voltage question

[mokeife]

maybe a bad batch of batteries?

i dont think so as it always sags that much and i have like 10 different batteries all bought at different times

 

[mokeife]

i have a multimeter whats the correct way to measure it?

 

[mokeife]

if i put the multimeter on the battery contact and fire it it drops from 4.1 to 3.7

 

[mokeife]

the other battery drops from 4.1-3.8

 

[fq06]

they shouldn't be dropping. Even at 60 amps they don't sag. not until 70 amps do they sag that much

That graph shows a sag from just about 4.2v down to about 3.3v at a 40a load. And that's a battery testing setup with just about zero voltage drop. 1v to maybe 1.3v should be expected from a mod if you are going by that test.

70a test dropped below the testing range, totally unsafe. Doesn't look like he even did the 70a test for more than one pulse and called it quits before he set his garage on fire lol.

 

[mokeife]

That graph shows a sag from just about 4.2v down to about 3.3v at a 40a load. And that's a battery testing setup with just about zero voltage drop. 1v to maybe 1.3v should be expected from a mod if you are going by that test.

70a test dropped below the testing range, totally unsafe. Doesn't look like he even did the 70a test for more than one pulse and called it quits before he set his garage on fire lol.

thats about what i get .95-1 volt and i really dont think my batteries are fakes they were all bought from reputable dealers

 

[SirRichardRear]

That graph shows a sag from just about 4.2v down to about 3.3v at a 40a load. And that's a battery testing setup with just about zero voltage drop. 1v to maybe 1.3v should be expected from a mod if you are going by that test.

70a test dropped below the testing range, totally unsafe. Doesn't look like he even did the 70a test for more than one pulse and called it quits before he set his garage on fire lol.

u know what I was reading the chart wrong, i was looking at it backwards lol
anyway he is pushing 22 amps so the lowest measured on the chart is 30 amps. and even at that it sags down to about 3.45 form 4.1 so a .65 Sag

 

[fq06]

That is normal, most people don't pay attention to the live voltage bar on their regulated mods because it's on the side and you cant see it when you take a pull. If you were to look at it the bar will usually drop 30% to 50% depending on the build and wattage it's set at.
Yours is just whatever the build is but in a mod you can change wattage there is a big difference in bar change from 10w to 100w. 10w barely moves the bar.

 

[fq06]

u know what I was reading the chart wrong, i was looking at it backwards lol
anyway he is pushing 22 amps so the lowest measured on the chart is 30 amps. and even at that it sags down to about 3.45 form 4.1 so a .65 Sag

Hard to say what he is pushing, a big fat fused clapton or dragon coil or whatever shit people are running draws a lot of power.
So a basic round wire build @ 0.3 is different from an alien 0.3 build.

That is also a testing setup so it is about as efficient as it gets. That does not relate 1:1 to what you actually see from a mod.

 

[mokeife]

u know what I was reading the chart wrong, i was looking at it backwards lol
anyway he is pushing 22 amps so the lowest measured on the chart is 30 amps. and even at that it sags down to about 3.45 form 4.1 so a .65 Sag

you scared me lol

 

[fq06]

Also, if you look, it starts higher than 4.1v. Those are fresh off the charger cells.
Every pulse after the first starts a little lower from power being taken out and starting at a new lower resting voltage.

 

[SirRichardRear]

Hard to say what he is pushing, a big fat fused clapton or dragon coil or whatever shit people are running draws a lot of power.
So a basic round wire build @ 0.3 is different from an alien 0.3 build.

That is also a testing setup so it is about as efficient as it gets. That does not relate 1:1 to what you actually see from a mod.

Ohms law is ohms law. it's 22 amps regardless of what kind of coils are used. The difference is claptons will need more amps to ramp up then less wires. but that doesn't change ohms law

 

[SirRichardRear]

That is normal, most people don't pay attention to the live voltage bar on their regulated mods because it's on the side and you cant see it when you take a pull. If you were to look at it the bar will usually drop 30% to 50% depending on the build and wattage it's set at.
Yours is just whatever the build is but in a mod you can change wattage there is a big difference in bar change from 10w to 100w. 10w barely moves the bar.

to test this, using my G2 my weak batteries (27% left) dropped from my setting of 4.5v to 3.6 but putting in a fresh set of fully charged batteries, my voltage didn't drop at all

