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What's the lowest ohm or highest amp I can use with 2 18650 Samsung 25A in smok alien 220W

pricelessvapor

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I'm new to building and I have a Smok Alien 220W box with 2 18650 Samsung 25A batteries. Would I just double what the max amp outputs are so my box puts out 50A? Or to do crazy builds do I need 2 35A battery's? I just ordered 2 RDA's and a RDTA so I want to make sure I'm doing this correctly. Thanks any input will help!
 

shawn.hoefer

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The box is going to prevent any builds too low. I think .1 ohm is the spec...

Sent from my SAMSUNG-SM-N910A using Tapatalk
 

pricelessvapor

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I've been looking it up. I'm using a series box mod and I got 2 Samsung 25R which is only 20A. I'm using a sub-ohm tank with a .15ohm coil and my box says I'm using 20 amps at 65watts. Sooo... Am I pushing my battery's now and if I was to build a .1 coil (once I get the tools and new tank in mail) would I be pushing it?
 

shawn.hoefer

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There is a vast difference between running a build on a series box (mech) and a regulated box with batteries in series.

I applaud you for researching and staying.safe, but, again, with the Alien controlling things, that .1 or .15 build should not be an issue.

Now, if you were to attempt the same build in a series mesh, bad things could happen.



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pricelessvapor

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Ok awesome, thanks for the info. Now I know every single detail and spec about this box lol. At least I know I'm not creating a ticking time bomb, I just really like my hand and fingers. Lmao
 

HondaDavidson

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There is a vast difference between running a build on a series box (mech) and a regulated box with batteries in series.

I applaud you for researching and staying.safe, but, again, with the Alien controlling things, that .1 or .15 build should not be an issue.

Now, if you were to attempt the same build in a series mesh, bad things could happen.



Sent from my SAMSUNG-SM-N910A using Tapatalk
There's a 12amp and almost 70watt difference between .1ohm and .15ohm at 4.2v. 30amps and 300watts at 8.4v. That is a HUGE difference to me.

IDK anything about the Alien 220W.. I assume that because it is 2 batteries it and has a 220w limit or output unregulated it is series. 220 would be .32ohms on a series mod and 26amp. in parallel 220watts would be 58amps and a.08ohm coil. I don't know of any 2 batteries I would want to draw those amps amounts from in either case.

Just remember while your unregulated mod may have some "safety" protections....... Those safety devices are more for protecting the MOD from damage than to protect you. The mod might fire at 50amps even if you insert 10amp batteries. Question is will it stop firing from that battery before or after it vents.
 

SirRichardRear

AKA Anthony Vapes on Youtube
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you'll be fine. the mod protects you. FWIW for shits and giggles i hit my TFV8 tank at 220 watts on my alien to try it out using 20 amp batteries (samsung 30q) and it worked just fine. it was with the .15ohm coil
 

BoomStick

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This is getting old. Coil current and battery current aren't the same thing in a variable wattage mod. And any 2 battery, variable watt mod that goes above about 150 watts uses pwm at the high end of the power range. The amps the mod is showing you is not battery current. It's coil current. With your batteries, use any coil resistance and any watt setting you want.
 

SirRichardRear

AKA Anthony Vapes on Youtube
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This is getting old. Coil current and battery current aren't the same thing in a variable wattage mod. And any 2 battery, variable watt mod that goes above about 150 watts uses pwm at the high end of the power range. The amps the mod is showing you is not battery current. It's coil current. With your batteries, use any coil resistance and any watt setting you want.
I wouldn't say it's getting old. yes it gets asked of a lot but people need this info and not a lot have it. It's good to see people trying to be safe
 

pricelessvapor

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Yea the more I am looking at these mods the more I see why the smok alien 220w box kit was a little cheaper. I have one more question and I'm good to go. This box only goes down to .1 ohm, I saw a few mods that allowed you to go below .1ohm. Do builds ever get that low of ohm? If so what other mods would u recommend?
 

