Help choosing atomizer resistance

[VapinSweetZ]

My BDC comes in 3 variations, 1.6, 1.8 and 2.1 ohms,
I'm using VV V3, so I can give it up to ~5v if needed.

Can you please explain when is it better to use low resistance and when high resistance with VV bateries?
I know the difference when using a fixed voltage battery, but if I'm using a VV I'm not sure I understand the differences between low resistance+low voltage vs. high resistance+high voltage if the wattage is anyway the same.

Edit: my guess is high resistance with VV battery will only give me a wider range of low wattage options, because anyway the max wattage will be the same with both of them, I guess the liquid will have a burn taste before it's really effect the atomizer lifespan (the differences in amps is kinda small in most situations, 1.95A vs 2.1A on 8W and 2.2A vs 2.35A on 10W when comparing 1.8 to 2.1ohms).

On the other hand, if anyway the liquid will limit me before the atomizer's life, maybe it's even better to go with 1.6ohm, that way I can use a lower voltage to reach the same wattage and get longer battery life (between charges).


Thanks!

 

[Wmmeese]

In the end, it all about the energy you put into the coil. Energy is measured in watts, and is is directly proportional to amps and volts, but for amps, it is the square of the amp value. The higher the ohm value of the coil, the more watts you need to achieve the same amps. For a set energy (watts), lower ohms means lower volts and higher amps. Subjectively, most people with vv/vw devices prefer ohms around 2.0 ohms (1.8 - 2.2). People with mechs and low ohms are chasing vapor production running wattages above 10. Most times this causes a sacrifice of flavor as the coil temperature can break down the juice in addition to vaporizing it. For fixed batteries like the EGO and your Vv, it is not recommended you go below 1.5 ohms as the battery is not made for such a low load. Hope this helps and not confuses you.

 

[maybeshewill]

This, pretty much.

Also, some little minor tips

*Thicker/more viscous juices can take a higher voltage. But keep your ressistance and the above chart in mind
*Stronger juices in flavor (cigar, pipe, aromatic blends), and candy flavors (cinamon cookies, caramel) can also take a higher voltage, usually.
*This doesn't cover all the potential volt inputs, so if you're using a vision/smok/ego-c, twindle about till you find your desired effect. It's all a personal experience.

 

[VapinSweetZ]

Thanks! great reply just it doesn't answer my question that much.

I can see from the chart that the sweet spot in any combination is always around 8.5w.

So with a 1.6 ohm, 1.8 and 2.1 ohm options, I can set the battery to 3.5v, 3.8v or 4.1volts and reach the same 8.5w heating level.

But what's gonna be the differences with each one of the settings?

 

[f1vefour]

On a VV/VW device it doesn't really matter what ohm your coil is, it's why it is variable. You can get the same vape from a 1.5 ohm as a 3.0 ohm, the only difference is how much power it takes to get there.

 

[VapinSweetZ]

Thanks, so what does more power means to me?
Less battery life?
Less atomizer lifespan?

 

[f1vefour]

Thanks, so what does more power means to me?
Less battery life?
Less atomizer lifespan?

Hard to say really, lower ohms use less voltage but more amperage. I would say lower resistance equals less battery and coil life.

On a mild mannered device such as yours the longevity of the battery/coil is likely negligible over the various ohm range of your coils. Or put simply, I wouldn't worry about it

 

[VapinSweetZ]

It's more out of curiosity than actually relevant for me right now
I went to order new atomizer heads and was curious about the difference between 1.6/1.8/2.1 ohms

Anyway, just for my information, what's the safe amperage range for standard coils (prebuilt atomizers).
Because 1.6 ohm will get about 2.3amp on 8.5w (3.6v) and 2.5amp on 10w (4v).
2.1 ohm on 8.5w gets about 2amp (4.2v).

They all sound pretty safe to me, but I don't really know that


Thanks!

 

[f1vefour]

Whatever is the maximum amp limit of your battery/mod is the safe range. Your device shouldn't fire a coil that would exceed the amp rating of the internal battery.

 

[MorpheusPA]

Theoretically, low ohms and low voltage will drain a battery at the same speed as high ohms and high voltage (the math gets a little complicated, so this blanket statement is extremely arguable but generally close enough to true. Suffice to say it's easy to build an exception to the rule, but that exception won't impact most users).

