New here, need an advise on resistance and stuff

[likkichu]

Hey! I'd like to start vaping and I'd really appreciate if someone could explain a few things to me. I have geekvape nova and a couple of sony vtc6 batteries. I can't make coils myself yet so I have just bought some premade. What I didn't account for is that the resistance is split in half if you have two coils connected. So I'm kinda stuck with 0.15 Ohm right now, is it safe or should I just get ones with higher resistance? This is what I can't understand, there are people saying you shouldn't go below 0.4 Ohm having your batteries connected in series. At the same time I hear people going very low with their coils on this mod. How low can I go on this mod and these batteries and stay safe? I have read about the Ohm's law and stuff, but trying to apply it to this particular situation I don't see what makes it work having the resistance this low.
Sorry if this is a silly question.

 

[Beamslider]

Hey! I'd like to start vaping and I'd really appreciate if someone could explain a few things to me. I have geekvape nova and a couple of sony vtc6 batteries. I can't make coils myself yet so I have just bought some premade. What I didn't account for is that the resistance is split in half if you have two coils connected. So I'm kinda stuck with 0.15 Ohm right now, is it safe or should I just get ones with higher resistance? This is what I can't understand, there are people saying you shouldn't go below 0.4 Ohm having your batteries connected in series. At the same time I hear people going very low with their coils on this mod. How low can I go on this mod and these batteries and stay safe? I have read about the Ohm's law and stuff, but trying to apply it to this particular situation I don't see what makes it work having the resistance this low.
Sorry if this is a silly question.

It is a regulated mod. It has protection built in. It should refuse to fire if the ohm is too low. Don't know what wattage you are using but the sony battery you use is 15 AMP battery so not enough for 200 W but you should be able to get 100 Watts out of pair of them without stressing them out.

 

[Punk In Drublic]

Hey! I'd like to start vaping and I'd really appreciate if someone could explain a few things to me. I have geekvape nova and a couple of sony vtc6 batteries. I can't make coils myself yet so I have just bought some premade. What I didn't account for is that the resistance is split in half if you have two coils connected. So I'm kinda stuck with 0.15 Ohm right now, is it safe or should I just get ones with higher resistance? This is what I can't understand, there are people saying you shouldn't go below 0.4 Ohm having your batteries connected in series. At the same time I hear people going very low with their coils on this mod. How low can I go on this mod and these batteries and stay safe? I have read about the Ohm's law and stuff, but trying to apply it to this particular situation I don't see what makes it work having the resistance this low.
Sorry if this is a silly question.

With a regulated device, the regulated circuit separates the battery from the coil. Meaning the battery does not see what the coil resistance is. It only see’s what the device is requesting in terms of power. The higher the power you set, the higher the current draw on the battery. That same 0.15 ohm coil could be ~17 amps at 50 watts or ~34 amps at 100 watts. Just as a simple example single battery.

An easy calculation to determine the max wattage your batteries are able to handle safely is to take the battery CDR rating and multiply that by 3. If using a 2 cell device like the Nova, then multiply that figure by the amount of batteries you have.

Example:

VTC6 = CDR 15amps x 3 = 45 watts x 2 (for a dual cell device) = 90 watts

 

[Hawise]

It's not a silly question at all to be concerned about battery safety. You have got some concepts confused, though. There are basically two types of mods: mechs and regulated mods.

With mechs, power goes directly from the battery to the coil, so the amount of power drawn from the battery depends on the resistance of the coil.

With a regulated mod, like the Geekvape Nova, power goes from the battery to the circuit board to the coil. The amount of power you use depends on your wattage setting.

@Punk In Drublic has explained how to calculate your limits. I'll just add that batteries don't tend to work as well as you get closer to the limit. If you want to vape at 80 - 90 watts, you'd be better off with batteries with a higher CDR. On the other hand, if you're enjoying your coil at less than 50 watts or so, the VTC 6s should work just fine for you.

 

[greek mule]

Geekvape Nova is a regulated dual battery device.Resistance is irrelevant.With these batteries you can go 86W max safely.
Parallel or series configuration is also irrelevant at regulated devices.

 

[likkichu]

With a regulated device, the regulated circuit separates the battery from the coil. Meaning the battery does not see what the coil resistance is. It only see’s what the device is requesting in terms of power. The higher the power you set, the higher the current draw on the battery. That same 0.15 ohm coil could be ~17 amps at 50 watts or ~34 amps at 100 watts. Just as a simple example single battery.