 

[fq06]

Ohms law is ohms law. it's 22 amps regardless of what kind of coils are used. The difference is claptons will need more amps to ramp up then less wires. but that doesn't change ohms law

Your right, I'm so used to a regulated mod and adjusting watts higher than normal when running a gucci coil instead of a regular round wire coil.

to test this, using my G2 my weak batteries (27% left) dropped from my setting of 4.5v to 3.6 but putting in a fresh set of fully charged batteries, my voltage didn't drop at all

Something went wrong with your test or what the mod was telling you because there is no such thing as a batteries voltage not sagging under a load. To what degree it sags of course depends on the load and the starting voltage but there will always be a decent amount of sag with the load we put on batteries.

Mooch's test that you posted illustrates that.

Edit:
Your fresh batteries started at 8.4v so setting the mod to 4.5v... no, you didn't see any sag because the sag was not lower than your setting.

 

[SirRichardRear]

Your right, I'm so used to a regulated mod and adjusting watts higher than normal when running a gucci coil instead of a regular round wire coil.



Something went wrong with your test or what the mod was telling you because there is no such thing as a batteries voltage not sagging under a load. To what degree it sags of course depends on the load and the starting voltage but there will always be a decent amount of sag with the load we put on batteries.

Mooch's test that you posted illustrates that.

Edit:
Your fresh batteries started at 8.4v so setting the mod to 4.5v... no, you didn't see any sag because the sag was not lower than your setting.

Yeah good point on that since the g2 is a series mod. Plus regulated mods can have other stuff to stop sag. They don't need to draw directly from the batteries I'm not sure if the G2 does or not

Sent from my SM-G935V using Tapatalk

 

[Scribb|e]

...Plus regulated mods can have other stuff to stop sag. They don't need to draw directly from the batteries...

If not drawing from the batteries, then where from? o_0

(I've not yet heard of any mods that use supercaps, for example, in between the cells and the coils - although that might be an interesting idea.)

 

[fq06]

Yeah, caps would help with the sag but mods do fine even with a sag.

Boost helps a mod get more voltage out than a cell has to offer but it is not close to efficient and 4.5v from a boosted single cell does not vape the same as 4.5v from a multi cell mod.

 

[Scribb|e]

...4.5v from a boosted single cell does not vape the same as 4.5v from a multi cell mod.

Because of PWM, I'm guessing?

 

[SirRichardRear]

If not drawing from the batteries, then where from? o_0

(I've not yet heard of any mods that use supercaps, for example, in between the cells and the coils - although that might be an interesting idea.)

every board is different and we don't really get specs on any of them so it's all just speculation. But I've seen quite a few mods that have a 50 amp limit on 2 20 amp batteries which leads me to believe there is something else sharing the amp load

 

[nightshard]

every board is different and we don't really get specs on any of them so it's all just speculation. But I've seen quite a few mods that have a 50 amp limit on 2 20 amp batteries which leads me to believe there is something else sharing the amp load

The amp limit of a chip and amp limit of a battery are two separate things.

Mod/chip manufacturers may define an amp limit for their chips which means the mod will not let you pass it.
Battery manufacturers publicize amp rating for their batteries which can be passed and may cause damage to the battery but there is no way for the battery to monitor it, it's up to the mod/user to prevent it from being passed.

The current being passed through the battery and the chip is not the same current.

 

[fq06]

Because of PWM, I'm guessing?

Pwm is moderating power to a set amperage or wattage output.

Here's a good explanation of boost

A boost converter (step-up converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. It is a class of switched-mode power supply (SMPS) containing at least two semiconductor switches (a diodeand a transistor) and at least one energy storage element, a capacitor, inductor, or the two in combination. Filters made of capacitors (sometimes in combination with inductors) are normally added to the output of the converter to reduce output voltage [edit: (voltage ripple)]

 

[Scribb|e]

Here's a good explanation of boost...

I get that - I just don't understand how it would lead to:

...4.5v from a boosted single cell does not vape the same as 4.5v from a multi cell mod.

In what way does it 'not vape the same' and by what mechanism?