BoomStick

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I wouldn't say it's getting old. yes it gets asked of a lot but people need this info and not a lot have it. It's good to see people trying to be safe
Asking this kind of question isn't getting old, the completely wrong answers being given is getting old.
 

SirRichardRear

AKA Anthony Vapes on Youtube
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Asking this kind of question isn't getting old, the completely wrong answers being given is getting old.
you don't need to get into specifics to explain that a battery is fine. If you want to feel free though. What answer was completely wrong?
Yea the more I am looking at these mods the more I see why the smok alien 220w box kit was a little cheaper. I have one more question and I'm good to go. This box only goes down to .1 ohm, I saw a few mods that allowed you to go below .1ohm. Do builds ever get that low of ohm? If so what other mods would u recommend?
.1 is the standard for 99% of mods in watt mode. very few go lower. most mods do .06 in TC mode only if they have temp control.
Only mods I know of off the top of my head that fire below .1 in watt mode and .06 in TC mode is the hohmwrecker G2 (.007) and Hohmslice (.00001)
very rarely would anyone have to go that low though.
 

HondaDavidson

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This is getting old. Coil current and battery current aren't the same thing in a variable wattage mod. And any 2 battery, variable watt mod that goes above about 150 watts uses pwm at the high end of the power range. The amps the mod is showing you is not battery current. It's coil current. With your batteries, use any coil resistance and any watt setting you want.
You are right... I was thinking the mod was an UNregulated mod.

Yea the more I am looking at these mods the more I see why the smok alien 220w box kit was a little cheaper. I have one more question and I'm good to go. This box only goes down to .1 ohm, I saw a few mods that allowed you to go below .1ohm. Do builds ever get that low of ohm? If so what other mods would u recommend?
Yes people vape at lower than the .1ohm, this mod does. But no you don't need to vape that low, especially with a regulated mod. FWIW this mod will fire down to .06 OHMs when in TC mode. But thats something completely different. In general if you stay within the listed ohm range battery specs and of a mod regulated or unregulated, you will be SAFE. don't have actual specs for your mod but this should be close, http://www.steam-engine.org/modrange.asp
 

SteveZ

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The Steam-Engine thing is interesting but is presenting information from the output end of the chip and doesn't take the battery limits into account at all. For your safety question the best way to look at this is from the battery's point of view. You have two batteries which start at 8.4 volts and drop to 6.4 when drained. Any regulated mod does not care about the resistance where the amp draw from the battery is concerned. It only cares what watts you have set. In your case you set it to 65. Watts equals Volts times Amps. As you drain the batteries the amps have to go up to compensate So 6.4 volts is your worst case. So when you drain the batteries to 6.4 volts they need to supply a little more than 10 amps to pump out the 65 watts you asked for. It will actually pull a little more because there is some loss in the chip but this is still a good way to get a benchmark for comparison. In this case as long as 10 amps is within what you think is safe for your battery then you are good. That should be fine for a 25R which can handle 20 amps continuous if I remember correctly.

In the future when you chose your wattage take it and divide by 6.4 to get the amps and if it is within the safe limit of your battery you should be good to go. 6.4 is a very conservative number. You will never get into trouble using it but I usually use 7.2 to get a median amp value.

So how come your mod said 20 amps? Well at 65 watts and 0.15 ohms, 20 amps is what appears to go through the coil. It also probably said the volts was 3.1 because that is the correct volts for that watts/ohms combination. you can say the chip trades volts for amps to get the 65 watts but that is at the coil side of the chip and doesn't tell you anything about what strain is being put on the battery. Now the chip does have output limits which seemed to be what everyone was talking about but that didn't seem like what you were asking about.

