The Great Debate... VV vs VW!

[junkman]

I'm not the one that misunderstands anything. You, my friend, are the one off track!

A 1.5 ohm dual-coil cart actually has two 3 ohm coils connected in parallel inside of it. Their effective resistance, or the resistance the Vamo sees, is 1.5 ohms. Hence, if you connect a Vamo set for 8 watts (VW) to the 1.5 ohm dual-coil cart, the Vamo will attempt to adjust to 3.46v.

Herein lies the problem. The voltage being supplied by the Vamo is actually too low because it's getting "fooled" into thinking it's looking at a single 1.5 ohm coil. Because there are actually two coils (two current paths) inside the dual-coil cart, each coil actually only dissipates 1/2 the total power. This means that each coil is only heating up to approx 4 watts.

Overall dissipated power remains the same for the Vamo, but because each coil is only heating to 1/2, what do you think is happening to how the juice vaporizes? I can tell you... it's going to be a weak(er) vape.

Anyways, hopefully you can understand why I use my Vamo in VV mode, and not the "apparently preferred" VW mode. You know, every user has his own reasons.

Peace!

Thanks for the explanation. As I said, I haven't used the dual coils, so I figured something was different.

But let me ask you, because I don't know, is the fact that the vamo thinks it is 1/2 the ohms limiting the amount of power you can apply? i.e., you need 18 watts and it only lets you go to 15? Does VV let you get the equivalent of setting the VAMO at 18 watts?

That would be a very good reason to prefer VV. I guess they could overcome that with some software - maybe evic style, where you could inform the PV that you are using dual coil, and therefore it make the necessary adjustments.

Thanks! Looking forward to answers.

 

[nahoku]

Thanks for the explanation. As I said, I haven't used the dual coils, so I figured something was different.

But let me ask you, because I don't know, is the fact that the vamo thinks it is 1/2 the ohms limiting the amount of power you can apply? i.e., you need 18 watts and it only lets you go to 15? Does VV let you get the equivalent of setting the VAMO at 18 watts?

That would be a very good reason to prefer VV. I guess they could overcome that with some software - maybe evic style, where you could inform the PV that you are using dual coil, and therefore it make the necessary adjustments.

Thanks! Looking forward to answers.

The Vamo is limited no matter what mode you're in. You're not going to get 18 watts out of a 15 watt device... unless you hack it!

From what I've seen (reviews), the cut off voltage (where the Vamo starts suffering) for 1.5 ohm carts, whether dual or single, is around 4.2 - 4.5v. This means, no matter what you do, you're only going to be able to achieve approx 6.x watts for each coil in a 1.5 ohm dual-coil cart. This is lower than optimal for some, but it works fine for me. The problem is really not the Vamo as it can handle single coils just fine, it's only when a dual-coil cart is attached to it while in VW mode.

And, it's not just the Vamo. If you "kick" a mechanical mod and connect a dual-coil to it, you'll see the same thing.

I think one review showed that if you stack batteries in a Vamo, you can push the cut off voltage to 6 volts on a 1.5 ohm cart. I tried to stack once, but found that my LCD screen became really bright, so I didn't pursue it. I'm not sure what the electronics can handle so it's not worth it to me. By the way, I'm a retired engineer, so I tend to play things safe unless I know for sure. Now, if I had a schematic, that would be a different story!

I only use VV because it's convenient for me. Maybe when I get rid of all these 1.5 ohm dual-coils things will change... that might take a year though!

 

[peraspera]

I think one review showed that if you stack batteries in a Vamo, you can push the cut off voltage to 6 volts on a 1.5 ohm cart. I tried to stack once, but found that my LCD screen became really bright, so I didn't pursue it. I'm not sure what the electronics can handle so it's not worth it to me. By the way, I'm a retired engineer, so I tend to play things safe unless I know for sure. Now, if I had a schematic, that would be a different story!!

I've been running stacked Efest 18350s in my VAMO since the middle of December with no ill effects at all. However, I do play by the battery stacking rules.