In reality, a whole bunch of things come into play, but they shouldn't impact battery life all that much. Our voltage converters should be switching rather than linear, so efficiency is fairly high--high enough that I'm not going to spend any time worrying about it on my stuff, anyway.

 

[VapinSweetZ]

Whatever is the maximum amp limit of your battery/mod is the safe range. Your device shouldn't fire a coil that would exceed the amp rating of the internal battery.

The VV V3.0 rated as max 3.5 amper, is 3.5A safe to use constantly with a standard Clearomizer?

 

[f1vefour]

The VV V3.0 rated as max 3.5 amper, is 3.5A safe to use constantly with a standard Clearomizer?

It would be, your running within spec of the device.

 

[VapinSweetZ]

It would be, your running within spec of the device.

Are you sure about that? I'm far from expert but 3.5A sound like it's gonna fry my atomizer :X

 

[MorpheusPA]

Are you sure about that? I'm far from expert but 3.5A sound like it's gonna fry my atomizer :X

3.5A at 3.3 volts would only be 11.6 watts, or usable. A bit high, and definitely frying delicate liquids, but usable.

3.5A at 4.2 volts, or maximum draw off a fully charged battery, would give 14.7, which would be an atty killer.

The actual draw off the battery will be determined by the resistance of your atomizer and the settings on the VV. In wattage mode, it limits you to 11. In voltage, to 5.0--and it'll probably amperage limit you to 3.5 A no matter what atty you're using.

To generate 3.5 A at 5.0 V, you'd need an atomizer with a resistance of 1.4, and that would overstep a 3.5 A battery (which is actually a nominal 3.7 volts and trying to generate a little more than 4.7 A). The battery's protection would kick in, assuming you don't hit the wattage limit on the device, which you probably would.

Personally, I'm a fan of never getting anywhere close to testing a battery's protection circuit (if any) as they can fail, and I'd go with a battery that can generate at least 5A minimum. That's why I tend to like IMR batteries in mods.

 

[f1vefour]

Are you sure about that? I'm far from expert but 3.5A sound like it's gonna fry my atomizer :X

You can't hit 3.5 amps likely, you would need to be running a 1.4 ohm coil @ 4.9 volts. And sure it can fry an atomizer, you will know because you will taste it burning.

In other words you would have to be trying to burn up a coil.

Use the device in variable wattage and you have nothing to worry about.

 

[RJ32]

resistance is measured in ohms the higher the ohms the more volts you can apply
if u had a e.g 3.0 ohm atty you would find it takes longer to heat up with small volts such as 3 volts
a 1.8 resisted atty will take up to around 6 volts but may taste bad
i usually vape at 4 volts for my 1.8 ohm
and 4.8 for my 2.5 ohm

 

[Markus765]

I'm using a Spinner VV with Aspire BDC's with 2.1's @ 4amps, and Mini Protank 2's with 2.2's at 4 amps.

 

[BigEgo]

It's all about the current (amps) your battery puts out. Most ego-style batteries have an amp limit around 2.5 amps. Using Ohm's law, we can easily calculate a few things:

2 ohms @ 4v = 8 watts. This requires a 2 amp draw from the battery.

2.5 ohms @ 4.5v = 8.1 watts. This requires 1.8 amps from the battery.

3 ohms @ 5v requires = 8.3 watts. This requires 1.66 amps from the battery.


So, as you can see, even though the voltage is increasing, the power requirement is staying the same and the amperage required is actually decreasing as long as the resistance also increases. Thus, you can get longer battery life if you use higher voltage with higher resistance than you can by using that same voltage on lower resistance.

So, even though in the last example I have the battery at 5 volts, it still is using only using 1.66 amps which means the battery wont drain as quickly as it would at 2ohms and 4v.

Moral of the story: higher volts and/or higher wattage does NOT mean the battery will drain faster. It all depends on the resistance of the atomizer.

 

[LoganH]

Great info that I needed. I just started wrapping my own coils and this definitely helps.

 

[hesitantly]

It's kind of scary, but I'm almost starting to understand some of this.
Thanks for that cool chart!