This was a little longer than I had hoped but the important thing is to stay safe. With your 25Rs you are well within their specs at 65 watts but if you substitute a cheap-ass pair of 10amp batteries then you are on the edge and should know how to tell when you are about to go over.
 

robot zombie

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you can say the chip trades volts for amps to get the 65 watts but that is at the coil side of the chip and doesn't tell you anything about what strain is being put on the battery.
Honestly, this confounds me. Why mods will tell you everything but what is being drawn from your batteries is simply baffling. The readouts they do give really don't mean much of anything, save for the wattage and resistance, I suppose.

I feel like this in itself causes a lot of confusion. A lot of people out there fundamentally don't understand how their regulated mods work. The majority of people seem to think they're like a mech mod and go by the power running to the coil. They look at those numbers and think that reflects what's happening on the battery end. Even a lot of experienced vapers operate under this assumption.

How tricky is it, really, to design a mod that takes the battery voltage readout (which they all take anyway,) divide the wattage set by that number and show the amp load on the batteries on the screen? It's a fundamental safety feature, is it not?

No matter what coil, what resistance, or what voltage is shown on the screen, the amp load on your batteries in a regulated device is always wattage / battery voltage. It's W / Vb = A. Forget everything you know about ohm's law. It doesn't apply to your batteries in regulated devices. The coil doesn't matter. Only the wattage does.
 

shawn.hoefer

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Member For 4 Years
There's a 12amp and almost 70watt difference between .1ohm and .15ohm at 4.2v. 30amps and 300watts at 8.4v. That is a HUGE difference to me.

IDK anything about the Alien 220W.. I assume that because it is 2 batteries it and has a 220w limit or output unregulated it is series. 220 would be .32ohms on a series mod and 26amp. in parallel 220watts would be 58amps and a.08ohm coil. I don't know of any 2 batteries I would want to draw those amps amounts from in either case.

Just remember while your unregulated mod may have some "safety" protections....... Those safety devices are more for protecting the MOD from damage than to protect you. The mod might fire at 50amps even if you insert 10amp batteries. Question is will it stop firing from that battery before or after it vents.
the device has limits on the amps it will draw.

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shawn.hoefer

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Yes.. but if that limit is higher than the batteries.......... then what?

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then the batteries can potentially become damaged. However, the OP stated Samsung 25R, so... All should be fine...

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SirRichardRear

AKA Anthony Vapes on Youtube
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Yes.. but if that limit is higher than the batteries.......... then what?

Sent from my SCH-I605 using Tapatalk
the device doesn't draw directly from the batteries. this si one of the best write ups i seen explaining it (stolen from reddit https://www.reddit.com/r/electronic...you_dont_calculate_current_draw_on_regulated/)

Regulated mods typically use a DC-DC converter (probably in most cases a switched-mode converter). That is, they separate the input and output voltage (in other words, they separate the battery from the atomizer). So, just because you have 3.7v going in from your battery doesn't mean this is what will be hitting the atomizer. On a mech mod, yes, that is what happens because there is nothing in between the atomizer and the battery. On a regulated mod, there is a voltage regulator in between the battery and the atomizer.

On a mech mod, as your battery drains, you have less voltage (and thus less power) hitting the atty. This means the vapor production diminishes over time. We know from Ohm's law that Power = voltage X current. As you can see from this simple equation, as the voltage drops, this necessarily means less power (watts).

The circuitry in a regulated mod stops this from happening. The regulator will swap voltage for current in order to achieve the power (watts) you have your mod set at. Again, P = I * V. As the voltage on the right side of the equation drops, the power also must drop. So, looking at this equation, how can we keep the power constant throughout the charge of the battery? Yep, we need to increase the "I" (current) to compensate for the battery being drained. This will allow you to keep your desired power setting all the way through the battery's charge.

So let's cut to the brass tacks. If you want to know the current being drawn from your battery on a regulated mod, you need to solve the equation for I (since the value of I is what you want). The equation for current is: I = P/V. That is, Current = Power/Voltage. Voltage will be a fixed parameter (and it will depend on the charge of your battery) and power is easy enough to see on your mod's screen. (Some mods also show the remaining battery charge in volts, which comes in handy for this. If not, you will have to guess, but 3.7v is a good "guess" for a battery that's not low).