 

[Scribb|e]

every board is different and we don't really get specs on any of them so it's all just speculation. But I've seen quite a few mods that have a 50 amp limit on 2 20 amp batteries which leads me to believe there is something else sharing the amp load

It's not really 'all just speculation' - even if we don't have the official specs on a lot of the boards that are in use out there, we can easily deduce by seeing what components are used on them the mechanism of their operation.

That a mod that can use 2x20A cells has been limited to 50A doesn't mean anything really, as fq06 already mentioned - a manufacturer might decide to limit the maximum Amp draw of a device to ensure that the components used to build it are kept within safe limits and/or to ensure that the most commonly used cells aren't used beyond their capabilities and also to give them a decent amount of headroom.

 

[SirRichardRear]

It's not really 'all just speculation' - even if we don't have the official specs on a lot of the boards that are in use out there, we can easily deduce by seeing what components are used on them the mechanism of their operation.

That a mod that can use 2x20A cells has been limited to 50A doesn't mean anything really, as fq06 already mentioned - a manufacturer might decide to limit the maximum Amp draw of a device to ensure that the components used to build it are kept within safe limits and/or to ensure that the most commonly used cells aren't used beyond their capabilities and also to give them a decent amount of headroom.

true but again we won't know what the components are. the only company that puts out info on it's board is evolv

 

[fq06]

In what way does it 'not vape the same' and by what mechanism?

Because you are artificially boosting a max 4.2v cell up to... say 4.5v.

With a series mod you are taking a max 8.4v setup down to 4.5.

Like vaping a 0.2 build on a single cell 75w mod at say 70w is much weaker than vaping a dual cell mod at 70w.

 

[Scribb|e]

true but again we won't know what the components are. the only company that puts out info on it's board is evolv

We can tell exactly what the components are, and their exact values and model numbers (or equivalents) in nearly all cases - the only thing that's a bit mysterious sometimes is exactly what certain chips have been programmed to do - the components that actually do all the heavy lifting and real work are easily recognised and categorised by anyone who has some experience of examining electronics.

 

[Scribb|e]

Because you are artificially boosting a max 4.2v cell up to... say 4.5v.

With a series mod you are taking a max 8.4v setup down to 4.5

Why would that affect the quality of the vape, or affect what is seen at the coil terminals using instruments, though?

Surely 4.5V looks (and vapes) exactly the same regardless of whether it has been produced by bucking or boosting a power source?

EDIT: Or, by 'vape the same' were you referring to battery life due to efficiency losses etc?

 

[SirRichardRear]

We can tell exactly what the components are, and their exact values and model numbers (or equivalents) in nearly all cases - the only thing that's a bit mysterious sometimes is exactly what certain chips have been programmed to do - the components that actually do all the heavy lifting and real work are easily recognised and categorised by anyone who has some experience of examining electronics.

OK then show me a schematic on the smok alien with every component or list them.... i'm waiting
Not trying to be a jerk by any means, but the info is rarely out there for 99% of devices. Even if you identify components doesn't mean they will be labeled with model numbers to let you know their specs. Sure you can look at a board if you disassemble it and see a capacitor , resistors, fuses, etc, but you still don't get them complete information from it

 

[fq06]

Why would that affect the quality of the vape, or affect what is seen at the coil terminals using instruments, though?

Surely 4.5V looks (and vapes) exactly the same regardless of whether it has been produced by bucking or boosting a power source?

EDIT: Or, by 'vape the same' were you referring to battery life due to efficiency losses etc?

I added to that post.
Don't know if you've vaped on a 75w single cell mod with a build that needs more than about 40w but after 40w the vape output just isn't the same.

I don't know the technical reason but a single cell just does not put out 75w or even close to it very well.

Like a 0.25 crown coil at 60w on single cell is weak as hell compared to 60w on a dual cell. Even with the same 350j chip in both mods.

 

[SirRichardRear]

No, I added to that post.
Don't know if you've vaped on a 75w single cell mod with a build that needs more than about 40w but after 40w the vape output just isn't the same.

I don't know the technical reason but a single cell just does not put out 75w or even close to it very well.

Like a 0.2 crown coil at 60w on single cell is weak as hell compared to 60w on a dual cell. Even with the same 350j chip in both mods.

depends on the amps in the battery, the single battery won't likely put out 75 watts under most loads. maybe if you built a 1 ohm coil it can, but building a .2ohm coil, your battery won't hold 75 watts. Thats why it feels week.