The batteries have always been used paired, I alternate the top and bottom positions with each use and frequently check the voltage before using the batteries. I use an intelligent charger and rest batteries before using as well as charging.

I've only run the batteries down to the VAMO cutoff a couple of times to see if it worked. They usually get charged at about half power.

 

[nahoku]

I've been running stacked Efest 18350s in my VAMO since the middle of December with no ill effects at all. However, I do play by the battery stacking rules.

The batteries have always been used paired, I alternate the top and bottom positions with each use and frequently check the voltage before using the batteries. I use an intelligent charger and rest batteries before using as well as charging.

I've only run the batteries down to the VAMO cutoff a couple of times to see if it worked. They usually get charged at about half power.

Yah, I've read many posts about people stacking. When I stacked, I did it with fully/newly charged batteries and I read the rules too, although the rules don't make much sense to me beyond common sense.

A lot of electronic devices, like op-amps, can run at various input voltages. Some can vary from 5 - 12v inputs (common). I don't know what's inside the Vamo, but I would guess that it might be able to handle going from 4.2 to 8.4. I just don't know and some vendors recommend against it. The only reason I attempted stacking was to see what would happen. Nothing gained, nothing lost for me to run a single 18650 vs two 18350's at risk of blowing my cheap Vamo. Still $50 to replace is not worth it to me. I may not be as lucky as some folks!

 

[peraspera]

I would agree that there is little point in going to the bother of stacking batteries unless you need the power. I've found it somewhat handy when ohms were jumping up when rebuilding my AGA-T2s. However, I'm a low power vapor and pretty much over rebuilding stuff since I got my AMP Tanks so when those batteries bite the dust I probably won't be stacking any more.

I would take vendor warnings not to stack batteries in the VAMO with a boatload of salt. Some seem to be dumber than a pile of rocks about batteries and the manufacturer indicates stacked mode as an option with no warnings.

Phil Busardo is an engineer. His VAMO review shows the power output for stacked batteries but he doesn't specifically address your concerns about how the electronics might be able to handle the increased power output longterm.

 

[nahoku]

I would take vendor warnings not to stack batteries in the VAMO with a boatload of salt. Some seem to be dumber than a pile of rocks about batteries and the manufacturer indicates stacked mode as an option with no warnings.

This is true, but given that a lot of vendors are probably not selling the "real" Vamo, they may be warning against stacking in light of that fact.

One of my Vamo's came from a vendor that warns against stacking. Hmmm... was that tell-tale! Funny how if you read around there seems to be about 5 manufactures of the Vamo. Who knows what the heck to expect nowadays!

Peace!

 

[peraspera]

Once anything becomes popular there is always a manufacturing pile-on in China to get their piece of the pie. Usually the copies are worse than the original but sometimes they are better. I'm happy to pay a little more to a retailer who is willing to sort through the worst of the Chinese QC nonsense so I don't have to. I would not buy from a vendor who refuses to offer a warranty for using a VAMO in stacked mode.

 

[bigbells]

I'm not the one that misunderstands anything. You, my friend, are the one off track!

A 1.5 ohm dual-coil cart actually has two 3 ohm coils connected in parallel inside of it. Their effective resistance, or the resistance the Vamo sees, is 1.5 ohms. Hence, if you connect a Vamo set for 8 watts (VW) to the 1.5 ohm dual-coil cart, the Vamo will attempt to adjust to 3.46v.

Herein lies the problem. The voltage being supplied by the Vamo is actually too low because it's getting "fooled" into thinking it's looking at a single 1.5 ohm coil. Because there are actually two coils (two current paths) inside the dual-coil cart, each coil actually only dissipates 1/2 the total power. This means that each coil is only heating up to approx 4 watts.

Overall dissipated power remains the same for the Vamo, but because each coil is only heating to 1/2, what do you think is happening to how the juice vaporizes? I can tell you... it's going to be a weak(er) vape.

Anyways, hopefully you can understand why I use my Vamo in VV mode, and not the "apparently preferred" VW mode. You know, every user has his own reasons.

Peace!

I said that there is no inherent difference which makes one mode preferable to the other. I see now how that statement could have interpreted as me saying that there were no reasons for user preferences.

