by the above electrical logic, vv devices are also vw devices without the option to alter the ampacity, correct?

Secondly, I've seen people say that the coil's resistance may have different effects when only using a variable voltage, and that vw is more consistent. I do not see why this would take place because resistance is not included in a basic power equation, p=ei, voltage equation is e=ir, where r is resistance. I'm assuming that either way we are setting our devices to the source power, and after that the voltage/power being used by the load (coil) would be different due to the resistance. But, why would this have a different effect on your vv device at the same wattage (if you knew the amps it's possible), as your vw device? Or am I just missing something?

Question is aimed more towards lower end devices (twist/mvp2), just would like to confirm that a vv and vw device have the same effect, while vv is just lacking an ampacity selection.

I suppose the difference between the two would be with vv setting your wattage higher would result in a hotter vape, whereas with a vw device you could leave the voltage down and would result in a cooler vape?

 

[AttyPops]

This is how VW works:

(Remember the e-cig has a little computer in it)

1) Read the ohms of the attached coil.
2) Get the desired wattage setting W from the user's last selection.
3) Compute the voltage required to get Watts (W) with Ohms from step 1.
4) Set voltage to that.
5) Turn on atomizer connector while button is down.

Overly simplified, but essentially correct for discussion purposes. It may actually loop through 1-5 several times per second. IDK.

For VV it is:
1) Get the last setting for voltage and set the voltage to that.
2) Turn on atomizer connector while button is held down.

The amp draw is a function of the current battery voltage and the desired voltage and the ohms and the efficiency of the booster circuit. Any inability of the battery to deliver the amps at it's current voltage results in a voltage drop.

 

[wonner]

VV = you set the volts, based on the resistance of the head, to produce a certain wattage.

VW = you set the watts and the device figures out the volts based on the resistance of the head.

Both get you to the same place.

 

[jkais3r]

Wonner- I completely agree.

Attypops- I understand now. I guess I didn't realize how actually well engineered these things are. I'm sold, ordering a new toy soon.

 

[Topwater Elvis]

Using a vw device you can not adjust both V and W, you set one or the other.

It is either in V mode or W mode.

 

[jkais3r]

Ah, well that makes sense then. Thank you topwater.

I suppose the only question left is: Is there a difference between having a vv device and vw device set to the same wattage using the same clearomizer/atty?

 

[AttyPops]

Wonner- I completely agree.

Attypops- I assume you're talking higher end devices? I guess I was asking about basic devices, such as let's say a twist and an mvp2, or does something that has vw like the mvp2 ignore your voltage setting and just go by wattage?

I was talking about the logic of ANY VW device. Functionally, they could have some form of wattage feedback circuit...IDK. But logically/conceptually, that's how it works. So if it has VW, it also has VV, but may not give VV options to the user. AKA...a VW-only device just doesn't have a VV option on the menu. It can do VV by definition.

Bottom line is that VW devices have to be able to read the ohms of the coil. They usually allow you to see the result too (may as well).

VV devices need no such thing built in.

 

[ConradM]

Wonner- I completely agree.

Attypops- I assume you're talking higher end devices? I guess I was asking about basic devices, such as let's say a twist and an mvp2, or does something that has vw like the mvp2 ignore your voltage setting and just go by wattage?

Vamo's have VW and they're $30 on fasttech.

 

[jkais3r]

I was talking about the logic of ANY VW device. Functionally, they could have some form of wattage feedback circuit...IDK. But logically/conceptually, that's how it works. So if it has VW, it also has VV, but may not give VV options to the user. AKA...a VW-only device just doesn't have a VV option on the menu. It can do VV by definition.

Bottom line is that VW devices have to be able to read the ohms of the coil. They usually allow you to see the result too (may as well).

VV devices need no such thing built in.

Well, you pretty well blew my theories about the inner workings of vw e-cigs out the window. Thank you. Did not also realize that they account for voltage drop across the load and, I don't know if this is right, but put out a higher voltage so that the wattage that returns back on the negative terminal is the set wattage?

 

[Wickeddeuce]

the advantage of vw over vv is this...

i like vaping my white chocolate peppermint mocha at 10 watts, if i set my vw to 10 watts, and i change the coil and it has a lower resistance the device will adjust to stay at 10 watts... essentially vw is a way to be lazy and not figure out what volts you need to be at 10 watts...

there is another advantage that i read somewhere about how vw has another function to it... but that above is the absolute simplest...

 

[AttyPops]

Well, you pretty well blew my theories about the inner workings of vw e-cigs out the window. Thank you. Did not also realize that they account for voltage drop across the load and, I don't know if this is right, but put out a higher voltage so that the wattage that returns back on the negative terminal is the set wattage?

