Important Information: Reviewers and Pulse Width Modulation mods

[Rader2146]

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.

Vpeak = 6v
Duty = 50%
Freq = 1000Hz

Pre-Filter (green trace) Vrms = 4.24Vrms
Post Filter (blue trace) = ~3.0v, 61mV Ripple

 

[Stonemull]

fair enough, I'll stand corrected on that .. didn't think about that one enough. you lose all the peak voltage by the time it gets to the load.
that being said .. you are using an inductor about half the size of a house brick and we are talking about ecigs. even the cap is pretty chunky, half a carto ..

you said you could make this LC filter for $2 from memory .. needs some redesign.

 

[donnah]

I've been concerned about this since the vmax came out and the owners were claiming it was a "monster" and gave a "beastly" vape. If I set a device to a certain voltage, I want it to vape at that voltage.. no more, no less. devices with wheels (no led readout) don't really apply to this situation because they are adjusted by taste.. who knows where it's actually "set" because there is no readout to tell you, you slap a voltmeter on it and that's the voltage. (nothing against "wheel set" devices, I own 3 and enjoy them)

I don't think that the inaccurate voltage is the whole reason for the burnt boges, there's too many people experiencing this with accurate voltage devices for this to be the problem...BUT I predicted there would be a lot of burnt cartos/attys with these inaccurate devices because people set the voltage and get a much higher voltage than what they intended. I don't own one of these "beastly" devices but if I did, since I know that the voltage is different, I would know to compensate. After all, it's just numbers, kinda like knowing that there is a difference between the gallon/mile and the metric system. This info needed to be out there! Thanks for posting!

 

[6pointprime]

I've been using the meter that SF is talking about for the past few weeks. It's pretty phenomenal. In addition to the ability to measure vRMS, it can also display voltage under load, resistance under load, current under load...tons of stuff, pretty much any metric you would ever want for vaping.

The VP Live VapeTeam will be doing a segment on the VapeBrain ECD Meter this Wednesday, September 19th at 9:30 PM EST.

Here it is measuring wattage.

This is a closer front view...

And this is the back. Note the send/receive/ground contacts that can be used to connect the meter to a computer via the RS232 protocol.


Also note that it says "There once was a bear from nantucket."

 

[Sense Field]

I've been concerned about this since the vmax came out and the owners were claiming it was a "monster" and gave a "beastly" vape. If I set a device to a certain voltage, I want it to vape at that voltage.. no more, no less. Devices with wheels (no led readout) don't really apply to this situation because they are adjusted by taste.. who knows where it's actually "set" because there is no readout to tell you, you slap a voltmeter on it and that's the voltage. (nothing against "wheel set" devices, I own 3 and enjoy them)

I agree, the whole PWM devices that hit like a tank don't really hit like a tank, they are just outputting more voltage.

So really, anyone who likes them, if they were tuned correctly, that person would simply have to turn their voltage up to still get their "monster hit".

I hate to shatter the illusion that something can hit harder, but voltage is voltage

 

[Sense Field]

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

I was referring to the Zmax being expensive. Not the meter. I'm not sure if the meter will also measure non pwm device, but perhaps someone else can answer that?

 

[Stonemull]

the meter works on both pwm and non pwm mods.

linear mods like provari..
Voltage
Current
Power
Resistance

PWM mods (ego, vmax)
Peak Voltage
RMS Voltage
Peak Current
Average Power
Resistance
Duty Cycle
Frequency

 

[synthros]

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 ..

That's what I thought I was hearing, that the effective minimum voltage of say a Vmax would be closer to 4.5 volts. Yeah I would say that's a problem, unless you are strictly into high voltage vaping. Glad I didn't go with that device. That really is misleading... I wonder how much LR "software" has been wrecked as a result of this not being widely known...

 

[Rader2146]

fair enough, I'll stand corrected on that .. didn't think about that one enough. you lose all the peak voltage by the time it gets to the load.
that being said .. you are using an inductor about half the size of a house brick and we are talking about ecigs. even the cap is pretty chunky, half a carto ..

you said you could make this LC filter for $2 from memory .. needs some redesign.

Just a proof of concept. That is all.

At 1kHz (roughly the VMax's frequency) the inductor would be fairly large. The 100uF cap can be had in a 1208 package. Now on the other hand, switching converters in the 150k-600kHz range are readily available and reduce the size and values of the external components to something easily fit into a tube mod.

