Important Information: Reviewers and Pulse Width Modulation mods

[Rader2146]

Stonemull, are you saying that an LC filter will not produce a low ripple DC voltage equal to the pre-filter Vavg?

If the Provari measures accurately on a multimeter, and uses PWM, how does it not vape stronger like the other "PWM" mods?

Maybe you could do a little less name calling and belittling, and actually provide some quantifying information.

 

[AttyPops]

Rader... his tone was .... kinda rough IMO given that this is not an electronics board but a board about e-cigs (and reviews).

However, I think he's trying to say "you don't need to filter it". I don't see why you would...other than to make some meter happy. The coil doesn't care if it's filtered. I'd agree with that. Measuring it and calibrating the dial is another issue.

Sorry, don't mean to .... in too much, but the PWM and/or filter isn't the point really. It's calibration for whatever voltage regulation a device uses. And of course measuring it properly for a review.

(ducks out).

 

[Stonemull]

OK. I grant you (as someone who has programmed PWM into microcontrollers) that the voltage regs in some e-cigs are not classified as PWM technically. And you're correct about the lookup table and/or calc to vary the duty cycle. However, I read here (maybe it was wrong) that the Darwin/Provari used PWM. Meh.

Bottom line is that it is a setting calibration issue. And exists on all vv e-cigs regarless of voltage regulation method. That's why I don't want to single out PWM vs other. It's really a review issue of "does this e-cig output X.X volts when set to X.X volts?". Not PWM vs buck/boost vs adjustable switching regs vs adjustable linear regs vs other.

The thing the OP was getting at is that it's hard to measure unless you have the proper equipment. And I give him credit for making the point. Also... I'm still threatening to make that color coded e-cig where you just adjust it till you like it and remember the color. No numbers to mess you up. Start at blue and move toward orange/yellow/white.

So I give credit to the OP about the issue of "How do you review it?" and continuing to raise awareness that the meters may or may not give accurate voltage readings under load. You have to know if your meter is doing a true RMS calc. Most good ones do as I understand it.

totally agree with most of this ..

provari uses PWM internally, provape say its PWM .. i think cause people have heard that pwm is more efficient than a linear regulator andvthey dumbed it down a little. I agree its being pedantic but saying the darwin and provari ARE pwm is to put them in a league with an eGo, anyone who ever looked at a scope can tell the difference between a PWM mod and a DC mod.

the only difference it might make to a user, the DC mod reads correctly on a normal multimeter the pwm one does not.

most good multimeters do NOT do rms, only the top of the line ones.
yes they measure rms on a sinusoidal wzveform, they will say mains voltage is 110v for eg. but put that AC into say a light dimmer and chop it up and the voltage reading will now be the average and incorrect, same with a pulse train .. it measures V average.

only meters that say 'true rms' will read correctly, do an ebay search for that term you will see whats applicable.

I was not disagreeing with the OP in my previous post in any way, I am here to support him with tech querys. I am the 'cole' (lol US accent) he is referring to in the video.

 

[Stonemull]

Stonemull, are you saying that an LC filter will not produce a low ripple DC voltage equal to the pre-filter Vavg?

If the Provari measures accurately on a multimeter, and uses PWM, how does it not vape stronger like the other "PWM" mods?

Maybe you could do a little less name calling and belittling, and actually provide some quantifying information.

exactly, an LC filter (assume no losses) will produce a low ripple DC voltage equal to the pre filter Vrms. Might be easier if rms was called 'true voltage' as it applys to true power. average is just that .. peak voltage has been removed and it is required for a power calculation.

I leave you with a simple question to ponder. Say you had a 300v battery, you want 3v out of it for your atty. is the correct duty cycle to use 1% ? a normal multimeter will say it is 3v. what is the power in a 2Ω atty if that pwm signal was applied ?

the provari samples its output DC and regulates the internal pwm to modify that DC .. effectively regulating to rms volts.

 

[yzer]

After the Marine Black Hawks from 29 Palms tracked me I proceeded to the the town of China Lake. I took another 30 minutes to find an involuntary safe house, where I hid for several hours. After nightfall I departed China Lake and proceeded out of town at 65 MPH along with the bulk of outgoing traffic. I was never detected, or stopped by any LE agency.

So much for 29 Palms as a security base back during the Bush administration. I would not try the same trick again, not during the Obama administration watch.

 

[Stonemull]

VF is over -----> there..

 

[silversx]

im curious to know if all vv devices have been tuned to v average then wouldn't what we set our device to be what we're used to or call a good vape?

i really want to know if my provari is tuned to vrms or vavg.. when i set my provari to 4.2 does it give me 4.2 vrms? i wish provape would come clarify or someone who has this new ECD meter or some other meter to measure vrms can test a provari..

this may not be just a china made issue.. for all we know we all have been using v average from day 1 and vrms is irrelevant.. would be helpful to see if some of our tried and true devices like the provari is tuned to vrms

 

[AttyPops]

Maybe Stonemull or others could make a mint.... just produce an "e-cig calibration tester" with a 510 connector. This would be a fairly complex box that would measure actual voltage (in a "proper" resistor? or something...not an standard atty coil resistor load) used by the manufacturers and others that REALLY wanted to shell out the bucks. Measured results at given voltage settings and calibrated to a standard.

Would avoid them having to use a meter and would be an industry standard. Or... provide a "calibration certification" facility and do it for them.

 

[Striker911]

I don't, but maybe I should. I was in wait and see mode because those things are expensive! Haha

Know if anyone selling them cheaper the $120?

So now we need two meter's? One for Pulse width and on without or will the new one do both?

