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

[khoka]

Hey everyone. I have a technical question about how APVs deal with high resistance atomizers and battery voltage drop. If I’m not mistaken, this is the equation a mod uses to calculate output voltage at the coil:

V = √R * W

So, given a coil resistance of 1 ohm and 120W of requested power, 10.95V would be required to deliver the desired wattage. But if we have 2 cells in series, that gives us 8.4V down to ~6V, which is not enough. I get told a lot that a boost converter solves this problem by increasing the output voltage, but I don’t think that’s true because it does so by stepping down the current, which leaves us with the same wattage in the end.

How does a regulated mod manage this?

 

[Don29palms]

You're correct. It can't and it doesn't.

 

[khoka]

You're correct. It can't and it doesn't.

So, does it just limit the wattage at the best it can do given the coil resistance?

 

[dwcraig1]

By drawing more amps from the battery than the board is putting out (the short answer)

 

[stratus.vaping]

Using a constant voltage/constant current regulator. A component that ( strangely enough) regulates its own output voltage/current, under the control of circuitry that allows the user to adjust the parameters of that control.

The circuit senses the voltage/current that is available from the battery, takes account of user adjusted parameters and the load, then keeps a constant output despite any reduction in available power from the battery.

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!

 

[Don29palms]

So, does it just limit the wattage at the best it can do given the coil resistance?

The battery can only put out what it has. Just because the display says something doesn't mean that's what it's putting out. If your battery can't supply the energy it can't put it out. It's like trying to go 100 miles on a gallon of gas in a Corvette.

 

[Baditude]

Buck boost circuitry



Don't ask me to try to explain it any better than that video; I'm not an electrical engineer and besides that's above my pay grade. If you can't figure it out from the video, then its all done by using tiny magical unicorns inside the regulator chip.

 

[khoka]

Buck boost circuitry



Don't ask me to try to explain it any better than that video; I'm not an electrical engineer and besides that's above my pay grade. If you can't figure it out, then its all done by using tiny magical unicorns inside the regulator.

Input power is the same as the output power. A boost converter isn’t a free energy device

 

[Don29palms]

Buck boost circuitry



Don't ask me to try to explain it any better than that video; I'm not an electrical engineer and besides that's above my pay grade. If you can't figure it out, then its all done by using tiny magical unicorns inside the regulator chip.

I understand you but you can't argue with physics. You can't put out more than you have to begin with. Maybe unicorns do exist.

 

[Baditude]

Input power is the same as the output power. A boost converter isn’t a free energy device

You can't put out more than you have to begin with.

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.

 

[Don29palms]

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

The way I explain it to myself, a boost converter takes energy from the battery and saves it, then takes more energy from the battery and saves that, and repeats those steps extremely fast until the final energy output is greater than the battery's output. It's not a free energy device, its a way to manipulate the sum output to be greater than the individual parts. The concept does have its limits, its not unlimited.

Electrical power companies do the same thing in their power stations.

Agreed. The limits are minimal. As an example. I have a Cartel Revenant regulated mod I use to check my RDAs before I put them on a mech mod. It has proven to be the most accurate mod I have. Even more accurate than my 521 tab ohm meter. It can fire a .16ohm setup at 160watts but it will not fire a .52ohm series setup at 160watts even with fully charged 25R batteries. Something has to give. Whether it's voltage or amperage. You're correct in saying I'm not an electrical engineer but for what I see in that video you should never have to replace batteries. I just use mech mods anymore so I know the batteries go dead and usually faster than I like.

 

[Baditude]

Agreed. The limits are minimal. As an example. I have a Cartel Revenant regulated mod I use to check my RDAs before I put them on a mech mod. It has proven to be the most accurate mod I have. Even more accurate than my 521 tab ohm meter. It can fire a .16ohm setup at 160watts but it will not fire a .52ohm series setup at 160watts even with fully charged 25R batteries. Something has to give. Whether it's voltage or amperage. You're correct in saying I'm not an electrical engineer but for what I see in that video you should never have to replace batteries. I just use mech mods anymore so I know the batteries go dead and usually faster than I like.

I think you're talking apples and oranges here. First you are talking about using your regulated mod to check coil resistance, another topic altogether and doesn't address the main topic of this thread. Second, regulator chipsets have closely defined limits concerning coil resistance extremes to protect the chip set.

Third, a boost converter circuit still drains batteries; its not a "battery saving" circuit.