My main concern with "calibrating" the display to Vrms is that you are just shifting perception from one side to the other. Currently they vape stronger than what the display and a multimeter would read. After calibrating for Vrms it will vape like what the display reads, but a multimeter will read low. Since reviewers are a target audience for this thread, how are they to accurately measure the output for thier reviews?

A: Buy a True-RMS Meter.
B: Buy an oscilloscope and calculate Vrms.
C: Buy an ECD Meter.

I don't see any of these as viable options. Every one of them includes buying additional equipment. Good for the manufacturers, bad for consumers.

That's why I'm a proponent for adding a filter to produce an output that anyone with a $10 Multimeter (that no vaper worth his/her salt should be without) would be able to measure. No additional costly equipment, no math required, and what's on the screen is what you vape.

 

[Sense Field]

Just a proof of concept. That is all.

At 1kHz (roughly the VMax's frequency) the inductor would be fairly large. The 100uF cap can be had in a 1208 package. Now on the other hand, switching converters in the 150k-600kHz range are readily available and reduce the size and values of the external components to something easily fit into a tube mod.

My main concern with "calibrating" the display to Vrms is that you are just shifting perception from one side to the other. Currently they vape stronger than what the display and a multimeter would read. After calibrating for Vrms it will vape like what the display reads, but a multimeter will read low. Since reviewers are a target audience for this thread, how are they to accurately measure the output for thier reviews?

A: Buy a True-RMS Meter.
B: Buy an oscilloscope and calculate Vrms.
C: Buy an ECD Meter.

I don't see any of these as viable options. Every one of them includes buying additional equipment. Good for the manufacturers, bad for consumers.

That's why I'm a proponent for adding a filter to produce an output that anyone with a $10 Multimeter (that no vaper worth his/her salt should be without) would be able to measure. No additional costly equipment, no math required, and what's on the screen is what you vape.

They would have to buy a meter of some sorts to know what their device is actually vaping at anyway. I think they can just buy a device, know it's correct, and vape. I don't think the average vaper wants to screw around with things...they just want to know that 4v is the same vape no matter what device they choose.

 

[mostapha]

Don't buy Chinese then you will be safe. Just another reason to get a ProVari.

The provari is using ICs, which probably come from china. And my Macbook Pro deals with more power and regulates voltages better than any eCig ever will……and it was made in china.

The ICs in computers are so freaking small that a significant chunk of the power from the battery goes into replenishing electrons lost to quantum tunneling because things happen so fast and the "wires" are so small (some are ~7 atoms wide) and so tightly packed together.

And they're made in china. And they work……basically all the time.

China is not the issue.

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.

That's completely true once you have the device. But the question remains whether or not a device you're considering buying can do what you want it to do.

For a little while, I was considering getting a PWM thing as my first mod. Why? I saw a review full of numbers that I knew were completely inaccurate, but they showed the osciliscope. And it seemed like it'd give the vape I wanted to get. The review was basically worthless, and I've since learned that the scope they used has some serious flaws……but the point is that even being–ostensibly–more educated than most e-cig consumers, the review was still basically worthless for figuring out whether or not it'd work for me.

I hate to shatter the illusion that something can hit harder, but voltage is voltage

That's totally true, but there is still an issue: some of these PWM mods are firing at something ridiculous like 8 or 10V with a short duty cycle. It's not all that common, but I know I've seen Vpp (peak-to-peak voltage) numbers up there higher than anyone in their right mind would vape……and that seems like a bad idea for coil life spans if nothing else.

They would have to buy a meter of some sorts to know what their device is actually vaping at anyway. I think they can just buy a device, know it's correct, and vape. I don't think the average vaper wants to screw around with things...they just want to know that 4v is the same vape no matter what device they choose.

Here, here. Unfortunately (for many) the Provari and the Darwin are the only VV/VW devices that seem to fit the bill.

I think this "issue" probably pushed me over the edge towards a Provari. I just hope that it gets fixed in the future so that people coming in won't have to deal with all this .

 

[Butters78]

Imagine if car makers did this.. The speedometer says 45 but you are actually going 60 lol.

 

[Butters78]

Come to think of it, I hope my kick is doing what it is supposed to.

