Watts do not matter. Its all about wire temp. Read on

[cckk]

Here: http://www.e-cigarette-forum.com/fo...blem-effectiveness-device-5.html#post10313352 Senior Member sailense published an elegant and coherent explanation of the phenomenon concerning VAMO V2 which drains the batteries extensively in mode No. 2 (RMS). I just started the next batch of the tests but it looks that my practical results will be compatible with sailense’s hypothesis.

 

[cckk]

gdeal, sailense, MikeE3, JeremyR, et al.

I performed the consecutive tests of VAMO V2. As before I used AGA-T2 atomizer, Kanthal D 0.25 mm (30 AWG) wire, and mesh 400 25×35 mm (1×1⅜″). The coil used in those tests had 6 wraps and produced 1.8 Ω resistance. Before each measurement I stabilized the coil at 1.8 Ω.

First I used VAMO in No.1 mode with preset 6.0 W to test the battery draining. I was able to vape the entire 3 ml tank of a liquid using 18650 3400 mAh battery, and the device drained the battery to 3.4 V. Previously I managed to achieve a similar result in No. 1 mode with preset voltage. So it seems that in No. 1 mode the device doesn’t drain the battery too much.

So far I didn’t test VAMO in No. 2 mode with preset voltage. I suspect that No. 2 mode drains the battery extensively in that mode so I have to wait now until my battery “B” will be ready to use it in that last test because this is my battery for tests in VAMO. I’m aware that better method of testing is to use at least 4 new batteries – the other one for each type of the test – and cycle each of them 10 times. But I’m not enough wealthy to kill two batteries testing them on VAMO in No. 2 mode and I’m not enough jobless to perform these 40 tests.

Then I performed the complete set of the tests of the real voltage of the device in both VAMO modes with both preset types. I repeated two tests described in post #137 because now I stabilized the coil resistance before each measurement. It seems also that I did those measurements now the other way than before because the new ranges are narrower.

No. 1 mode, 1.8 Ω
voltage set	wattage counted	voltage measured	average voltage	real wattage
3.0 V	5.00 W	2.88–2.90 V	2.89 V	4.64 W
3.1 V	5.34 W	2.98–3.02 V	3.00 V	5.00 W
3.2 V	5.67 W	3.12 V	3.12 V	5.41 W
3.3 V	6.05 W	3.22–3.23 V	3.23 V	5.80 W
3.4 V	6.42 W	3.35–3.36 V	3.36 V	6.27 W
3.5 V	6.81 W	3.41–3.43 V	3.42 V	6.50 W
3.6 V	7.20 W	3.53–3.54 V	3.54 V	6.96 W
3.7 V	7.61 W	3.67–3.69 V	3.68 V	7.52 W

No. 1 mode, 1.8 Ω
wattage set	voltage counted	voltage measured	average voltage	real wattage
5.0 W	3.00 V	2.84–2.92 V	2.88 V	4.61 W
5.5 W	3.15 V	3.15–3.17 V	3.16 V	5.55 W
6.0 W	3.29 V	3.16–3.20 V	3.18 V	5.62 W
6.5 W	3.42 V	3.42–3.46 V	3.44 V	6.57 W
7.0 W	3.55 V	3.27–3.32 V	3.30 V	6.05 W
7.5 W	3.67 V	3.58–3.64 V	3.61 V	7.24 W
8.0 W	3.79 V	3.69–3.72 V	3.71 V	7.65 W

No. 2 mode, 1.8 Ω
voltage set	wattage counted	voltage measured	average voltage	real wattage
3.0 V	5.00 W	1.67–1.73 V	1.70 V	1.61 W
3.1 V	5.34 W	1.77–1.79 V	1.78 V	1.76 W
3.2 V	5.67 W	1.93–1.96 V	1.95 V	2.11 W
3.3 V	6.05 W	2.04–2.06 V	2.05 V	2.33 W
3.4 V	6.42 W	2.18–2.19 V	2.19 V	2.66 W
3.5 V	6.81 W	2.31–2.33 V	2.32 V	2.99 W
3.6 V	7.20 W	2.47–2.48 V	2.48 V	3.42 W
3.7 V	7.61 W	2.62–2.63 V	2.63 V	3.84 W