What I meant is that there is nothing which makes the Vamo vape any differently in one mode than it does in the other. Every voltage setting has a predetermined wattage setting and every wattage setting has a predetermined voltage setting. I don't believe I was off track in that regard, but please let me know if I was.

 

[EddardinWinter]

I like it because I have a lot of attys and only one Vamo and one eVic. So when I change heads in VW mode, I am always pretty close to my final setting. Since nearly all of my juice is 80/20 or 70/30, there is not much change in the wattage i am gonna use head to head. But I have resistors of 1.8-2.5 ohms, so the VW saves me a lot of fumbling about. Also, I like the fractional increases documented above by dam. One of the first things I noticed when playing around with my eVic was the precision adjustments.

I have checked both devices ability to read the ohms, both are nearly always within a tenth of an ohm of my NIS traced Fluke 333 multimeter. I have this multimeter calibrated every year and it is the gold standard of electrical measurements IMHO.

 

[nahoku]

I said that there is no inherent difference which makes one mode preferable to the other. That was wrong. What I meant is that there is nothing which makes the Vamo vape any differently in one mode than it does in the other. Every voltage setting has a predetermined wattage setting and every wattage setting has a predetermined voltage setting. I don't believe I was off track in that regard, but please let me know if I was.

Ok, here's your exact statement again... I bolded the word "DO" just so you wouldn't miss it... I sure didn't!

OK, but you DO have a misunderstanding of VW vs VV if you think that there is some inherent difference which makes VV preferable in your particular circumstances. There is nothing you can do with VV that you cannot do with VW, and vice versa. However, the Vamo is able to retain settings for VW, but not for VV.

Notice how you emphasize the word "DO" by capitalizing it? Why did you do that? Let me tell you why I think you did it... it was to draw my attention, and anyone else's attention reading this thread, to the fact that you strongly believe I am absolutely misunderstanding VW and VV... and not only that, but as it applies to my own particular circumstances. This is where you went off track... with me.

I have a degree in electronics engineering and have practiced it for the past 28 years, but here you are trying to convince me I don't know what I'm talking about when it comes to watts and voltage... and in this case, how it applies to dual-coil carts used on the Vamo in VW mode... which happens to be "my particular circumstance".

The Vamo absolutely does not and cannot apply the correct voltage to a dual-coil cart in VW mode because it's being "fooled" by the impedance it sees. Since this is the case, and it is, does it make any sense for me to use it in VW mode since I constantly change between several dual-coil and single coil devices? Be sure you understand the electronics and the circumstance before you answer.

What I meant is that there is nothing which makes the Vamo vape any differently in one mode than it does in the other.

There are holes in this, but I won't bother pointing them out to you.



Look, as I stated in some other post in this thread, this is not really a Vamo problem alone. This is how electronics work with parallel loads, current through those loads, and the power dissipated in those loads. This is just common stuff that a lot of people don't understand and yet they stand up and try to convince people one way or the other without technical backup. They even try to convince people that they don't know what they're talking about!

My vote for VV was based on switching between single coil devices and the 1.5 ohm dual-coil carts I use. You may not use dual coils, but I don't really care about what you use! I would never try to build a case for you to use VV, so if you want to use VW, more power to you! By the same token, I don't appreciate people who try to make me look bad because my own circumstances are not the same as theirs and they can't understand it?

Vape on!

 

[bigbells]

I was not trying to make anyone look bad, but I should have made my point in a more conversational way. I apologize that you felt insulted.

Let me ask this: Is there a wattage setting that you could use with your dual coil devices that would result in approximately the same voltage being drawn as your preferred voltage setting? If so, that's the only point I was trying to make. If not, then you're right, the electrical knowledge is beyond me.

My intent is not to promote VW over VV. My intent is to find out whether I'm correct that the Vamo and other such PVs do not vape any better in one mode than the other, and that they can be set up using either mode. I do realize that the VW settings are not mirror images of the VV settings and that switching from one to the other would yield "in between" voltage/wattage settings which could not be matched precisely in the alternate mode.

