How does a regulated mod increase battery voltage to maintain desired wattage?

[Rossum]

When you screw in the atomiser, the device read its resistance and set the voltage to a value which will deliver the SET wattage.

This is valid for the vast majority of mods.

Any mod that does VW by measuring resistance only once is joke. Yes, I'm aware that some Chinese dna clones did that ~5 years ago, but I can't really imagine them doing that today.

It's fairly straightforward to monitor both current and voltage while firing, and if you know both, then you can easily calculate resistance and power on the fly.

 

[stratus.vaping]

Several disagreed with my post, could they explain please? I'd be interested in your opinion, we are all learning here. 8)

 

[HigherStateD]

I don't see it as the chip storing power, as would be the case with PWM circuitry, but more as if it acts as a very low resistance bridge.

Several disagreed with my post, could they explain please? I'd

be iinterestedin your opinion, we are all learning here. 8)

Buck-Boost IC - Linear Technology/Analog Devices - Buck-Boost | Online Catalog | DigiKey Electronics

I don't see marketing hype, just technical specs.

 

[Dougiestyle]

Flux capacitors. And tiny little chinese whizzerydooz(sp?) Also whingamajingz (sp?) Can create a fusion of electrons to increase the amount of supplied voltage by converting amps to voltage. Circuit limits and battery discharge ratings being the bottleneck.

 

[stratus.vaping]

I don't see it as the chip storing power, as would be the case with PWM circuitry, but more as if it acts as a very low resistance bridge.

Buck-Boost IC - Linear Technology/Analog Devices - Buck-Boost | Online Catalog | DigiKey Electronics

I don't see marketing hype, just technical specs.

A chip does not store that kind of energy in that kind of circuit, a capacitor/s does as it is pulsed in by the MOSFET circuit, then released. Agreed Buck-Boost etc does exist ofc, I mentioned it. But imho it has been seized on by marketing in the vape world and has been hyped up, as such things often are.

Thanks for your reply.

 

[HigherStateD]

A chip does not store that kind of energy in that kind of circuit, a capacitor/s does as it is pulsed in by the MOSFET circuit, then released. Agreed Buck-Boost etc does exist ofc, I mentioned it. But imho it has been seized on by marketing in the vape world and has been hyped up, as such things often are.

Thanks for your reply.

Agreed there. People think just because an aegis solo says it can hit 100w on an 18650, that they can go down to radio shack and buy an untrafire and rock out... It'll do it, but not for long.

 

[Baditude]

I would imagine that the term "boost converter" is a hype by vape manufacturers because as you say, voltage is maintained at the expense of current. Basically they are a kind of switch mode power supply (usually called a DC-DC convertor) that uses a pulsing MOSFET switch circuit , it "steps up" the source voltage, but as P=VI rules supreme the output current reduces.

Marketing bullshyt!

Several disagreed with my post, could they explain please? I'd be interested in your opinion, we are all learning here. 8)

It's not marketing bullshyt.

Evidence that variable voltage and "boost circuitry" works: PBusardo tests the Provari on an oscelloscope up to a 7 volt setting and guess what, it puts out 7 volts output on a 4.2 volt single battery as advertized. Oscelloscope tests results begin at the 27 minute mark if you wish to skip to that part of the video.



To be honest, I don't know if the technical term is called boost circuitry, pulse width modulation, or magic, but it works.

 

[stratus.vaping]

It's not marketing bullshyt.

Proof that variable voltage and boost circuitry works. PBusardo tests the Provari on an oscelloscope up to a 7 volt setting and guess what, it puts out 7 volts output on a 4.2 volt single battery. Oscelloscope tests results begin at the 27 minute mark if you wish to skip to that part of the video.



To be honest, I don't know if its call boost circuitry, pulse width modulation, or magic, but it works.

I wasn't clear enough as usual, sorry.

I did not say that those principles didn't work. In a later post I explained a little of the basics of how it works, it's further back somewhere you may have missed it.

I stated in my first post that it is a real circuit and that it works, it's used in many industries and devices. I went on to say that increasing voltage is at the expense of current, so it's swings and roundabouts. Battery life is reduced too as others pointed out. There is no such thing as a free lunch in electronics, if there were we would have perpetual motion and free energy... so you cannot get a few extra volts and not lose something else somewhere.

I have built high current power supplies, voltage regulators and so on over the years and use them daily in my hobbies. I'm not an electronics pro, my maths is awful, but I am familiar with most working principles.

I did say that vape marketing hypes it, same as they do with "protections", imho ofc.

Thanks for replying, hope that clears it up. I must be less vague!