Example: Let's say you have your mod set at 50 watts and your battery has about a 3.7v charge on it. Thus: 50/3.7 = 13.5 amps. If you have your mod set to 50 watts and you have a (relatively) fresh battery, you are going to be pulling 13.5 amps no matter what the resistance of your coil is.

But, for the sake of argument, let's say your coil is a 0.5Ω kanthal build. What most people would do would be to go to an online calculator and input the resistance of their coil and their power (watts). If you did this, the current draw would be shown as 10 amps (which is incorrect). Why is that incorrect? Because the voltage required to make that work is 5v. None of our batteries can output 5v (unless they are in series) or unless the regulator is increasing the amp draw to make those 5 volts. And the regulator will have to increase the amp draw to make that work, so in reality you are drawing 13.5 amps (as I showed in my original calculation), not 10 amps. The same result will happen if you input the output voltage and resistance. You will get back 10 amps, which is incorrect.

I think the biggest bit of confusion comes from the fact that people don't know the difference in input voltage (what comes directly from the battery and varies based on charge level) and output voltage (what the regulator puts to the atomizer to achieve your desired power level). And the mods we use don't help the matter. A lot of these mods show the power, the resistance of the coil and the applied voltage on the screen at the same time. So, a lot of people assume this is the voltage value you plug into an Ohm's law equation. Using our .5Ω example, if you had it set to 50 watts, the screen would show 5v. So if you plugged in 5v and 0.5Ω into a calculator, you would once again get back the incorrect result of 10 amps.

I saw a guy earlier who was talking about his build on a regulated mod. He said "I am running 0.3Ω at 80 watts. This equals 16 amps, so I am well within the safe limits of my 20 amp battery." Well, he committed the cardinal sin of using the output voltage in his calculation (or using Power and atomizer resistance to calculate current -- neither are correct). Let's do his calculation properly. If his battery is fully charged (around 4v) and he is running at 80 watts, then:

I = P/V

80/4 = 20 amps.

In reality he is pulling 20 amps on a full charge, not 16 as he thinks. But that's not all. Since the battery voltage drops during use, the regulator will have to increase the amperage drawn to keep him at 80 watts. So, let's say his battery is near dead and is at 3.2v.

80/3.2 = 25 amps

Now, since most batteries are 20 amps continuous, we might be getting into some danger territory (possibly). Meanwhile this guy is vaping happy thinking he is still only pulling 16 amps from the battery.

Multiple Battery mods:

Some mods will run multiple batteries in series or parallel. First we need to explain the difference:

A series connection will treat the two batteries as one. The advantage of a series connection is the voltage doubles (from 3.7v nominal to 7.4v nominal). This means you will, in a sense, be putting less stress on the battery. For instance, if you were to run 100w with a 3.7v battery, you are drawing 27 amps on a fresh battery. If, however, you have two batteries in series, you will only be drawing 13 amps. Remember, in series, the two batteries behave as one. Therefore, the amp limit of one battery is the amp limit of both batteries (25R's in series still have a 20 amp limit). However, with the doubled voltage, you don't need as much current to achieve the desired power. So, even though the amp limit hasn't magically doubled, the need for those amps has decreased.

Parallel configurations do not double the voltage. Two 3.7v batteries in parallel still only provide 3.7v. However, the capacity of the cells (amp hours) is doubled. This also means that the amp limit will also double (from 20 amps for one battery to 40 amps for two, and so on). So, if you want 100 watts with parallel batteries, you will still only be applying 3.7v to achieve it, which means you are drawing 27 amps on a fresh battery. But since you have two batteries with a 20 amp limit, the 27 amps is well within that 40 amp margin of safety.