75 watts is 75 watts, the single battery won't put 75 watts even if you set it to that under heavy load.

 

[Scribb|e]

OK then show me a schematic on the smok alien with every component or list them.... i'm waiting
Not trying to be a jerk by any means, but the info is rarely out there for 99% of devices. Even if you identify components doesn't mean they will be labeled with model numbers to let you know their specs. Sure you can look at a board if you disassemble it and see a capacitor , resistors, fuses, etc, but you still don't get them complete information from it

Sure - if you find a YouTube video, or a blog/forum post where someone has done a teardown of a mod like the SMOK and kindly posted it online, you can easily see what components have been used in it's construction. The important ones, like the capacitors and inductors are quite easy to tell the (even approx) specifications of, and this can be used to tell the useful (or at least *safe*) limits of the design. Like I mentioned earlier, it's often the programmable chips (or sometimes custom ones) that it's hard to tell what they're quite up to exactly, but they aren't the components that do the 'heavy lifting'.

A lot of the components used in mods are SMD (surface mount), which are marked (if you know how to read and identify them) with their specifications.

Or you can do a teardown yourself, if you have the device in your hands.

What is it about the Alien that you want to know that SMOK haven't released the information about?

 

[Scribb|e]

I added to that post.
Don't know if you've vaped on a 75w single cell mod with a build that needs more than about 40w but after 40w the vape output just isn't the same.

I don't know the technical reason but a single cell just does not put out 75w or even close to it very well.

Like a 0.25 crown coil at 60w on single cell is weak as hell compared to 60w on a dual cell. Even with the same 350j chip in both mods.

SirRichardRear is correct (although I think he got his coil resistances the wrong way around) - that is simply because the battery sag when a single cell is taxed at such high loads is too much, and you're not *really* getting that much power using it at those levels.

 

[fq06]

depends on the amps in the battery, the single battery won't likely put out 75 watts under most loads. maybe if you built a 1 ohm coil it can, but building a .2ohm coil, your battery won't hold 75 watts. Thats why it feels week.

75 watts is 75 watts, the single battery won't put 75 watts even if you set it to that under heavy load.

75w with a 1ohm coil is 8.66v.
75w with a 0.25ohm coil is 4.33v but doesn't matter what cell I've tried a single cell mod does not deliver the goods like a dual cell when running a low coil.
They may say it's a 75w device but in real life use it falls on it's face.

 

[SirRichardRear]

SirRichardRear is correct (although I think he got his coil resistances the wrong way around) - that is simply because the battery sag when a single cell is taxed at such high loads is too much, and you're not *really* getting that much power using it at those levels.

75w with a 1ohm coil is 8.66v.
75w with a 0.25ohm coil is 4.33v but doesn't matter what cell I've tried a single cell mod does not deliver the goods like a dual cell when running a low coil.
They may say it's a 75w device but in real life use it falls on it's face.

It's not backwards. It's not really voltage that makes the batteries sag, it's the amperage. but it's all related. a single battery won't put out 7 volts unless the board has a boost. But at 1 ohm and 75 watts it's 8 amps which any battery can handle, at .25 ohms it over 17 amps so if you had a battery less then 20 amps it'll probably sag hard

Sure - if you find a YouTube video, or a blog/forum post where someone has done a teardown of a mod like the SMOK and kindly posted it online, you can easily see what components have been used in it's construction. The important ones, like the capacitors and inductors are quite easy to tell the (even approx) specifications of, and this can be used to tell the useful (or at least *safe*) limits of the design. Like I mentioned earlier, it's often the programmable chips (or sometimes custom ones) that it's hard to tell what they're quite up to exactly, but they aren't the components that do the 'heavy lifting'.

A lot of the components used in mods are SMD (surface mount), which are marked (if you know how to read and identify them) with their specifications.

Or you can do a teardown yourself, if you have the device in your hands.

What is it about the Alien that you want to know that SMOK haven't released the information about?

Nothing I want to know personally. As i said you can make an educated guess but without specs and diagrams you won't be exact. I've worked on plenty of boards in computers, generators and UPS's so close enough doesn't personally cut it for me. Sometimes being off my 1 milliamp is the difference between working and not working.

