This entry started as a reply to user Vapenstein apropos of his hcigar DNA40 mod which was behaving funny about the battery status. It was then converted into several replies, here and there, even in Spanish forums, as the equations are of fully universal application.... and the questions about currents in the atomizer and battery for VW mods are constantly arising...
But as time goes by, the original intentions are meaningless and add an unrequited length to the text, so I'll cut it down. At the end you might find the original post, if you're curious enough.
The thing about VV/VW and their electronics control module is that they effectively separate atomizers and batteries. It's like it appeared a voltage transformer between both parts (and in many senses it is). They call it DC-DC converter, and their maths are relatively simple. All the energy (or energy per time unit, i. e. power) drawn from the battery is converted in the same energy (power) applied to the atomizer, it just interchanges voltages and currents. But remembering that P = V * I it's a simple math.....
Yes, that's the same in a simple AC-AC transformer, but the AC keyword is important. You can change voltages and currents between copper coils linked by magnetic conductors (and that's precisely an AC transformer), but it happens just because the current is alternate current.
With DC currents, that one from our batteries, an AC transformer does not work. But with electronics you can transform DC current into AC, change it, and finally filter it to a new DC current with different voltage (and current). In its modern form, it is called switched converter, uses a high frequency DC-AC-DC modulator to improve yields and it has colonized all our electronics. And the core of a VW mod is just another one of these, with voltages controlled by a microprocessor which takes the user input (the wattage desired or the temperature desired, in the TC controlled mods).
There is some urban myths apparently based on user's experiences. Early VW were of low power output and do not show the great current draws that we now see in modern VW's. And the first really successful high power output VW circuits all have a common flaw: they lack of the possibility of reducing voltages below battery output, the famous 'step-down' capability. Like DNA30D and its many clone siblings, they cannot go below 3,6 V, at last.
So, you put a sub-ohm atomizer in those, set it to 7W of output....and apparently it depletes the battery too soon! Well, for starters, some VW were not designed to sub-ohm atomizers, which by the way are a necessity for mechanical mods, but not for VW. But more importantly, they cannot provide just '7W' if the atomizer resistance falls below 1,8 Ω! So now it naturally appears the real battery-eater: in sub-ohm setups your DNA30 (and related ones) goes at a minimum of 13 W, regardless what the screen says !
Returning to our converters and how they act, to all intents and purposes, batteries and atomizers are now absolutely separated. The voltages and currents in each side are not the same. They are linked by energy considerations, as the energy per time unit, i.e., power measured in watts, travels through the assembly of electronic circuits, gets changed, and does its work in our coils. But it is not true that a low resistance coil in your atomizer will deplete your battery quicker, as it drains more current from it. Not unless you also set a high wattage output, or you run your mod dangerously near its boundaries for resistances, which, if it has been properly designed and manufactured, it should refrain to do so.
Well, there are some energy losses inside the converter, a yield (or efficiency) factor involved, which usually falls in the 0,90 through 0,96 (or 90% up to 96%), which means that the energy drawn from the battery is partially lost (the difference between 100 and the yield in %) as heat in the innards of the converter. It's an unavoidable toll to get constant power through the decay of the batteries and to make possible the DC conversion.
Having said all that, your applied current through the atomizer, even in the case of very low resistance (nickel and temperature control active), doesn't matter much. It's about power applied, and then requested to the battery, plus the losses. The batteries always works at its natural voltage output (4,2 fully charged, and so on), so it doesn't matter (at first approach) how the electronics feed the atomizers, it does count how much power the electronics pull from the battery, and from that power, the current is fixed by the P = V * I formula, as V is a fixed parameter.
On second approach, yields do change over the current and power applied over the atomizer, but its changing is not so big if you work between boundaries of the electronics, and usually the electronics are controlled by some logics to cut output outside the boundaries, hence the low resistance, check atomizer, high load, etc., messages.
Let's take an example: If I vape at 39w with a 0.5 Ω coil, I am running just under 9A.
Well, in the atomizer side, maybe, but in the battery side, no, you don't!