That's what I meant when I said IDK if they have actual wattage feedback or not. Active monitoring. I Don't Know.

But they at least read the ohms and compute the required voltage. How often they adjust it and monitor it...IDK. May be implementation dependent too.

There's always a voltage drop across any resistance. So it may be monitoring what's going into the load.

 

[Fergie]

This is how VW works:

(Remember the e-cig has a little computer in it)

1) Read the ohms of the attached coil.
2) Get the desired wattage setting W from the user's last selection.
3) Compute the voltage required to get Watts (W) with Ohms from step 1.
4) Set voltage to that.
5) Turn on atomizer connector while button is down.

Overly simplified, but essentially correct for discussion purposes. It may actually loop through 1-5 several times per second. IDK.

For VV it is:
1) Get the last setting for voltage and set the voltage to that.
2) Turn on atomizer connector while button is held down.

The amp draw is a function of the current battery voltage and the desired voltage and the ohms and the efficiency of the booster circuit. Any inability of the battery to deliver the amps at it's current voltage results in a voltage drop.

That's how I see it, however some seem to get the VV part wrong.

 

[jkais3r]

the advantage of vw over vv is this...

i like vaping my white chocolate peppermint mocha at 10 watts, if i set my vw to 10 watts, and i change the coil and it has a lower resistance the device will adjust to stay at 10 watts... essentially vw is a way to be lazy and not figure out what volts you need to be at 10 watts...

there is another advantage that i read somewhere about how vw has another function to it... but that above is the absolute simplest...

So what you are saying is that I really need to order up that vw device I've been eyeing up.

 

[Wickeddeuce]

lol, i like the vw... i havent even used the vv function on my svd... lol... i keep it set on vw... and adjust as needed... it only adjusts in .5 increments but... i dont mind... .5 at a time i can warm it up, cool it down, more vapor, less vapor, more taste, less taste, all while adjusting it...

and i know where i am at exact wattage... my favorite thing, is if i use my ego v v2 (just variable voltage) i know what watts i want to be near and can figure out what volts i need to use... though i havent touched my ego v v2 since i got my svd... its my emergency device...

 

[Bunnykiller]

VV you set the voltage and it stays at that voltage if you coils ohms change the voltage stays the same therefore youre wattage changes
VW you set the wattage and as youre coil ohms change the voltage changes to keep up with the wattage you set ( if your coil goes higher in ohms, the voltage automatically increases to keep the wattage the same)

 

[higskies]

VW is a more consistent vape than VV. I have a VAMO V3 and Smoktech SID and keep them both around 12.5 watts. I keep my atomizers around 1.8ohms. I don't even compute voltage anymore. These are the vaporizers I carry around with me at work, errands, in the car, etc. Set and forget...

 

[Bigguyjake]

Yeah VW has the "set and forget it" mentality. Also, a lot of coils can be mislabel. I have had a few, I find it is easier to maintain consistency with VW, although when I am feeling like it I choose VV to do some fine tuning. My MVP 2.0 only changes the wattage in .5 increments, some times its good to use the VV to get a more precise setting. IDK VW has been working just fine for me though.

 

[Bigguyjake]

Also check this out, great explanation! http://www.e-cigarette-forum.com/fo...e-voltage-vs-variable-wattage-better-why.html

 

[RaceGun59]

The set and forget of VW is good if you use the same juice in all your tanks. I use VV because I find that differant juices vape better at differant levels. The 3 ProTanks I have in rotation that have coils that ohm out at 2.5 and I adjust my voltage according to the juice. My B&M mix Smarties runs best at 4.2 V, but my Redbull runs better at 4.4 V. I'm always making adjustments as I vape so the important part is the "varible", whether it be voltage ot wattage.

 

[Chago]

I was explaining VV/VW to someone a while back and used this analogy.

Think of VV as the throttle pedal in your car. You adjust as necessary to maintain a constant speed, regardless of the grade of the road. A lower resistance Atty would be like driving down a hill. Wouldn't need as much gas to keep your speed. Now, climbing the hill on the other side of the valley will need more throttle, as a higher resistance Atty needs more voltage.

Then we have cruise control (variable wattage). Set the cruise for 8 watts and let the car (mod) figure out which road (atty) it's driving on.

Just have to watch out for those crazy, cloud chasing, sub-ohm, speed freaks. Or else they'll blow your doors off as they barrel down the road at 110mph. Wide open until the gas tank is empty! Buncha hooligans!