 

[Scribb|e]

Yes - there's no way that you can get a realistic 75W from a single-cell mod due to the limitations of the cells - you're attempting to draw just too many Amps from that one cell for it to work properly, regardless of it being a decent YiHi chip or whatever. You're just running into the limitations of basic physics in that case.

 

[Scribb|e]

It's not backwards...at 1 ohm and 75 watts it's 8 amps which any battery can handle, at .25 ohms it over 17 amps so if you had a battery less then 20 amps it'll probably sag hard...

Oh I see - yes, of course, you're absolutely right. I was thinking more about the case where a '200W' mod will *just about* put out that Wattage, but only into a coil of a certain resistance (always low and in a *very* narrow range) .but this is more due to the max Voltage limits of the device.

 

[SirRichardRear]

Yes - there's no way that you can get a realistic 75W from a single-cell mod due to the limitations of the cells - you're attempting to draw just too many Amps from that one cell for it to work properly, regardless of it being a decent YiHi chip or whatever. You're just running into the limitations of basic physics in that case.

unless the board has a boost feature and capacitors because many will argue a dual battery mod can't put out 200 watts. yet here we are with smok having a 220 watt dual battery mod. So it's either not really 220 watts or the board has a boost feature

 

[Scribb|e]

unless the board has a boost feature and capacitors because many will argue a dual battery mod can't put out 200 watts. yet here we are with smok having a 220 watt dual battery mod. So it's either not really 220 watts or the board has a boost feature

Well, a dual-cell mod *can* do 220W, but the question really is - can it realistically do so in a useable manner?

According to my calculations, if your 18650s are good for up to 30A - the SMOK Alien, with it's 8V maximum Voltage, could realistically put out 220W into a 0.29 Ohm coil - but the question is - for how long? If it's like all the other 'super powered' mods that have come out so far, it might fire that Wattage into that very specific resistance coil *once*, but that would start to drop off very quickly with all subsequent firings.

 

[nightshard]

Well, a dual-cell mod *can* do 220W, but the question really is - can it realistically do so in a useable manner?

According to my calculations at 220W with 2 batteries you are pushing more then 38A so can you do it? yes, should you do it even with 30A batteries? no and not 200W either.

 

[Scribb|e]

Did I bugger up the calcs?

Looking again, if I factor in a 10% inefficiency , pushing 220W using 8V into a 0.291 Ohm coil presuming the batteries are at a nominal 7.4V in series gives a 33A CDR?

EDIT - And if I give the battery voltage as a fresh-off-the-charger 8.4V in series, that gives a 29.1A CDR - is *this* how SMOK have figured it, I wonder? *Technically* possible with a very specific coil resistance when using batteries just off the charger?

 

[SirRichardRear]

Well, a dual-cell mod *can* do 220W, but the question really is - can it realistically do so in a useable manner?

According to my calculations, if your 18650s are good for up to 30A - the SMOK Alien, with it's 8V maximum Voltage, could realistically put out 220W into a 0.29 Ohm coil - but the question is - for how long? If it's like all the other 'super powered' mods that have come out so far, it might fire that Wattage into that very specific resistance coil *once*, but that would start to drop off very quickly with all subsequent firings.

According to my calculations at 220W with 2 batteries you are pushing more then 38A so can you do it? yes, should you do it even with 30A batteries? no and not 200W either.

One of the cool features on the alien is it shows you amps. So no need to use a calculator. It'll be interesting to see if there is a cut off

With that said most mods recommend a good 20 or 25 amp battery. none recommend 30 amps or higher. there are only a few 30 amp batteries on the market (sony VCT3 and LG HB series) Most people are suing the LG HG2, Samsung 30Q or 25R, or Sony VCT5 which are all 20-25 amp batteries.

I'm gonna play around with the mod and test it a bit and see what happens. My build right now is .17 ohms, at 220 watts that would be a whopping 36 amps. I'm running it at 115W now on my G2 which is 26 amps, and it runs perfect. the G2 does have an amp limit, but hohmtech doesn't publish what it is.

 

[bmclaurin]

what determines voltage? or voltage drop i should say. i was under the impression that the lower the resistance the less the voltage drop.. and why does it change when i change the build?

It doesn't appear that this question was ever really answered directly. In case anyone is interested, following is some info on what "voltage sag" really is.