39 W of power plus the losses are drawn from the batteries, now the resistance does not count, we have the power! The 'at X Ω' does not add more relevant info . Let's say for the sake of this example they are about 50 %, that is, at 3,7 V of output voltage. In the side of the atomizer (with 0,5 Ω coil) you are effectively putting about 8,8 A, but in the side of the batteries, with a typical 93% of yield, you are pulling out 42 W, and at 3,7 V that means 11 A. The atomizer resistance (being that with nickel or with any other material) does not count for these calculations, it only appears in the atomizer side once you need to know the current applied, but with very different resistances (like kanthal and nickel ones), provided they are inside the electronic boundaries, the power and battery drain are essentially the same.
Just to end this hefty volume (someone should cut my fingers!....
), the equations involved, a derivative of the well known ones from Ohm's law:
where η is the greek letter 'eta', usually used for this yield/efficiency matters in engineering and physics.... According to Evolv's statements, DNA40 is rated at 93%.
*** This was the original post for this blog***
The thing about VV/VW and their electronics control module is that they effectively separate atomizers and batteries. It's like it appeared a voltage transformer between both parts (and in many senses it is). They call it DC-DC converter, and their maths are relatively simple. All the energy (or energy per time unit, i. e. power) drawn from the battery is converted in the same energy (power) applied to the atomizer, it just interchanges voltages and currents. but remembering that P = V * I it's a simple math.....
Well, there are some energy losses inside the converter, a yield (or efficiency) factor involved, which usually falls in the 0,90 through 0,96 (or 90% up to 96%), which means that the energy drawn from the battery is partially lost (the difference between 100 and the yield in %) as heat in the innards of the converter. It's an unavoidable toll to get constant power through the decay of the batteries.
Having said all that, your applied current through the atomizer, even in the case of very low resistance (nickel and temperature control active), doesn't matter much. It's about power applied, and then requested to the battery, plus the losses. The batteries always works at its natural voltage output (4,2 fully charged, and so on), so it doesn't matter (at first approach) how the electronics feed the atomizers, it does count how much power the electronics pull from the battery, and from that power, the current is fixed by the P = V * I formula, as V is a fixed parameter.
On second approach, yields do change over the current and power applied over the atomizer, but its changing is not so big if you work between boundaries of the electronics, and usually the electronics are controlled by some logics to cut output outside the boundaries, hence the low resistance, check atomizer, high load, etc., messages.
Some people have said that as the electronics cut off partially power once the temperature of the coil pass over the setting point, in this mode the power consumption (i.e. draw from the batteries) is even lower. But that supposes you're running your atomizer dangerously near the dry-hit without temperature control. My opinion is that temperature control is a big step forward, but it cannot improve our taste buds, and surely it wasn’t their intention: they are far better detectors of the 'dry-hit' situation......
About your example:
39 W of power plus the losses are drawn from the batteries, now the resistance does not count, we have the power! The 'at X Ω' does not add more relevant info . Let's say for the sake of this example they are about 50 %, that is, at 3,7 V of output voltage. In the side of the atomizer (with 0,5 Ω coil) you are effectively putting about 8,8 A, but in the side of the batteries, with a typical 93% of yield, you are pulling out 42 W, and at 3,7 V that means 11 A. The atomizer resistance (being that with nickel or with any other material) does not count for these calculations, it only appears in the atomizer side once you need to know the current applied, but with very different resistances (like kanthal and nickel ones), provided they are inside the electronic boundaries, the power and battery drain are essentially the same.
Now about the 'weak battery' message. DC-DC converters monitor the voltage output of batteries so they can warn us about their state (cut off near depletion). They do that in two ways: monitoring voltage output without load (it should be over 3,2 - 3,4 V) and monitoring the voltage drop when batteries are under load. If the voltage drop is bigger than some specified parameter the converter interprets this as a low battery or a weak battery, if the voltage without load appears normal.
But in your HCig mods, or at least some of them, the battery is not properly connected to the board. Under heavy loads (near the 40 W upper limit) the improper connection adds some voltage drop to the battery under load, and the converter takes that as a weak battery, but instead is a weak connection. Same happens with the improper battery, one that cannot pull out enough current due to its internal resistance or state. Improve the connection (taking out the anodized, putting additional wiring) and the problem will be fixed.
Just to end this hefty volume (someone should cut my fingers!....), the equations involved, a derivative of the well known ones from Ohm's law:
where η is the greek letter 'eta', usually used for this yield/efficiency matters in engineering and physics.... According to Evolv's statements, DNA40 is rated at 93%.
