Vmax fibs or .. dont let the chinese do your math homework

heh, as suspected the vmax outputs nothing like what its display says.

it should be noted, these are preliminary results done with no load attached.
I did a brief test with a 2.2ohm clearo on the 3.0v output and its documented below as well..


the real voltage of importance is rms of course, ideally 3.0v on the display should be 3.0V rms out the connector.

with the rms voltage then power is v^2/R .. same as with normal DC volts, thats why it is used.


quick rundown .. these readings are taken from my oscilloscope which has proven itself to be very accurate against my meter, which is just maths, meter was not 'adjusted' to match the readings, they came out correct

FWIW .. i haven't got the meter to work with the vmax properly yet, it will ..

Vmax 3.0v
battery 8.08v
duty cycle 33.3%
freq 700.93Hz
Vrms 4.50V
Vaverage 2.48V
multimeter (fluke 77) says 2.799V

Vmax 3.0v (THIS TEST UNDER LOAD WITH A CLEARO)
battery 6.80v
duty cycle 45.8%
freq 738.93Hz
Vrms 4.05V
Vaverage 2.24V
multimeter (fluke 77) says 2.495V


Vmax 4.0v
battery 8.08v
duty cycle 50.0%
freq 1050Hz
Vrms 5.70V
Vaverage 3.92V
multimeter (fluke 77) says 3.89V

note .. the duty cycle is a continually changing thing, what the vmax seems to do is always turn off for about 0.5mS
but it turns on in 2 lengths .. either 1mS or 1.5mS, a higher voltage setting has more of the longer pulses.
I need to rethink some of the way i do things in my meter to accurately show this.
this also throws out the duty cycle and frequency display on the CRO as its alway shifting, depends on which pulse and the sequence of short and long pulses what it reads.. the rms voltage however is rock solid, thats a simpler function of adding up all the sample voltages.

Vmax 5.0v
battery 8.08v
duty cycle 63.9%
freq 8133Hz
Vrms 6.38V
Vaverage 5.12V
multimeter (fluke 77) says 4.95V

Vmax 6.0v
battery 8.08v
duty cycle 63.9%
freq 700.93Hz
Vrms 6.92V
Vaverage 5.92V
multimeter (fluke 77) says 5.81V


all in all its interesting and I have really only one complaint .. I don't like 4.5v up, i rarely vape that high. but that in reality is the vmax 3.0
all it needs is a 2.0v setting as well, as it is .. it will find only very intermittent use for me.

 

Great info Stoney, would love to see Provari & LavaTube results for comparison.
I imagine though, that their rms volts are closer to what is displayed when you crank them.

 

I don't know what to make of this but have a look, you need to scroll down to post called correction by RotoHammer. #38

http://www.e-cigarette-forum.com/forum/variable-voltage-apv-discussion/320729-vmax-3rd-post-4.html

There is another one somewhere that I will link if I find it.

It is all interesting but I don't really understand the details.

RC

edit by stoney: fixed rc's link

 

So it's actually a 4.5 to 7 variable volt mod then, no wonder people reckon it hit's hard.

I guess the guy that programmed it skipped a few days from his maths and electronics course.

Wonder how well the programming in the flight controls of their new F22 Raptor knock-offs are?

 

provari is spot on, within a few mV, lava tube is fine till you meet the current or power limit, then it just doesn't tell you.

they are both DC mods, no need for rms, its the same anyway though.

 

I imagine though, that their rms volts are closer to what is displayed when you crank them.



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The gap does narrow as you increase the voltage, which would be expected.