An easy calculation to determine the max wattage your batteries are able to handle safely is to take the battery CDR rating and multiply that by 3. If using a 2 cell device like the Nova, then multiply that figure by the amount of batteries you have.

Example:

VTC6 = CDR 15amps x 3 = 45 watts x 2 (for a dual cell device) = 90 watts

Thank you very much for the detailed answer. So the 3 in this case is the voltage of VTC6 battery, right? Could you explain why we assume it is always 3?

 

[greek mule]

Thank you very much for the detailed answer. So the 3 in this case is the voltage of VTC6 battery, right? Could you explain why we assume it is always 3?

It's the cut off voltage of device.This article explains how to calculate amperage draw at regulated mods.
Calculating battery current draw for a regulated mod | E-Cigarette Forum
Usually the cut off voltage at most regulated devices is 3.2 volt.

 

[ShowMeTwice]

I have nothing to add to the excellent info already provided.
Other than hello and welcome to ECF.

 

[Punk In Drublic]

Thank you very much for the detailed answer. So the 3 in this case is the voltage of VTC6 battery, right? Could you explain why we assume it is always 3?

3 is just the correct factor to multiply the CDR to get a safe estimate wattage for said battery. All batteries in which we use for vaping have an identical voltage of 4.2 max and roughly 2.5 volts min. The minimum voltage is actually lower but 2.5 volts puts us in a safe range. Many devices have a 3.2 volt cut off to keep us well above that min voltage range.

A battery will have a nonminimal voltage, usually around 3.6 to 3.7 volts. This is just the average voltage of the cell (simplified explanation). But the CDR (Continuous Discharge Rate) is the safe amount of current draw a battery is able to handle. You can exceed the CDR of a battery, but run a higher risk of venting or even worse Thermal Runaway. That is why it is recommended to use within the CDR limits of the cell.

With a mechanical and some fixed voltage devices, the resistance of the coil dictates the current draw from the battery. So 0.15 ohms at 4.2 volts could be ~28 amps which exceeds the VTC6 CDR rating of 15 amps. This is where those trying to give you advice are getting confused.

With a regulated device (one that allows a power change), the resistance is separated from the battery and handled by the regulator chip. The chip will dictate what it is able to handle. For the Nova this is 0.05 to 3 ohms (+/- a small variance for discrepancies). Should the chip feel the resistance is un-acceptable it will not fire and give an error.

What determines the current draw on the batteries with a regulated device is the power in which you use it at. The higher the power, the higher the current draw. The current draw also goes up when the battery depletes in order to meet your prescribed wattage. Battery Current = Power/Battery Voltage

It’s actually a little more complex than this for we also need to factor in the efficiency of the device but in the most simplified terms, take the safe recommended CDR of your battery and multiply it by 3, then multiply it by the amount of cells your device has and you get the maximum wattage you can run safely with these batteries.

 

[stols001]

These are some great newcomer questions and you are getting great answers so I will just say Welcome and all that good stuff.

I never thought the double coils, halving resistance was at all fair, and it frankly goes against everything I know about math, but I know extremely little about math.

Happy vaping!

Anna

 

[Punk In Drublic]

These are some great newcomer questions and you are getting great answers so I will just say Welcome and all that good stuff.

I never thought the double coils, halving resistance was at all fair, and it frankly goes against everything I know about math, but I know extremely little about math.

Happy vaping!

Anna

I don’t do math. I refer to my cat which as everyone knows, cats invented math (along with physics). Only problem is given she is missing opposable thumbs, everything is a factor of 4!

 

[Hawise]

Thank you very much for the detailed answer. So the 3 in this case is the voltage of VTC6 battery, right? Could you explain why we assume it is always 3?

As said above, 3.2 volts is a very common cutoff for regulated mods. A fully charged 18650 is 4.2 v, so the range for most regulated mods is 3.2 v - 4.2 v.

Regulated mods draw the most current (amps) when the battery is low. This is because they provide the same wattage regardless of the battery's voltage. When the voltage is high, they don't need as much current to provide the set wattage. As the voltage drops, they need more current to maintain the wattage. We need to know when the current demand is highest so we can tell if it stays under the CDR.