 

[Don29palms]

I think you're talking apples and oranges here. First you are talking about using your regulated mod to check coil resistance, another topic altogether. Second, regulator chipsets have closely defined limits concerning coil resistance extremes to protect the chip set.

The point I was making is the ohms are within the limits of the mod but at .16ohms it will fire at 160 watts. At .52 ohms it will only fire at around 125 watts even though the mod is set at 160 watts. Why is that? I don't know but the mod obviously won't boost the voltage up high enough to do it.

P.S. what single battery mod will put out 7 volts? I haven't seen one yet. I'm just curious.

 

[HigherStateD]

He is also talking about how his regulated mod won fire a 0.52ohm coil at 160. Which I get. A regulated mod will pull as many amps as it can, untill the voltage dips below a predefined pound. With fresh cells, my RX2 will fire a 0.10 ohm coil at 230. Once I get below 4v per cell, it'll only fire at 207. My topside does the same thing at the low voltage point. At 3.45v, it'll only fire upto about 55w.

 

[Zaryk]

That video is much easier to understand than how they taught it in school (I did go to school in the electrical field). The idea behind it is similar to what you say, it does basically store and increase the power from the battery, then when the desired power is reached, it releases it to the coil.

It doesn't keep the battery indefinitely charged, it actually drains the battery faster using the boost circuit. It's more stressful to the battery than direct current from the battery is. This is why mechs are less stressful for a battery than a regulated mod is.

 

[Baditude]

The point I was making is the ohms are within the limits of the mod but at .16ohms it will fire at 160 watts. At .52 ohms it will only fire at around 125 watts even though the mod is set at 160 watts. Why is that? I don't know but the mod obviously won't boost the voltage up high enough to do it.

P.S. what single battery mod will put out 7 volts? I haven't seen one yet. I'm just curious.

When your mod refuses to fire at a certain wattage with a high resistance atomizer, does it display "ohms too high"? You've exceeded the preset limits of the regulation chip for that wattage setting.

A Provari was a variable voltage regulated mod which could put out up to 7 volts of power with a single 18350, 18450, or 18650 battery. It used boost circuitry, but could only fire coils between 1.2 ohm to 3.5 ohm. Not uncommon at all.

Why Provari?

 

[Don29palms]

When your mod refuses to fire at a certain wattage with a high resistance atomizer, does it display "ohms too high"? You've reached the preset limits of the regulation chip.

A Provari was a variable voltage regulated mod which could put out 7 volts of power. Not uncommon at all.

Why Provari?

Not it doesn't say ohms too high it just fires at lower watts than 160.

That's cool with the Provari. Unfortunately I've only seen pictures and never have been able to see or use one in person.

 

[Rossum]

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

I was a physics major in the 1970s and designed some serious power supplies (hundreds of kilowatts for electric furnaces) in the 1990s.

Input power is the same as the output power.

Less losses in the regulator circuit, yes.

Volts x amps out = Volts x amps in.

But if a regulator has a maximum output voltage of say, 8V, then it cannot produce 100 watts into a 1.0 ohm load. A similar situation exists at the other end. If a regulator can only supply 25 amps, then it cannot produce 100 watts into a 0.1 ohm load.

This means there is a "sweet region" of resistance values in which a particular regulator can produce full rated power. It may be willing to fire resistances well outside of that sweet region, but it won't be able to produce full rated power if the load's resistance is outside that region.

 

[RayofLight62]

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.

Some brands / models use a more sophisticated approach; i.e. a dinamic feedback instead of the "power / resistances" table of values.

Temperature controlled mods add another layer of complexity, as the wattage become dependent upon the resistance variations of the coil, which are - in turn - dependent upon temperature changes.

This is implemented with various level of competence and complexity among vape manufacturers.

 

[Rossum]

Hey everyone. I have a technical question about how APVs deal with high resistance atomizers and battery voltage drop. If I’m not mistaken, this is the equation a mod uses to calculate output voltage at the coil:

V = √R * W

So, given a coil resistance of 1 ohm and 120W of requested power, 10.95V would be required to deliver the desired wattage. But if we have 2 cells in series, that gives us 8.4V down to ~6V, which is not enough. I get told a lot that a boost converter solves this problem by increasing the output voltage, but I don’t think that’s true because it does so by stepping down the current, which leaves us with the same wattage in the end.

How does a regulated mod manage this?

If this the regulator were capable of boost operation (unlikely on a mod that uses series batteries), then it would supply 10.95 volts to the coil by pulling roughly 20A from the batteries when the 2S string is down to 6 volts.