Still trying to wrap my head around dual coil calculations...

[Ebertshay]

Hi all, so I think I'm begging to grasp dual coil config but still have a couple things I'm uncertain of. For the sake of ease let's use the example that I have a dual build that reads 1 ohm and a fresh battery at 4.2 volts.

1. Now, as I understand ( and please correct me if I'm wrong) I actually have 2 separate coils each rating at 2 ohms each?

2. Do I use the calculation for 1 ohm (17.64 watts) or 2 ohm (8.82 watts)? I asked this question before and was told that both are technically correct.. But how can they both be correct... Even if each are pumping out 8.82 and totaling 17.64, would that mean that I am really just using 8.82 and getting more vapor due to surface area? (And not actually getting the warmth and overall experience of 17.64 watt vape). Someone pointed me to a post about series resistance but it was a little over my head...

3. Wattage set aside, and the most important part, amperage (for safety reasons): since the battery is powering both coils, am I actually asking the battery for 4.2 amps? Or for 2.1 amps? I know my batteries continuos output could handle either in this hypothetical scenerio, but if I had built a lower ohm setup, then using my 18650s would be a no-go..

Thanks in advance everyone

 

[Credo]

4.2 Amps

When you add another coil in parallel, the resistance is reduced and the current goes up.

I.E. a pair of 2 Ohm coils would yield a build with 1 Ohm total resistance.
At 4.2v, you would get a little over 17.64 watts of total power.

The watts would be spread across the two coils however...approximately 8.82 watts per coil.

 

[Ebertshay]

4.2 Amps

When you add another coil in parallel, the resistance is reduced and the current goes up.

I.E. a pair of 2 Ohm coils would yield a build with 1 Ohm total resistance.
At 4.2v, you would get a little over 17.64 watts of total power.

The watts would be spread across the two coils however...approximately 8.82 watts per coil.

That makes sense, so even though it's still 17 ish watts total, would it be a different vape? (Like cooler or something)
I guess what I'm asking is how does the fact that it's spread out across the 2 coils affect the vape?

 

[Credo]

The general idea behind multiple coils is to have more surface area to produce more vapor.

If you have two coils working at temperatures barely hot enough to make vapor, you can still get twice as much vapor without running into wicking issues, scorched liquids, etc.

You could also make a longer single coil and get lots of surface area right? The thing with this approach is the coils will take a little longer to 'heat up'...hence 'lag time'.

Once you've coils hot enough to make vapor, the rest is about draw style, air flow, wicking that is right for that heat, and personal preferences on over all temperature.

 

[Ebertshay]

That makes sense! I'll think it over and let it all soak in haha. but I think I get it now. Thanks for your help!

 

[JD1]

1. Correct. You want the resistance down each leg to be as close to the same as possible so that each coil heats the same. When they are the same, it makes the math easy. Total resistance will be half the resistance of either leg.

2. You can use the calculation for 1 ohm (17.64 watts), or use the calculation for each leg (8.82) and add them together. You add because both legs are using 8.82 watts.

3. Amperage pull from your battery is 4.2 amps. There's 2.1 amps going down each leg for a total amp drain of 4.2 amps.

What isn't necessarily intuitive is that 4.2 volts is applied to both legs, and not divided down the two legs.

All you have to remember though, is that your resistance meter will give you total resistance (1 ohm in the example), then amperage can be calculated from the applied voltage number and the total resistance number.

Edit: I type too slow lol. Good answers above.