 

[Rossum]

I did say that vape marketing hypes it, same as they do with "protections", imho ofc.

Some manufacturers engage in hype, sure. They sell dual 18650 mods that they rate at 200 watts or more.

A regulator is either going to be designed to boost, buck, or both. Using a single sell (or even several cells in parallel) you really want both in order to support a wide range of resistances. With two cells in series, buck works pretty well, but having both does widen the range of resistances you can make full power into. With three cells in series, boost becomes superfluous.

 

[GOMuniEsq]

As I said above, I'm not an electrical engineer or physics major; are you?

The way I explain it to myself, a boost converter takes a pulse of energy from the battery and saves it, then takes another pulse of energy from the battery and saves that, and repeats those steps extremely fast (hundreds of times per second) until the saved energy is greater than the battery's output.

It's not a free energy device, its a way to manipulate the sum electrical output to be greater than the individual single pulses from the battery. The concept does have its limits, its not unlimited.

This is how variable voltage regulated devices could put out up to 7 volts of power from a single 4.2 volt battery. Electrical power companies do the same thing in their power stations.

If you can't understand that, then yes, its unicorns.

I spent an embarrassing amount of time trying to concoct an analogy without success. Best I can was this: though a town may not be able to afford a single enormous pump that can supply thousands of homes with high pressure water, it can use a smaller pump to fill a water tower that accomplishes the same thing. Pressure being the analogy for voltage. Thousands of times per second thanks to unicorns.

 

[HigherStateD]

I spent an embarrassing amount of time trying to concoct an analogy without success. Best I can was this: though a town may not be able to afford a single enormous pump that can supply thousands of homes with high pressure water, it can use a smaller pump to fill a water tower that accomplishes the same thing. Pressure being the analogy for voltage. Thousands of times per second thanks to unicorns.

I see it more like magical unicorns, taunting entropy, with optimistic towns people, building right below hover dam, wondering why it's not safe to demand a waterslide system...

 

[Punk In Drublic]

It's not marketing bullshyt.

Evidence that variable voltage and "boost circuitry" works: PBusardo tests the Provari on an oscelloscope up to a 7 volt setting and guess what, it puts out 7 volts output on a 4.2 volt single battery as advertized. Oscelloscope tests results begin at the 27 minute mark if you wish to skip to that part of the video.



To be honest, I don't know if the technical term is called boost circuitry, pulse width modulation, or magic, but it works.

Perhaps in another video PBusardo displays the screen grabs taken from his oscilloscope – but not this one. This just displays a simple graph. Non the less, despite the Provari is able to boost voltage to 6 volts (through the use of inductors), it suffers from a ~3.5 amp current limitation and fails to fire lower resistance coils (not subohm) at higher voltages. Technically, this is not much different than our modern devices failing to reach maximum wattage with higher resistance coils due to their voltage limitations.

People tend to focus on the max wattage and neglect the max voltage or max current the device is able to deliver – assuming of course such specs are given (not all manufactures give these specs).

DNA75C - 75 watts max, but with a max output voltage of 9 volts (according to spec) and a 30 amp continuous max current output. Max input voltage is 4.2 volts (single cell). 9 volt output is pretty impressive for a single cell device, but no matter how you cut it, you will not be hitting 75 watts with a 1.1+ ohm coil given the devices limitations.

DNA250C – 200 to 400 watts depending on cell config, but with a max output voltage of only 10 volts, even with a 4 cell device. If you have a 200 watt device, 0.5 ohms or greater will not be able to hit that 200 watt mark, a 300 watt device, 0.33 ohms or greater, and a 400 watt device, 0.25 ohms or greater.

Evolve demonstrates this with the power graphs within their board’s data sheets.

 

[stratus.vaping]

I'm off to order more Unicorns from Radio Spares, cul.

 

[mcclintock]

The simplest electrical analogy is a transformer and the mechanical analogy is a gear box. A gear box can boost RPM at the cost of output torque or boost torque or hill-climbing ability at the cost of reducing RPM/speed capability or in the case of an engine requiring more RPM into it to maintain speed.

One single cell mod that can put out 8.4V I think it was is an iStick 30 from 5 years ago or something. I ran it at 7.4V, 22W into 2.4 ohms for a while, actually the highest power I've ever used more than a half hour. The coil was twisted 32 gauge which of course uses 4 times the wire, twice the wraps and 4 times the power of a single wire coil using that gauge and resistance. Later I also tried #26 Kanthal at .6 ohms 11 watts 2.6V (1/16" I.D.) and actually the mod ran hotter.

 

[RayofLight62]

Both boost and buck converters do change the DC input voltage. Store the energy into a coil first, then release into the load.