A more precise formula for calculating the maximum wattage for a given CDR is:

Wattage = CDR * 3.2 v * 0.9 * number of batteries

The 3.2 volts is your cutoff, when the current draw is highest. The 0.9 is a 90% efficiency factor. It accounts for two things:

• The power used to run the mod - e.g. light the screen etc.
• Power 'lost' when the board converts the power from the battery into the form you want for the coil, as the process isn't entirely efficient

Anyway, 3.2 * 0.9 = 2.88, so we often just use a factor of three because it's easy to remember and close enough to give you a general idea of where you should be.

Another thing you may be wondering about is how series/ parallel connections affect the calculation. Answer: they don't. If two batteries are in series, voltage doubles. If they're parallel, the CDR doubles. Either way, it's a factor of two so we just multiply by the number of batteries.

Finally, everything I've just explained is for regulated mods only. The rules for mech mods are completely different. For example, series vs. parallel matters very much for mech mods. Also, in a mech the current draw is highest when the voltage is highest, so you would always use 4.2 v in mech calculations.

 

[Hawise]

I never thought the double coils, halving resistance was at all fair, and it frankly goes against everything I know about math, but I know extremely little about math.

In case your cat refuses to check the math for you, you can think of it in terms of logic rather than math. Resistance is just that - it's the force resisting the power as it travels along. In a double coil, you've added an extra pathway the power can use. With a wider (or double) pathway, the power is less restricted, which means less resistance.

Helpful, or complete gibberish?

 

[Punk In Drublic]

In case your cat refuses to check the math for you, you can think of it in terms of logic rather than math. Resistance is just that - it's the force resisting the power as it travels along. In a double coil, you've added an extra pathway the power can use. With a wider (or double) pathway, the power is less restricted, which means less resistance.

Helpful, or complete gibberish?

In @stols001 defence it was me that made the cat reference. But you are correct. 2 bowls of mostly chicken treats, instead of 1, equals less resistance from my cat.

But excellent post.

 

[charlie1465]

Welcome to the friendly (and knowledgeable) bunch

No question is ever ignored here........good luck.

 

[likkichu]

3 is just the correct factor to multiply the CDR to get a safe estimate wattage for said battery. All batteries in which we use for vaping have an identical voltage of 4.2 max and roughly 2.5 volts min. The minimum voltage is actually lower but 2.5 volts puts us in a safe range. Many devices have a 3.2 volt cut off to keep us well above that min voltage range.

A battery will have a nonminimal voltage, usually around 3.6 to 3.7 volts. This is just the average voltage of the cell (simplified explanation). But the CDR (Continuous Discharge Rate) is the safe amount of current draw a battery is able to handle. You can exceed the CDR of a battery, but run a higher risk of venting or even worse Thermal Runaway. That is why it is recommended to use within the CDR limits of the cell.

With a mechanical and some fixed voltage devices, the resistance of the coil dictates the current draw from the battery. So 0.15 ohms at 4.2 volts could be ~28 amps which exceeds the VTC6 CDR rating of 15 amps. This is where those trying to give you advice are getting confused.

With a regulated device (one that allows a power change), the resistance is separated from the battery and handled by the regulator chip. The chip will dictate what it is able to handle. For the Nova this is 0.05 to 3 ohms (+/- a small variance for discrepancies). Should the chip feel the resistance is un-acceptable it will not fire and give an error.

What determines the current draw on the batteries with a regulated device is the power in which you use it at. The higher the power, the higher the current draw. The current draw also goes up when the battery depletes in order to meet your prescribed wattage. Battery Current = Power/Battery Voltage

It’s actually a little more complex than this for we also need to factor in the efficiency of the device but in the most simplified terms, take the safe recommended CDR of your battery and multiply it by 3, then multiply it by the amount of cells your device has and you get the maximum wattage you can run safely with these batteries.

As said above, 3.2 volts is a very common cutoff for regulated mods. A fully charged 18650 is 4.2 v, so the range for most regulated mods is 3.2 v - 4.2 v.

Regulated mods draw the most current (amps) when the battery is low. This is because they provide the same wattage regardless of the battery's voltage. When the voltage is high, they don't need as much current to provide the set wattage. As the voltage drops, they need more current to maintain the wattage. We need to know when the current demand is highest so we can tell if it stays under the CDR.

