How does resistance affect battery drain?

[BernieVideo]

Reading these forums have informed me a lot about electricity. DC at least.

I just read something in another thread that confused me. I guess I am confused/ignorant on several issues. So here are my questions.....

1. Given that you are running two different ohm coils at the same wattage. Which uses the battery faster, a 1.8 ohm or a 2.5 ohm coil?

In my mind, higher resistance means you need to pump more voltage to get the same watts, thus using the battery faster. Right or way wrong?

2. Does the resistance of a coil change over time, or from heavy use? Does chain vaping heat the coil to the extent that it alters it's resistance? Does the act of heating then cooking then heating affect the resistance of a coil? A bit or more than a bit?

I guess that's all my questions. For now.

Funny how something I desperately sought to help me quit smoking has led me to want to learn stuff.





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[Switched]

Q1 Think resistance as a tap, the lower the resistance the wider the tap is open, draining your bucket quicker.

Q2 Yes and no.

 

[BernieVideo]

Q1 Think resistance as a tap, the lower the resistance the wider the tap is open, draining your bucket quicker.

Q2 Yes and no.

I understand that less resistance is exactly that. Less resistance allows more flow, faster flow, than more resistance.

But my question was crouched in watts. Target watts.

So let me ask it a different way.

Will running my VV at 3.7 volts drain the battery slower than running it at 4.5 volts? Keeping in mind that both settings are aimed at delivering the same watts. Or will they be the same?



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[DaveP]

Here's a calculator that lets you enter voltage and resistance and see the wattage and current draw for yourself. Click the Ohms Law Wheel in the sidebar to see the actual formulas.
Ohm's Law Calculator

Power (watts) = voltage X amperage.

Amperage = Voltage / Resistance

So, if you have a 2 ohm atty running at 4 volts, the amperage draw will be 4/2 or 2 amps. Change that to a 3 ohm atty and the amperage draw will drop to 4/3= 1.33 amps.

Once you know the amperage and the voltage, you can calculate wattage.
4 volts at 2 amps = 8 watts.
4 volts at 1.33 amps = 5.32 watts.

In answer to your questions ...

1. Given that you are running two different ohm coils at the same wattage. Which uses the battery faster, a 1.8 ohm or a 2.5 ohm coil?

In my mind, higher resistance means you need to pump more voltage to get the same watts, thus using the battery faster. Right or way wrong? This is only true when you are trying to get a hotter vape out of a specific coil. You example specified the SAME wattage on BOTH cols. Wattage is the measurement of power draw, so in your example each is the same wattage, thus equal battery draw.

2. Does the resistance of a coil change over time, or from heavy use? Does chain Vaping heat the coil to the extent that it alters it's resistance? Does the act of heating then cooking then heating affect the resistance of a coil? A bit or more than a bit?

At the same wattage, battery life will be the same for 1.8 ohm and 2.5 ohm coils because a voltage adjustment is necessary to make both those coils draw the same wattage.

Coils can change resistance slightly with temperature and that's why smart mods apply voltage when they measure the coil and report the resistance reading. Coils can also change resistance over time as the leads develop resistance where they are attached. Most heads get contact from a silicone sleeve that presses them against the center and outer contacts of the head assembly. Solder is suspect in anything that's heated and inhaled, IMO.

Cartos may use a silicone sleeve with a metal inner contact for pressure against the wire or they may use pressed metal contacts with the wire pressed into a small tube connector. Silicone and a sleeve is most common.

 

[sawlight]

This is difficult to answer! With a standard battery, no VV involved, the higher the resistance the less amps are drawn. With VV you crank up the voltage to get the same heat you get with the lower resistance and the math says you are using less amps, but with a single battery you are using a boost circuit so the battery voltage is a constant so it sees the same load. Then you have a loss of around 15% in the circuit. With a stacked battery mod you have a higher input voltage and you use a buck circuit to drop the voltage so the batteries see the load the math shows with less loss in the circuit.
Good and confused now?

 

[BernieVideo]

At the same wattage, battery life will be the same for 1.8 ohm and 2.5 ohm coils because a voltage adjustment is necessary to make both those coils draw the same wattage.

Thank you, this is what I thought. Simple math.
(I will admit I have been buying low resistance coils thinking I would be using my battery less, but I know realize now I was being a .....)

This leads me to think that offering different resistant coils on the same atomizer is only important/relevant to those not using a variable voltage/wattage battery. Since I use a VV, it really doesnt matter which resistance coil I get as long as I make the appropriate choice of voltage.

Very illuminating!

 

[Hoosier]

1. Given that you are running two different ohm coils at the same wattage. Which uses the battery faster, a 1.8 ohm or a 2.5 ohm coil? ...

The thing that seems to confuse some folks when it comes to VV or VW is that the battery is a power source. (Not a voltage or current source.) Since the battery has a fixed voltage and power is a product of voltage and current, we generally speak of batteries in terms of current, but it's still a power source.