 

[Stonemull]

im curious to know if all vv devices have been tuned to v average then wouldn't what we set our device to be what we're used to or call a good vape?

i really want to know if my provari is tuned to vrms or vavg.. when i set my provari to 4.2 does it give me 4.2 vrms? i wish provape would come clarify or someone who has this new ECD meter or some other meter to measure vrms can test a provari..

this may not be just a china made issue.. for all we know we all have been using v average from day 1 and vrms is irrelevant.. would be helpful to see if some of our tried and true devices like the provari is tuned to vrms

the provari is perfectly accurate.
it puts out DC which is exactly the same as rms, on DC .. the average is also the rms, so it also measures correctly on a normal meter.

this issue ONLY applys to pulsed output mods.

 

[AttyPops]

This thread is going to left field fast. Good info OP and (most) others.

Later!

 

[Stonemull]

i will answer the question i asked previously about a 300v battery ..

at 1% duty cycle the Vaverage will be 3v, if you use the average into a 2Ω atty, the power calculation (v^2)/r gives 4.5W

now .. in reality .. you are applying 300v to a 2Ω atty for 1% of the time.
when it is on .. the atty power is 45000W .. 1% of that is 450W.

so you can see an error of 10000% has crept in from using Vavg.

rms for a pulsed waveform is calculated by Vrms = Vpeak * √duty

so for the example
=300 * √0.01
= 300 * 0.1
= 30Vrms

using that in the power calculation means you get 450W for the calculation.

using rms becomes more important as the battery voltage rises.
it was never a problem with an ego but it is important to get right with dual batterys.

You can derive the error from ..
Vave = Vpeak * duty
Vrms = Vpeak * √duty

Solve for duty in both equations
duty = Vave / Vpeak
duty = (Vrms / Vpeak)²

so Vrms = Vpeak * √(Vave / Vpeak)

as Vpeak increases, Vrms increases further and further from Vavg.

 

[Stonemull]

NVM .. fixed with an edit ..

 

[AttyPops]

OK. So Vavg would be 3 and Vrms = 30. But that's for a huge Vin (300 v). Still, very well explained. Thanks!

 

[Sense Field]

the provari is perfectly accurate.
it puts out DC which is exactly the same as rms, on DC .. the average is also the rms, so it also measures correctly on a normal meter.

this issue ONLY applys to pulsed output mods.

That's exactly right. That's why you see both rms and vavg in the charts I show in the video. I was showing that the LavaTube 2.0 does eventually stop pulsing and at that point rms = vavg, at least according to what I've been told

 

[jonnypanic]

Thanks for the post. I have been doing some reading on this since I got my Young June a couple weeks ago. I knew something was up when I was using a 2.8 ohm head at 3 volts and getting good vapes. Appears that my rough estimation of adding 1 volt (when set below 4v or so) to whatever my LT was showing was close.

 

[johnnymaestro]

This thread looks like it's back on topic. Please keep it there.

 

[ByeByeCoffinNails]

I have two ego Twists and I don't look at the numbers because they are too small to read. Somehow, I manage to find the right voltage without the numbers. Is it possible for use the up/down buttons on your device to find the right temperature without worrying about numbers? Quite likely.

Charts are interesting, yes. But really, a review hinges on the build quality, battery life and ease of use.

This should not be about the country in which a mod is made. 98% of the stuff in most houses is made in China. The equipment screwed into many an "Amorrican made" Provari is made in China. The anti-Chinese sentiments are blinding people to the fact that when you ask for something to be made in China, you get what you pay for. The more you pay, the higher the quality. The Chinese could make a true Provari clone if asked- but that is not the pricepoint that is asked for is it?

This issue is a storm in a teacup and is as such, a non-event.

 

[Stonemull]

coffin nails, i can use an ego C on an ego twist, no problem at all, the twist goes down to 3.2v.
what many think this thread is about is the numbers are wrong, yes .. but it does not matter. the real problem is that a Vmax minimum setting is really 4.5v .. you cannot use a wide range of devices at, or above that voltage. who cares what the numbers say, not I, i do care that I CANNOT turn down a pv to a useable voltage.

the manufacturers have pandered to the reviewers using incorrect techniques, it is just a matter of raising awareness and it will change.

why do people say its a non issue when it can be shown that it is ?
now changing the devices to read rms IS a non issue, makes no difference to how it vapes, no difference to the electronics, just a few lines of code and the vmax can be used on a 306LR ..

 

[Sense Field]

coffin nails, i can use an ego C on an ego twist, no problem at all, the twist goes down to 3.2v.
what many think this thread is about is the numbers are wrong, yes .. but it does not matter. the real problem is that a Vmax minimum setting is really 4.5v .. you cannot use a wide range of devices at, or above that voltage. who cares what the numbers say, not I, i do care that I CANNOT turn down a pv to a useable voltage.

the manufacturers have pandered to the reviewers using incorrect techniques, it is just a matter of raising awareness and it will change.

why do people say its a non issue when it can be shown that it is ?
now changing the devices to read rms IS a non issue, makes no difference to how it vapes, no difference to the electronics, just a few lines of code and the vmax can be used on a 306LR ..

You've got it exactly right...if a person isn't worried about this...they probably vape at a high voltage, and most likely enjoy vaping at a higher voltage then they realize. In that case, it doesn't matter to them that the Vmax or any of a number of other devices don't go below 4.5v...but if someone who enjoys 4.2v or 4v picks up any of these devices...it shouldn't be too much to ask that the advertised voltage range be correct.

To explain the issue better for those who don't quite get it:
This is not about the display simply being off...this is about selling devices that have a 4.5 - 6.6 voltage range when they claim to be 3v - 6v. Pile on top of that the fact that the display is incorrect and reviews report incorrect numbers or don't seek a true explanation and you have the whole gist of this problem.