The V x I relationship between input and output stays constant, minus the conversion losses, around 3 to 8% of the converted power.

The energy that the coil can store is defined as E = 1/2 L x I ^2, where L is the inductance (in Henry) of the coil.

The output regulation is achieved by varying the amount of time the coil is allowed to charge. The waveform is then rectified and fed to the atomiser.

By using an additional MOSFET transistor instead of a standard Schotty diode, and driving it with the same clock signal of the main switcher transistor, it does make a syncronous rectifier, which has no power losses due to the diode bandgap voltage, so allowing the converter to be highly efficient and precise.

A PWM circuit is an hystoric circuit configuration, used for power regulation when high flux ferrites and high power switching transistors didn't exist. Basically, a PWM circuit turns power on/off across the load to allow some degree of regulation.

PWM was used to control incandescent lamps, model train motors, and by some cheap automotive LED lighting. It didn't require coils, diode or capacitors, so it was very cheap to make.

It was phased out of flashlight use because it can induce Troxler's fading into user's sight, leading to dangerous situations in the dark.

Mods using PWM fall out of use some time ago; I still have the original iStick 20W - the rattlesnake mod.
But since there were some request nonetheless, I think there are some PWM mods available now on the market.

 

[Baditude]

I spent an embarrassing amount of time trying to concoct an analogy without success. Best I can was this: though a town may not be able to afford a single enormous pump that can supply thousands of homes with high pressure water, it can use a smaller pump to fill a water tower that accomplishes the same thing. Pressure being the analogy for voltage. Thousands of times per second thanks to unicorns.

Ironic. While trying to explain Ohm's Law, I used a water wheel as an anology. No unicorns were harmed in the making of this presentation.

Ohm's Law Explained for Vapers

 

[AttyPops]

The V x I relationship between input and output stays constant, minus the conversion losses, around 3 to 8% of the converted power.

This. Basically watts out = watts in (resistance doesn't change much for purposes of discussion, disregarding losses too)

So pump up the voltage-out, and you output less amps than you drew. You exchange amps for higher volts.

Or like the gearbox analogy above.

And like most everyone is saying, the device can be amp-limited by the battery.

 

[Punk In Drublic]

I know we jest with the unicorn comments but we have to understand we are dealing with specific limitations in order to keep a vape device marketable in terms of cost, size, functionality and efficiency. That is not to say there are poor designs out there, but many employ a design limitation for a reason. You can take an input voltage range of 6.4 to 8.4 volts (dual series mod), and generate ~24.5 volts through a boost converter that is needed to run a 3 ohm coil at 200 watts, but what components are required to perform such a task and will the final product still be marketable in terms of size and cost?

I would like to draw a correlation with audio power amplifiers. In order to achieve a linear output, an audio amplifier should double its power output with each half of speaker impedance. So a 50 watt amplifier into 8 ohms should output 100 watts into 4 ohms and 200 watts into 2 ohms. Many consumer, even professional amplifiers are unable to achieve this, some struggle with a 4 ohm load and many just give up the ghost with a 2 ohm load. Why is this when speaker impedances fluctuate across their audio band? It is not because this design objective is unobtainable, but because the designer made a choice to sacrifice a linear output for say cost, efficiency or even form factor (size). One can purchase amplifiers that double their power output for every half of speaker impedance (even with both channels driven), and are stable down to a 2 ohm load - but many of these amplifiers cost the same as an average car and require a team of professional wrestlers to carry the behemoth into your listening room. It’s all relative of design, and if you want something small and inexpensive, you are limited with what speaker you can use with it.

Keith Bontrager, a key figure in the bicycle industry, came up with this quote in terms of bicycle design – Strong, Light, Cheap…you can only pick 2 when designing a bicycle. This analogy, although by changing the wording to a degree, can be applied to many industries.

 

[Baditude]

... many of these amplifiers cost the same as an average car and require a team of professional wrestlers to carry the behemoth into your listening room.

This anology reminds me of those massive Klipschhorn audio loudspeakers that I used to drool over at the high end audio store. The salesman would lightly tap the ends of the speaker wires with a 9 volt battery and you'd hear and feel such a loud THUMP! from the speakers that the sonic wave would move your hair.

 

[Baditude]

A chip does not store that kind of energy in that kind of circuit, a capacitor/s does as it is pulsed in by the MOSFET circuit, then released. Agreed Buck-Boost etc does exist ofc, I mentioned it. But imho it has been seized on by marketing in the vape world and has been hyped up, as such things often are.

Thanks for your reply.

So, what is the alternative to adjust power output on the fly?