So it stores power and you use power, but since there is a fixed voltage we refer to the number of Amp hours it holds. As far as the battery is concerned, 7 Watts is 7 Watts. Increased voltage does not come from a magic reserve, it is created from additional current draw from the battery by a boost circuit.

To get technical there are inefficiencies when the battery voltage is decreased (bucked) or increased (boosted) which results in a bit more power consumed to create the output power. How much depends on the buck/boost circuit, but most will not consume nearly as much power as a resistance coil like we use for vaping so the impact on battery charge life will be difficult to measure without proper equipment. So the resistance and wattage setting that output a voltage as close to the battery's normal voltage will result in a slightly longer charge life. (Since that can be done without a buck/boost circuit, it seems rather odd to "want" to do this.)

 

[Switched]

The thing that seems to confuse some folks when it comes to VV or VW is that the battery is a power source. (Not a voltage or current source.) Since the battery has a fixed voltage and power is a product of voltage and current, we generally speak of batteries in terms of current, but it's still a power source.

So it stores power and you use power, but since there is a fixed voltage we refer to the number of Amp hours it holds. As far as the battery is concerned, 7 Watts is 7 Watts. Increased voltage does not come from a magic reserve, it is created from additional current draw from the battery by a boost circuit.

To get technical there are inefficiencies when the battery voltage is decreased (bucked) or increased (boosted) which results in a bit more power consumed to create the output power. How much depends on the buck/boost circuit, but most will not consume nearly as much power as a resistance coil like we use for vaping so the impact on battery charge life will be difficult to measure without proper equipment. So the resistance and wattage setting that output a voltage as close to the battery's normal voltage will result in a slightly longer charge life. (Since that can be done without a buck/boost circuit, it seems rather odd to "want" to do this.)

Hey good buddy LTNS. What ^^ he said^^

 

[Switched]

Reading these forums have informed me a lot about electricity. DC at least.

I just read something in another thread that confused me. I guess I am confused/ignorant on several issues. So here are my questions.....

1. Given that you are running two different ohm coils at the same wattage. Which uses the battery faster, a 1.8 ohm or a 2.5 ohm coil?

In my mind, higher resistance means you need to pump more voltage to get the same watts, thus using the battery faster. Right or way wrong?

2. Does the resistance of a coil change over time, or from heavy use? Does chain Vaping heat the coil to the extent that it alters it's resistance? Does the act of heating then cooking then heating affect the resistance of a coil? A bit or more than a bit?

I guess that's all my questions. For now.

Funny how something I desperately sought to help me quit smoking has led me to want to learn stuff.





Tapatalking on iPhone.
Join the CASAA.
Protect your Vaping Rights!

Here's a calculator that lets you enter voltage and resistance and see the wattage and current draw for yourself. Click the Ohms Law Wheel in the sidebar to see the actual formulas.
Ohm's Law Calculator

Power (watts) = voltage X amperage.

Amperage = Voltage / Resistance

So, if you have a 2 ohm atty running at 4 volts, the amperage draw will be 4/2 or 2 amps. Change that to a 3 ohm atty and the amperage draw will drop to 4/3= 1.33 amps.

Once you know the amperage and the voltage, you can calculate wattage.
4 volts at 2 amps = 8 watts.
4 volts at 1.33 amps = 5.32 watts.

In answer to your questions ...



At the same wattage, battery life will be the same for 1.8 ohm and 2.5 ohm coils because a voltage adjustment is necessary to make both those coils draw the same wattage.

Coils can change resistance slightly with temperature and that's why smart mods apply voltage when they measure the coil and report the resistance reading. Coils can also change resistance over time as the leads develop resistance where they are attached. Most heads get contact from a silicone sleeve that presses them against the center and outer contacts of the head assembly. Solder is suspect in anything that's heated and inhaled, IMO.

Cartos may use a silicone sleeve with a metal inner contact for pressure against the wire or they may use pressed metal contacts with the wire pressed into a small tube connector. Silicone and a sleeve is most common.

In the case of "wattage" ""Power"" as Dave stated, you will be in the same ball park. As Hosier stated in part, it is better to boost a circuit than it is to buck a system wrt battery life.

 

[Thunderball]

I have a really strange urge to charge all my batteries now......

 

[Switched]

Wrt the VV and VW devices out there, the best coil to use iMHO is a 2.5Ohm = greatest versatility for battery life. Albeit you can run a 1.5Ohm coil at 8 watts, it will not last as long as a 2.5Ohm at 8 watts. Mind you, you will be recharging your batteries pretty much at the same rate, but not replacing coils ate the same rate. Ohm's law is your friend

Without disrespect, the way you ask your Q depends on the answers you will receive.