No. 2 mode, 1.8 Ω
wattage set	voltage counted	voltage measured	average voltage	real wattage
5.0 W	3.00 V	1.72–1.74 V	1.73 V	1.66 W
5.5 W	3.15 V	1.83–1.85 V	1.84 V	1.88 W
6.0 W	3.29 V	2.05–2.06 V	2.06 V	2.36 W
6.5 W	3.42 V	2.49–2.52 V	2.51 V	3.50 W
7.0 W	3.55 V	2.34–2.36 V	2.35 V	3.07 W
7.5 W	3.67 V	2.47–2.54 V	2.51 V	3.50 W
8.0 W	3.79 V	2.60–2.73 V	2.67 V	3.96 W

According to the tables No. 1 mode is almost perfectly reliable while No. 2 mode is completely unreliable (and it kills the batteries). So I see two possibilities: either RMS implementation in No. 2 mode is very poor in the case of VAMO V2 or No. 2 mode is in fact AVG one while No. 1 mode is in fact RMS one. Anyway the only useful VAMO V2 mode is No. 1.

 

[gdeal]

cckk

From the data, no2 mode for VAMO is not accurate in what it reports. Obvious from data right? So the electronics for no2 are either down throttling Volts and/or are creating a battery drain to do no2 mode that is not reflected in the RMS calculation and subsequent voltage delivery.

But since batt life is less than mode 1 on a equivalent volt display basis, it appears that mode 2 is really just creating an extra drain on batteries and not reporting/calculating for it.

Conclusion: inferior electronics/design?

 

[Mad Scientist]

A quick question about these calculations: how were the actual voltages delivered by the device measured? These measurements are central to the actual wattage delivered calculations.

 

[cckk]

Conclusion: inferior electronics/design?

Probably: yes.

From my point of view the reason doesn’t matter because I can’t change it – I can merely manage with its results. I know that the most reliable is No. 1 mode with the preset voltage so I use VAMO with these settings. I even started to like VAMO V2 with AGA-T2 because I can use them now almost the same way as I use The Natural with RSST.

That doesn’t mean that I can reproduce the taste got from RSST using AGA-T2. It isn’t possible but I stopped to worry with that. Two different devices used with the same liquid produce different taste. That’s good because I have a wider range. The same liquid used in the same device tastes different at the beginning of the tank, in the middle, and at the end. It tastes different each day as well.

I don’t believe also in so called “sweet spots”. The same coffee prepared with the same espresso maker using the same method tastes different each time. Once a month it tastes really great. Three times a month it tastes really poor. From 150 to 200 times a month its taste in somewhere in the middle between the great one and the poor one. It tastes different also at the beginning of the cup, in the middle, and near the end.

A quick question about these calculations: how were the actual voltages delivered by the device measured? These measurements are central to the actual wattage delivered calculations.

I don’t understand your question. The battery was inside VAMO V2. The AGA-T2 atomizer was on top of VAMO. The coil was connected to the negative and positive posts of AGA-T2. I attached the multimeter test leads to the negative and positive posts and fired the device. So the electrons flew from the battery negative electrode, through the VAMO V2 body, the body of AGA-T2 atomizer, the bottom post of AGA-T2, the coil made out of the resistance wire, and the center post of AGA-T2 to the battery positive electrode.

 

[Mad Scientist]

Your results just don't make sense to me. Maybe I am reading them incorrectly. According to your chart, mode 2 set at 8 watts delivers less than 4 watts actual. Unless the Vamo is broken, that can't be right. 4 watts would barely vape. Are you sure you have calculated correctly for the PWM output of the device?

If I set my Vamo to 8 watts in mode 2 I get a vape comparable to a "real" 8 watt vape on all my other vv devices (comparable to 4 volts into 2 ohms). 4 actual watts is barely a detectable vape. See what I mean?

 

[sailense]

I really applaud your approach to this, cckk.

However, I think your multimeter is at fault here. Most multimeters will always read the avg from a PWM source and that would explain why you're seeing more accurate numbers for the avg settings.

Let's look at the 3v setting. Here's what we know:
Max pulse voltage on Vamo: 6v
Duty Cycle: 33hz, approx. 30ms per duty cycle

So, for an avg setting of 3v, it's pretty easy to calculate the avg. It's just half the duty cycle, or 15ms.

But for an rms setting of 3v, it gets a bit tricky. Here's the formula (source: What are the peak and RMS values of the voltage of a pulse-width-modulated signal):
Vrms = ((C × V1^2) + ((1 - C) × V2^2))^0.5

Where:
V1 = Top voltage, 6v
V2 = Bottom voltage, 0v
C = Duty Cycle (Edited to add: In the formula, C is set as a percentage of 1 duty cycle. So a 15ms pulse on a 30ms duty cycle would give 0.5 as a value for C in the formula.)