"Voltage sag" is simply the result of the division of voltage in a circuit amongst its various resistors.

When any battery is put under a load, its voltage will drop (or "sag"). This is because no battery is a perfect, ideal voltage source since they all have some degree of "internal resistance." And in any circuit, the total voltage potential of the voltage source (the battery in this case) is divided amongst the various loads (resistors) that form the circuit, and that division is proportional to their resistance. In the case of a typical vaping device, the total voltage potential is divided primarily amongst (i) the atty/coil/mod and (ii) the internal resistance of the battery itself. And the higher the resistance of the external load (primarily, in our case, the coil), the higher proportion of the battery's total voltage potential that will be applied to it. The rest of the voltage potential is applied to the other resistor in the circuit (the internal resistance of the battery itself). As an aside, when you use a multimeter to measure the open circuit voltage of a battery, you're really just applying the battery across a big resistor built into the multimeter, and the resistance is so high, that practically all of the battery's voltage potential is applied to the external "load" (the multimeter), yet practically zero charge will flow through the circuit (i.e., no measurable current will result) because the resistance is so high, thus yielding a measure of the battery's open circuit voltage (or, electromotive force, or "emf").

If you had a perfect, ideal voltage source (one that, among other things, had no internal resistance) that could supply a constant voltage potential across a given load, then if you measured the voltage across the external load, you would find it to be the exact voltage of the voltage source itself. But if you were using a battery as your voltage source, let's say two fully charged Li-ion cells in series at 8.40v resting voltage, and you applied that across a load with a resistance of, say, 0.5 ohms, you might expect, from Ohm's law, that we would have a current of exactly 16.8 amps (8.4 divided by 0.5), and that we could measure the voltage across the load at exactly 8.40v. Unfortunately, reality is not that simple, nor convenient. Because the battery itself introduces a small amount of resistance to the total circuit, some of the battery's voltage potential will be allocated to the resistance of the battery itself, leaving something less than 8.40v allocated to the external load. If each cell's internal resistance is, say, 0.025 ohms, then the total resistance of the circuit is actually 0.55 ohms (0.50 plus 2*0.025), in which case Ohm's law tells us that we will have only 15.3 amps (8.4 divided by 0.55) (as opposed to 16.8 amps) of current in the circuit. And 15.3 amps through a 0.5-ohm external load means there is only 7.6v (15.3 multiplied by 0.5) across the external load. This is what we mean by "voltage sag." Our example battery, with an open-circuit voltage of 8.4v and internal resistance of 0.05 ohms, will put only 7.6v across our 0.5-ohm external load. From this, we can readily see why batteries with relatively high internal resistance can supply less current than those with relatively low internal resistance.

Hope this helps.

 

[fq06]

That was on the first page, conversion moved past it but more info the better.

 

[SirRichardRear]

That was on the first page, conversion moved past it but more info the better.

FYI got the alien. Fired 220 watts on a .176 build it read out at 33 amps and fired like a champ. Very impressed with jt

Sent from my SM-G935V using Tapatalk

 

[Scribb|e]

FYI got the alien. Fired 220 watts on a .176 build it read out at 33 amps and fired like a champ. Very impressed with jt

Sent from my SM-G935V using Tapatalk

How many Volts did that fire at, do you remember? I'd guess at around 6.2V. I hope you've got some good batteries in your Alien!

 

[SirRichardRear]

How many Volts did that fire at, do you remember? I'd guess at around 6.2V. I hope you've got some good batteries in your Alien!

I think it read 5.6 iirc. Using hb6 batteries. Highest amp limit of any battery, I'll probably test with the HE4 tomorrow

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[Scribb|e]

I think it read 5.6 iirc. Using hb6 batteries. Highest amp limit of any battery, I'll probably test with the HE4 tomorrow

Hmm - 5.6V would represent 31.82A, 178.18 W at the coil (with 10% inefficiency).

 

[SirRichardRear]

Hmm - 5.6V would represent 31.82A, 178.18 W at the coil (with 10% inefficiency).

I don't remember the voltage for sure. Just remember the amps were around 33 and change and the watts at 220.

Also djsl labs did an hour long in depth review. I'm gonna check it out when I get a chance. They said it's capable of 227 watts I heard

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