 

[Stonemull]

the kick is fine, as is every non PWM device.
easily readable on a multimeter.

 

[Butters78]

the kick is fine, as is every non PWM device.
easily readable on a multimeter.

Thanks mate I should of figured so. I'm just glad I'm in good shape with my provari and kick.

 

[Sense Field]

Here, here. Unfortunately (for many) the Provari and the Darwin are the only VV/VW devices that seem to fit the bill.

And the Darwin doesn't even seem to be made anymore.

I imagine we'll get some good devices out of china eventually. Seeing the quality of the LavaTube 2.0 and that new "Boss" mod, I'm impressed.

They just need to set the correct voltages. I have to believe they know what they are doing, the numbers just line up in that Vavg. It's got to be because we've been pushing it in reviews.

 

[mostapha]

Imagine if car makers did this.. The speedometer says 45 but you are actually going 60 lol.

They actually all do that, just the other direction. I've never driven or seen a speedometer that's completely accurate…they start out reading 1-2 mph high (you're going slower than you think you are). By the time you're at highway speeds, they're 4-7mph high. By the time you're into "losing your license" territory, they're reading 8-10mph high.

They do it as a CYA thing. No car company wants to have a speedometer that tells you you're not speeding when you are, they'd get sued. Err on the other side and no one cares.

I have to believe they know what they are doing, the numbers just line up in that Vavg. It's got to be because we've been pushing it in reviews.

You might be right, but I think it's also possible that it might be closer to the loudness war in commercial audio: if their one hits harder at the same setting than the next pv, uneducated people might think it's just "better"……if that's what they're looking for.

 

[pmos69]

If you're making a correction video, please don't call Vrms "actual voltage". It's not. A more correct description would be the "equivalent DC voltage".

The statement that "scopes" can't measure Vrms acurately is also, in general, wrong. Both digital osciloscopes and "true RMS" voltmeters generally have the capability of accurately measuring Vrms. If you have a scope that calculates Vrms incorrectly, try to get a working firmware for it.
Scopes, like "true RMS" voltmeters, calculate Vrms using it's correct definition (calculating the square root of the mean of the squares of all the sampled values), or at least they should, if they work correctly.
This enables them to calculate Vrms correctly also for waves other than perfect square waves, which are common.

 

[Sense Field]

If you're making a correction video, please don't call Vrms "actual voltage". It's not. A more correct description would be the "equivalent DC voltage".

The statement that "scopes" can't measure Vrms acurately is also, in general, wrong. Both digital osciloscopes and "true RMS" voltmeters generally have the capability of accurately measuring Vrms. If you have a scope that calculates Vrms incorrectly, try to get a working firmware for it.
Scopes, like "true RMS" voltmeters, calculate Vrms using it's correct definition (calculating the square root of the mean of the squares of all the sampled values), or at least they should, if they work correctly.
This enables them to calculate Vrms correctly also for waves other than perfect square waves, which are common.

I was speaking about the scopes that we generally use. The DSO Nano scopes.

 

[Rader2146]

They would have to buy a meter of some sorts to know what their device is actually vaping at anyway. I think they can just buy a device, know it's correct, and vape. I don't think the average vaper wants to screw around with things...they just want to know that 4v is the same vape no matter what device they choose.

I fully agree, most don't want to had to fiddle with thier device. But how are they going to know that it is accurate? Many will read/watch reviews. How will the reviewers be able to tell the audience it is accurate? Most reviewers will already have a multimeter (again, I think every vaper should have, or have access to, a multimeter just for basic troubleshooting). But a basic multimeter can't give an acurate measurement, so in order to accurately test a device, they need additional special equipment. So, as a reviewer, would you prefer to be able to accurately test a device with common equipment that you should already have, or would you rather be forced to purchase special equipment in order to accurately test a device?

Then there are the users that do like to fiddle with things. Should he have to buy special equipment to check his device? I don't feel that he should. After all, I assume that the purpose of this thread is to raise awareness of what the users what from the manufacturers. A user most likely doesn't want to pay more than he has to. So if we are proposing changes that we want to see implemented, why not ask for changes that will benefit everyone, and not just those that buy additional special equipment. As pmos put it, Vrms is "equivalent DC voltage". Why not just make it DC voltage, and then everyone is happy. If we're going to try to get this fixed, might as well get it fixed right the first time so that we don't have to do it a second time.