But as time goes by, the original intentions are meaningless and add an unrequited length to the text, so I'll cut it down. At the end you might find the original post, if you're curious enough.
The thing about VV/VW and their electronics control module is that they effectively separate atomizers and batteries. It's like it appeared a voltage transformer between both parts (and in many senses it is). They call it DC-DC converter, and their maths are relatively simple. All the energy (or energy per time unit, i. e. power) drawn from the battery is converted in the same energy (power) applied to the atomizer, it just interchanges voltages and currents. But remembering that P = V * I it's a simple math.....
Yes, that's the same in a simple AC-AC transformer, but the AC keyword is important. You can change voltages and currents between copper coils linked by magnetic conductors (and that's precisely an AC transformer), but it happens just because the current is alternate current.
With DC currents, that one from our batteries, an AC transformer does not work. But with electronics you can transform DC current into AC, change it, and finally filter it to a new DC current with different voltage (and current). In its modern form, it is called switched converter, uses a high frequency DC-AC-DC modulator to improve yields and it has colonized all our electronics. And the core of a VW mod is just another one of these, with voltages controlled by a microprocessor which takes the user input (the wattage desired or the temperature desired, in the TC controlled mods).
There is some urban myths apparently based on user's experiences. Early VW were of low power output and do not show the great current draws that we now see in modern VW's. And the first really successful high power output VW circuits all have a common flaw: they lack of the possibility of reducing voltages below battery output, the famous 'step-down' capability. Like DNA30D and its many clone siblings, they cannot go below 3,6 V, at last.
So, you put a sub-ohm atomizer in those, set it to 7W of output....and apparently it depletes the battery too soon! Well, for starters, some VW were not designed to sub-ohm atomizers, which by the way are a necessity for mechanical mods, but not for VW. But more importantly, they cannot provide just '7W' if the atomizer resistance falls below 1,8 Ω! So now it naturally appears the real battery-eater: in sub-ohm setups your DNA30 (and related ones) goes at a minimum of 13 W, regardless what the screen says !
Returning to our converters and how they act, to all intents and purposes, batteries and atomizers are now absolutely separated. The voltages and currents in each side are not the same. They are linked by energy considerations, as the energy per time unit, i.e., power measured in watts, travels through the assembly of electronic circuits, gets changed, and does its work in our coils. But it is not true that a low resistance coil in your atomizer will deplete your battery quicker, as it drains more current from it. Not unless you also set a high wattage output, or you run your mod dangerously near its boundaries for resistances, which, if it has been properly designed and manufactured, it should refrain to do so.
Well, there are some energy losses inside the converter, a yield (or efficiency) factor involved, which usually falls in the 0,90 through 0,96 (or 90% up to 96%), which means that the energy drawn from the battery is partially lost (the difference between 100 and the yield in %) as heat in the innards of the converter. It's an unavoidable toll to get constant power through the decay of the batteries and to make possible the DC conversion.
Having said all that, your applied current through the atomizer, even in the case of very low resistance (nickel and temperature control active), doesn't matter much. It's about power applied, and then requested to the battery, plus the losses. The batteries always works at its natural voltage output (4,2 fully charged, and so on), so it doesn't matter (at first approach) how the electronics feed the atomizers, it does count how much power the electronics pull from the battery, and from that power, the current is fixed by the P = V * I formula, as V is a fixed parameter.
On second approach, yields do change over the current and power applied over the atomizer, but its changing is not so big if you work between boundaries of the electronics, and usually the electronics are controlled by some logics to cut output outside the boundaries, hence the low resistance, check atomizer, high load, etc., messages.
Let's take an example: If I vape at 39w with a 0.5 Ω coil, I am running just under 9A.
Well, in the atomizer side, maybe, but in the battery side, no, you don't!
39 W of power plus the losses are drawn from the batteries, now the resistance does not count, we have the power! The 'at X Ω' does not add more relevant info . Let's say for the sake of this example they are about 50 %, that is, at 3,7 V of output voltage. In the side of the atomizer (with 0,5 Ω coil) you are effectively putting about 8,8 A, but in the side of the batteries, with a typical 93% of yield, you are pulling out 42 W, and at 3,7 V that means 11 A. The atomizer resistance (being that with nickel or with any other material) does not count for these calculations, it only appears in the atomizer side once you need to know the current applied, but with very different resistances (like kanthal and nickel ones), provided they are inside the electronic boundaries, the power and battery drain are essentially the same.