Solving it out, at a 15ms (or 0.5C) duty cycle, the rms comes out to 4.24v. If we solve for what the duty cycle should be for 3v rms, we come up with 7.5ms (or 0.25C). At a 7.5ms duty cycle, the avg reading would be 1.5v. That's close to the 1.7v measured on No2 setting at 3v and would indicate that the meter is indeed reading the avg rather than the rms voltage.

Note: I plugged the formulas and the values into a math program, so please let me know if I've made any errors in calculation.

 

[sailense]

As further evidence, here's a screenshot of the Phil Busardo video with the details of the Vamo on an oscilloscope:

You can see some detail such as:
Period: 30ms
Frequency: 33.28Hz
avg Voltage (listed as Mean): 3.117v
Peak (listed as Vp): 5.920V (pretty close to the theoretical 6v peak of the Vamo. I'm guessing the difference is due to voltage sag)
rms Voltage (listed as Cycrms Vk): 4.054v
Duty Cycle: between 12.4ms and 17.6ms (this matches up fairly closely with our formula)

From the video, he notes that this is for a 3ohm carto with the 4v setting. At that setting, you can see the Vrms is 4.054v and the Vavg is 3.117v.

So, a meter reading only avg would see near 4V on the No1 setting and only around 3.117v on the No2 setting.

I don't suppose you'd be willing to do a test run at 4v to see if that is the case with your meter?

 

[cckk]

Mad Scientist,

It seems that sailense explained what may be wrong with my results. My multimeter measures the average voltages. As a result the measurements are correct when VAMO works in AVG mode but wrong when it works in RMS mode.

sailense,

So I built the castles in the air and now they’re fell into ruin. Fortunately my final conclusion remains the same: VAMO is more friendly for the batteries in No. 1 mode. I suspect that VAMO is also a bit more friendly for the batteries in the voltage preset mode but to prove that the extensive tests would be necessary and I rather don’t plan to run them. Anyway I use VAMO in No. 1 mode usually with the preset voltage and sometimes with the preset wattage.

Before buying some new batteries I have to be sure that VAMO in No. 1 mode is secure for the batteries. After my last tests I own just one healthy battery so some shopping will be necessary pretty soon.

Thank you very much for your kind assistance and detailed explanations.

 

[Mad Scientist]

The battery life results are still very interesting.

 

[cckk]

Mad Scientist,

The battery life results are still very interesting.

Interesting? Yes. Reliable? Partially.

As I declared in the concurrent thread my vaping style is the following:

1. I put fully charged 18650 3400 mAh battery into a device.

2. I fill the entire 3 ml tank with a liquid.

3. My goal is to vape the entire tank using one battery without discharging it too much.

I use moderate resistances: about 1.8–1.9 Ω. With my Kanthal 0.25 mm (30 AWG) wire and RSST or AGA-T2 atomizers they require 5–6 wraps. The taste of the liquids is good with those configurations. The used currents are moderate. My only concern was the batteries life in the case of VAMO V2. After the tests I know now that only No. 1 mode is safe for the batteries – at least with the fore-mentioned vaping style.

 

[dr g]

Shouldn't this vamo stuff be broken out into its own thread?

 

[sailense]

Mad Scientist,

sailense,

So I built the castles in the air and now they’re fell into ruin. Fortunately my final conclusion remains the same: VAMO is more friendly for the batteries in No. 1 mode. I suspect that VAMO is also a bit more friendly for the batteries in the voltage preset mode but to prove that the extensive tests would be necessary and I rather don’t plan to run them. Anyway I use VAMO in No. 1 mode usually with the preset voltage and sometimes with the preset wattage.

Before buying some new batteries I have to be sure that VAMO in No. 1 mode is secure for the batteries. After my last tests I own just one healthy battery so some shopping will be necessary pretty soon.

Thank you very much for your kind assistance and detailed explanations.

I still think there's value in your tests, so don't worry about "castles in the air". It's always good to have somebody do the ground work and keep us honest with the difference in what we theorize and how things work in real life. So cheers for that.

 

[gdeal]

Shouldn't this vamo stuff be broken out into its own thread?

I agree...seems like it has gone a bit too OT. (good discussion though guys....)