A more precise formula for calculating the maximum wattage for a given CDR is:

Wattage = CDR * 3.2 v * 0.9 * number of batteries

The 3.2 volts is your cutoff, when the current draw is highest. The 0.9 is a 90% efficiency factor. It accounts for two things:

• The power used to run the mod - e.g. light the screen etc.
• Power 'lost' when the board converts the power from the battery into the form you want for the coil, as the process isn't entirely efficient

Anyway, 3.2 * 0.9 = 2.88, so we often just use a factor of three because it's easy to remember and close enough to give you a general idea of where you should be.

Another thing you may be wondering about is how series/ parallel connections affect the calculation. Answer: they don't. If two batteries are in series, voltage doubles. If they're parallel, the CDR doubles. Either way, it's a factor of two so we just multiply by the number of batteries.

Finally, everything I've just explained is for regulated mods only. The rules for mech mods are completely different. For example, series vs. parallel matters very much for mech mods. Also, in a mech the current draw is highest when the voltage is highest, so you would always use 4.2 v in mech calculations.

It's the cut off voltage of device.This article explains how to calculate amperage draw at regulated mods.
Calculating battery current draw for a regulated mod | E-Cigarette Forum
Usually the cut off voltage at most regulated devices is 3.2 volt.

Thank you very much! You have helped me a lot! I think now I understand how it works, at least in general. One last question though. In this case, the only thing resistance affects in regulated mods is the coil's temperature, and we just choose whatever suits our needs (as long as the mod can handle it of course)?

 

[Punk In Drublic]

Thank you very much! You have helped me a lot! I think now I understand how it works, at least in general. One last question though. In this case, the only thing resistance affects in regulated mods is the coil's temperature, and we just choose whatever suits our needs (as long as the mod can handle it of course)?

In a regulated device what controls the coils temperature is the user. I do not know the specifics of your 0.15 ohm coil, but it could be completely different than the 0.15 ohm coil that I use in terms of type of metal, mass, Specific Heat Capacity, just to name a few variables.

 

[Baditude]

Thank you very much! You have helped me a lot! I think now I understand how it works, at least in general. One last question though. In this case, the only thing resistance affects in regulated mods is the coil's temperature, and we just choose whatever suits our needs (as long as the mod can handle it of course)?

Coil resistance is a non-factor with regulated mods. What matters is the power setting the user uses and the wattage capability of the specific battery being used (based on the amp rating of the battery).

WATTAGE PER SINGLE BATTERY on REGULATED MOD:
(Total wattage doubles using 2 batteries; Triples using 3 batteries.)

Up to 45W:

Samsung 18650 30Q, 3000 mah 15 amp CDR

Sony 18650VTC6 3000mAh 15 amp CDR

Up to 60W:

LG 18650HG2 3000mah 20 amp CDR

LG 18650HE4 2500 mah 20 amp CDR

Samsung 18650-25R, 2500 mah 20 amp CDR

Sanyo UR18650NSX, 2500 mah 20 amp CDR

Sony 18650VTC5, 2600 mah 20 amp CDR

Sony 18650VTC4, 2100 mah 23 amp CDR

Up to 75W:

LG 18650 HD4 2100 mah 25 amp CDR

LG 18650 HD2 2000 mah 25 amp CDR

Samsung 18650-24S, 2500 mah 25 amp CDR

Sony 18650VTC5A, 2500 mah 25 amp CDR

Molicel 18650-P26A, 2600 mah 25 amp CDR

Up to 90W:

LG18650HB6 1500mah 30 amp CDR

LG18650HB2 1500mAh 30 amp CDR

LG18650HB4 1500mAh 30 amp CDR

Samsung 18650-20S 2000mah 30 amp CDR

 

[Hawise]

Thank you very much! You have helped me a lot! I think now I understand how it works, at least in general. One last question though. In this case, the only thing resistance affects in regulated mods is the coil's temperature, and we just choose whatever suits our needs (as long as the mod can handle it of course)?

A number of variables affect coil temperature, but your conclusion is still correct. The rules are:

• Stick within the limits of your mod (regulated mods generally won't fire if you're below the resistance they support)
• Make sure your batteries are suitable for your wattage settings

Other than that, pick whatever coils you like best and vape away.

 

[Zazie]

Mooch is such a good teacher.