Just to end this hefty volume (someone should cut my fingers!....
), the equations involved, a derivative of the well known ones from Ohm's law:
where η is the greek letter 'eta', usually used for this yield/efficiency matters in engineering and physics.... According to Evolv's statements, DNA40 is rated at 93%.
*** This was the original post for this blog***
Vapenstein;15318007 said:
The thing about VV/VW and their electronics control module is that they effectively separate atomizers and batteries. It's like it appeared a voltage transformer between both parts (and in many senses it is). They call it DC-DC converter, and their maths are relatively simple. All the energy (or energy per time unit, i. e. power) drawn from the battery is converted in the same energy (power) applied to the atomizer, it just interchanges voltages and currents. but remembering that P = V * I it's a simple math.....
Well, there are some energy losses inside the converter, a yield (or efficiency) factor involved, which usually falls in the 0,90 through 0,96 (or 90% up to 96%), which means that the energy drawn from the battery is partially lost (the difference between 100 and the yield in %) as heat in the innards of the converter. It's an unavoidable toll to get constant power through the decay of the batteries.
Having said all that, your applied current through the atomizer, even in the case of very low resistance (nickel and temperature control active), doesn't matter much. It's about power applied, and then requested to the battery, plus the losses. The batteries always works at its natural voltage output (4,2 fully charged, and so on), so it doesn't matter (at first approach) how the electronics feed the atomizers, it does count how much power the electronics pull from the battery, and from that power, the current is fixed by the P = V * I formula, as V is a fixed parameter.
On second approach, yields do change over the current and power applied over the atomizer, but its changing is not so big if you work between boundaries of the electronics, and usually the electronics are controlled by some logics to cut output outside the boundaries, hence the low resistance, check atomizer, high load, etc., messages.
Some people have said that as the electronics cut off partially power once the temperature of the coil pass over the setting point, in this mode the power consumption (i.e. draw from the batteries) is even lower. But that supposes you're running your atomizer dangerously near the dry-hit without temperature control. My opinion is that temperature control is a big step forward, but it cannot improve our taste buds, and surely it wasn’t their intention: they are far better detectors of the 'dry-hit' situation......
About your example:
Vapenstein;15318007 said:
39 W of power plus the losses are drawn from the batteries, now the resistance does not count, we have the power! The 'at X Ω' does not add more relevant info . Let's say for the sake of this example they are about 50 %, that is, at 3,7 V of output voltage. In the side of the atomizer (with 0,5 Ω coil) you are effectively putting about 8,8 A, but in the side of the batteries, with a typical 93% of yield, you are pulling out 42 W, and at 3,7 V that means 11 A. The atomizer resistance (being that with nickel or with any other material) does not count for these calculations, it only appears in the atomizer side once you need to know the current applied, but with very different resistances (like kanthal and nickel ones), provided they are inside the electronic boundaries, the power and battery drain are essentially the same.
Now about the 'weak battery' message. DC-DC converters monitor the voltage output of batteries so they can warn us about their state (cut off near depletion). They do that in two ways: monitoring voltage output without load (it should be over 3,2 - 3,4 V) and monitoring the voltage drop when batteries are under load. If the voltage drop is bigger than some specified parameter the converter interprets this as a low battery or a weak battery, if the voltage without load appears normal.
But in your HCig mods, or at least some of them, the battery is not properly connected to the board. Under heavy loads (near the 40 W upper limit) the improper connection adds some voltage drop to the battery under load, and the converter takes that as a weak battery, but instead is a weak connection. Same happens with the improper battery, one that cannot pull out enough current due to its internal resistance or state. Improve the connection (taking out the anodized, putting additional wiring) and the problem will be fixed.
Just to end this hefty volume (someone should cut my fingers!....
), the equations involved, a derivative of the well known ones from Ohm's law:
where η is the greek letter 'eta', usually used for this yield/efficiency matters in engineering and physics.... According to Evolv's statements, DNA40 is rated at 93%.