 

[nahoku]

I was not trying to make anyone look bad, but I should have made my point in a more conversational way. I apologize that you felt insulted.

Apology accepted! I also apologize for getting on you for it!

Let me ask this: Is there a wattage setting that you could use with your dual coil devices that would result in approximately the same voltage being drawn as your preferred voltage setting?

You have to remember that I don't only use dual-coil devices, but also swap in single-coil devices. If I only used dual-coil devices, and NO single coils, (or vica-versa), then I wouldn't have the problem I have with VW. However, as it is, I use both kinds... so the answer to your question is no.

In a single coil, all the power is used to heat the juice, so say we run a 1.5 ohm single coil at 3.7 volts... the resulting wattage would be 9.12 watts. The juice would be heated with a single coil running at 9 watts. It would be nice and toasty!

Now if I switch in a 1.5 ohm dual-coil and run it at the same voltage. The resulting total wattage will be 9.12 watts. However, since power is shared between the two coils, then each coil is really only heating up to 4.5 watts.

If I were to run my Vamo on say, a VW setting of 9 Watts, you can see where things would fall apart for me when swapping between single and dual coil devices.

If you really want to understand, try this experiment... Set up your Vamo to vape as you normally do. Take a hit. Next, decrease the Vamo wattage to 1/2 of what it was before, and take another hit. You have just experienced a Vamo set up in VW mode swapping between single and dual coil devices.

What I don't want is for anyone to get the wrong impression here. The Vamo can run dual-coil carts just fine, however you will have to bump up the voltage or wattage a little more to do so. How much more? That all depends on you and how you like your vaping. For me... and yes, it's just for me... I prefer to run in VV mode simply because it's easier. Sure, I could run in VW mode and also bump it up... but then, that kind of defeats the purpose of running VW, doesn't it?

My intent is not to promote VW over VV. My intent is to find out whether I'm correct that the Vamo and other such PVs do not vape any better in one mode than the other, and that they can be set up using either mode.<snip>

You are correct in saying that "PVs do not vape any better in one mode than the other". I agree. However, after reading the above, do you still think they can be set up using either mode for everything?

 

[bigbells]

What I don't want is for anyone to get the wrong impression here. The Vamo can run dual-coil carts just fine, however you will have to bump up the voltage or wattage a little more to do so. How much more? That all depends on you and how you like your vaping. For me... and yes, it's just for me... I prefer to run in VV mode simply because it's easier. Sure, I could run in VW mode and also bump it up... but then, that kind of defeats the purpose of running VW, doesn't it?

You are correct in saying that "PVs do not vape any better in one mode than the other". I agree. However, after reading the above, do you still think they can be set up using either mode for everything?

It depends what you mean by everything. I never had the intent of proposing a "set it and forget it" wattage. I vary the wattage depending on my juice, and how warm I want the vapor.

I use VW for everything, but I don't use the same number of watts for everything. However, you've taught me how dual-coil devices fool the PV. I didn't realize that was the case. I've never used a dual coil device. I did not see the relevance of dual coils to the issue until you explained, and I acknowledge being recalcitrant. Thanks!

 

[nahoku]

It depends what you mean by everything. I never had the intent of proposing a "set it and forget it" wattage. I vary the wattage depending on my juice, and how warm I want the vapor. However, you've taught me how dual-coil devices fool the PV. I didn't realize that was the case. I've never used a dual coil device. I did not see the relevance of dual coils until you explained. Thanks!

It's often funny how text can be taken out of context... especially on forums. I must have misinterpreted what you meant. The "everything" I was referring to included all devices someone might use... including dual-coils in my case. Sorry if that's not what you meant.

Beyond that, I think we're both satisfied with our own usage of the Vamo in VV or VW. However, I've learned something too during this discussion and it's a rather interesting aspect of the Vamo related to VV and VW and how it obtains/runs these modes. It probably applies to many of the cheaper PV's too. Too bad I don't have and o-scope at home to do experiments with. Gotta look into this though... but not here as it would be way off-topic.

Peace!