 

[Ryedan]

Since I use a VV, it really doesnt matter which resistance coil I get as long as I make the appropriate choice of voltage.

The choice of resistance may matter with a VV device in that you want to be able to achieve the power (watts) you want to vape at with the volts you have available to set.

So if you have 3 - 6 volts available and you buy a 3 ohm atty, your power range is 3 to 12 watts.

With a 2 ohm atty your power range is 4.5 to 18 watts.

Both these ranges are probably fine for most people. Some people using some juice delivery devices may prefer to be in the lower or higher range though. And you can get 1.5 ohms and 4 ohms also.

 

[Switched]

The choice of resistance may matter with a VV device in that you want to be able to achieve the power (watts) you want to vape at with the volts you have available to set.

So if you have 3 - 6 volts available and you buy a 3 ohm atty, your power range is 3 to 12 watts.

With a 2 ohm atty your power range is 4.5 to 18 watts.

Both these ranges are probably fine for most people. Some people using some juice delivery devices may prefer to be in the lower or higher range though. And you can get 1.5 ohms and 4 ohms also.

... to add to that....

A long long time ago I found my sweet spot to be 8W. Something hard to achieve with what we had to play with! Now I simply set my SW (sweet spot) and regardless what I put on my "device" it produces 8W. .... man! You should have been around for the arguments between "provari" and the "evolv" in the day? You know what camp I am in

 

[DaveP]

Thank you, this is what I thought. Simple math.
(I will admit I have been buying low resistance coils thinking I would be using my battery less, but I know realize now I was being a .....)

This leads me to think that offering different resistant coils on the same atomizer is only important/relevant to those not using a variable voltage/wattage battery. Since I use a VV, it really doesnt matter which resistance coil I get as long as I make the appropriate choice of voltage.

Very illuminating!

Years ago, changing atomizer resistance was the only way to vary the vape. Then, variable voltage mods came along and suddenly we had volume controls for our vapor. If you buy a VW mod you can set it in power mode and change coil resistance without making changes to the settings on your mod.

As was pointed out, there is some small loss associated with the circuitry that bucks or boosts the voltage due to the methods used to power the electronics and the need to discard unused current through heat produced by the process of regulating the voltage. The most efficient use of battery power is to use a mechanical mod and change atomizer resistance to control the vape. It's just more convenient to dial what you want.

 

[CraftyZA]

Make this image larger, and print it. Stick it on the wall where you do your vape setups...

 

[Switched]

The choice of resistance may matter with a VV device in that you want to be able to achieve the power (watts) you want to vape at with the volts you have available to set.

So if you have 3 - 6 volts available and you buy a 3 ohm atty, your power range is 3 to 12 watts.

With a 2 ohm atty your power range is 4.5 to 18 watts.

Both these ranges are probably fine for most people. Some people using some juice delivery devices may prefer to be in the lower or higher range though. And you can get 1.5 ohms and 4 ohms also.

... true, but that 2Ohm atty will pop at 6V, so that range is really not there.

In the day a 2.5Ohm at 5V gave a better vape than a 1.5Ohm at 3.7V. The LR was suppose to mimick 5V vaping.

 

[DaveP]

... true, but that 2Ohm atty will pop at 6V, so that range is really not there.

In the day a 2.5Ohm at 5V gave a better vape than a 1.5Ohm at 3.7V. The LR was suppose to mimick 5V vaping.

I've been vaping long enough to try pretty much all the permutations of hardware and I have yet to find a 3 ohm atomizer/cartomizer/tank or anything that doesn't approach burning taste at 5v. 6 to 7 watts is my sweet spot and I sometimes drop to 5w if the vape is better. I always thought that whatever those 5v guys were vaping was inefficient if it took 5 volts to reach the sweet spot.

That's just my personal opinion. I drop to 3.3v on a 2 ohm coil and blow clouds of sweet vapor. If it's 3 ohms I'm at 4.2v.

 

[Switched]

I guess you are not one in the sub-ohm crowd

 

[DaveP]

I guess you are not one in the sub-ohm crowd

Not with a VV/VW mod. I'm also allergic to spewing battery juice. (just a joke). Pushing battery current to high levels is unavoidable with the amp draw I've heard sub ohm guys talk about. Do you worry about acrolein production with sub ohm vaping?

 

[Switched]

Not with a VV/VW mod. I'm also allergic to spewing battery juice. (just a joke). Pushing battery current to high levels is unavoidable with the amp draw I've heard sub ohm guys talk about. Do you worry about acrolein production with sub ohm vaping?

Dave,

I hear you good buddy No I am in your camp With the advent of VW I am not sure what folks are doing these days besides following the crowd

Remember Nuck? Cisco and he used to exchange in some serious discussions. the vaping range was between 6-12W 9 being the sweet spot. <---- The MID from Janty was what Cisco was working on in 2010.

There are times I wonder why I even participate on the forums these days?