 

[BJ43]

Shouldn't this vamo stuff be broken out into its own thread?

Here:
VAMO

 

[Mad Scientist]

Shouldn't this vamo stuff be broken out into its own thread?

Dr. g, yup, this thread has my gray matter firing again. Is it wire temp or is it really the point at which phase change occurs lol.

So if we break down what's going on, my thoughts at this point are that the thinner wire (with less surface area) causes phase change in less time (actually fewer Joules in the thin wire will result in phase change at the wire surface than a thicker wire with more surface area) and as soon as phase change occurs, the vaporized juice surrounding the wire insulates the liquid juice from the wire, and it may thus get too hot and burn; if it does not burn it will get hotter -- hotter than the boiling point of the juice. Trying to create an ideal atomizer is not watts or wire temp, but the ideal amount of power in watts for the total surface area of the coil / liquid juice the wick can supply in contact for a "normal" vape time, assuming away power limitations of whatever powers the coil (at least for now).

Total watts and wire temp are really both just proxies for the really interesting point of causing phase change of the amount of juice in contact with the coil without exceeding the temp at which the juice burns. Up to a point (at which most would find it to be "too much") more is better.

And then there is airflow... Lol.

 

[sailense]

Dr. g, yup, this thread has my gray matter firing again. Is it wire temp or is it really the point at which phase change occurs lol.

So if we break down what's going on, my thoughts at this point are that the thinner wire (with less surface area) causes phase change in less time (actually fewer Joules in the thin wire will result in phase change at the wire surface than a thicker wire with more surface area) and as soon as phase change occurs, the vaporized juice surrounding the wire insulates the liquid juice from the wire, and it may thus get too hot and burn; if it does not burn it will get hotter -- hotter than the boiling point of the juice. Trying to create an ideal atomizer is not watts or wire temp, but the ideal amount of power in watts for the total surface area of the coil / liquid juice the wick can supply in contact for a "normal" vape time, assuming away power limitations of whatever powers the coil (at least for now).

This is in line with my theory of why more air flow helps with vapor production. Drawing the already vaporized liquid away from the coil will prevent saturation and provide more vapor. There is also a point of diminishing returns as too much airflow will dilute the vapor.

So, I agree with your points, but I also think that air flow should also be a consideration.

 

[dr g]

Dr. g, yup, this thread has my gray matter firing again. Is it wire temp or is it really the point at which phase change occurs lol.

So if we break down what's going on, my thoughts at this point are that the thinner wire (with less surface area) causes phase change in less time (actually fewer Joules in the thin wire will result in phase change at the wire surface than a thicker wire with more surface area) and as soon as phase change occurs, the vaporized juice surrounding the wire insulates the liquid juice from the wire, and it may thus get too hot and burn; if it does not burn it will get hotter -- hotter than the boiling point of the juice. Trying to create an ideal atomizer is not watts or wire temp, but the ideal amount of power in watts for the total surface area of the coil / liquid juice the wick can supply in contact for a "normal" vape time, assuming away power limitations of whatever powers the coil (at least for now).

Total watts and wire temp are really both just proxies for the really interesting point of causing phase change of the amount of juice in contact with the coil without exceeding the temp at which the juice burns. Up to a point (at which most would find it to be "too much") more is better.

And then there is airflow... Lol.

Now you're getting it

The fact that we're basically flash boiling the liquid is a big factor which makes the wire size very significant.

 

[Mad Scientist]

This is in line with my theory of why more air flow helps with vapor production. Drawing the already vaporized liquid away from the coil will prevent saturation and provide more vapor. There is also a point of diminishing returns as too much airflow will dilute the vapor.

So, I agree with your points, but I also think that air flow should also be a consideration.

Yes, definitely another factor to consider and another complication.

 

[jasl90]

Getting close but not exactly hitting it on the head...
The thicker the wire the more amperage it can handle without over heating. The thinner the wire the hotter it will get under a given amp load.
This doesn't just apply to the world of atomizers... The wiring in your home for example... Codes mandate that the wire be of a specified gauge or greater.
Also, the resistors we find in all of our electronics all have wattage ratings. The teeny tiny ones are only a fraction of a watt while the larger ones may be a watt or more and the big ones, embedded in big aluminum heat sync blocks can be rated to over 100 watts.

So, holding all other things equal (ohms, volts & amps), the thinner the wire is, the hotter it will get...
Which also means, the thicker the wire is, the more power it will need to reach a given temperature.