Essentially, as far as current draw is concerned, series and parallel achieve the same thing. It's just the way they achieve it is different. Series achieves it with more voltage (which decreases the need for more current), while parallel achieves it by doubling the amp hours (increasing the available current).

Example: You are running your Sigelei 150 at 150 watts and you want to know the amp draw on your batteries.

I = 150/ 7.4v = 20 amps

Since your two batteries become a single battery in series, the nominal voltage effectively doubles. This means you don't need as much current to hit that 150 watts.

TL;DR: Don't confuse output voltage for input voltage on regulated mods. If you want to determine your current draw from the battery on a regulated mod, here is the only correct way to do it: I = P/V. That means your current will equal your watt level divided by how much charge you have on your battery. If you don't know the charge, then just plug in 3.7v (as that's the nominal rating). Atomizer resistance has nothing to do with the current being drawn from your battery on a regulated mod.

EDIT: Looks like I was late. Another guy wrote this same PSA a while back. I recommend reading his as well.

EDIT #2: /u/D-juice comments are also relevant:

max amps = max watts/2.5v

For multi-battery mods divide that by the number of batteries (the maths works the same in parallel and series).

His equation provides a bit of a safety margin, so you can use 2.5v as a "rule of thumb" number to calculate the amperage being drawn from an almost depleted battery. Also, you need to factor in efficiency (~10% overhead) as well depending on the board (check your board's specs for efficiency).
 

SirRichardRear

AKA Anthony Vapes on Youtube
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another one from reddit
This is something I've been meaning to post for a while, because pretty much every day I see numerous occurrences of people miscalculating this number. With regulated devices being so ubiquitous now, I think it's extremely important to help people to get out of the mech mod mindset to avoid potentially costly mistakes.

So let's dive in!

What is input current?
Input current is the amount of current drawn by the regulator in a regulated devices from the batteries needed to provide the output power selected by the user.

This number is important because it tells us what kind of batteries we need to use for our devices to power them safely.

Power in equals power out.
Energy cannot be created nor destroyed, only converted. Assuming you're within the operating parameters of your device, if you output 50w, you will draw that same 50w from your batteries.

In a regulated device, you can think of the electrical system as having two separate sides joined together by the regulator chip. One side is the input side - this circuit is between your batteries and the chip. The other side is the output side, which is between the chip and your atomizer. The number that links these two sides together is power (watts), and only power.

Ok, so how to we calculate input current?
To calculate your input current, you need ohm's law and two numbers. The example here will use a Sigelei 100w as the device, with a pair of Samsung 25R batteries.

The first number is the power in watts. This is the output wattage your have your chip set to. For this example let's use an output wattage of 100w. For safety reasons, to factor for the conversion loss of the regulator, add 10% to your power number. That gives us a total of 110w that needs to be drawn from the batteries to supply our regulator.

The second number we need is the battery voltage. This number depends on your battery configuration. We will be using the nominal voltage of our batteries for this calculation. For the 25R that happens to be 3.6V, but since our devices uses these two batteries in series, we need to double that number. That gives us a total nominal input voltage of 7.2V.

Now the rest simply involves plugging the numbers into ohm's law. Current (amps) = Power (watts) / Voltage (volts). 110W / 7.2V = 15.3A.

As you can see, to get our total of 110W out of a pair of batteries in series, our regulator will need to draw about 15.3A. This is well within the 20A continuous discharge rating of these cells, and is thus well within safe limits.

And as a bonus, answers to a few related questions.

What about resistance?
If I asked most people which resistance would give me better battery life running at the same wattage, 0.5ohms or 1.5ohms, most people would answer 1.5ohms. In actuality, both resistances will have the same battery life. Since battery life is determined by power, the regulator will draw the same current from the battery regardless of the resistance.

Parallel vs series?
Another common misconception is that 'parallel doubles your battery life', but in fact regardless of configuration any two battery setup will double the battery life versus a single battery.
 

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