Why don’t high watt mods use high resistance coils?

[Doglips]

This is along the lines of the post by nemoishouse ...I just can not get my brain wrapped around the mega watt arms race....but what confuses me is the Ohms. Back in the stone age of ego’s the small battery could only power 1.6 1.8 Ohm stuff...then we got more power..vv vw and and we jumped up to 2.6 ??(Been a long time so not exactly sure what it was)....I seem to remember 5 ohm coils....I could be wrong.

But to get to the point. In my mind more power would be used to power larger coils...so higher resistance...like pulling a trailer with a car..small trailer...pick up larger trailer...semi truck huge trailer.

That’s what is confusing me, it just seems like some 150 Watt beast would need high resistance...like inches of wire long coils 20 30 or so ohms....instead it’s the exact opposite, Hugh mods with sub ohm coils and small ego mods with lets just say 2x the resistance (.8 sub ohm vs. 1.6 ohm ego).

So can someone explain to me why the mods get more power...but the resistance gets smaller...instead of larger as well.


Also can someone explain how the keger turbo..using 2 1.6 ohm heads =.08 ohms? My brain goes 1.6+1.6+=3.2.

Thanks everyone..

 

[rondasherrill]

These high wattage mods are still using massive coils... Just people are using multicoil setups with thicker guage wire, that require more power to get the same heat out of them.

2 coils in series would be added, as in 1.6+1.6=3.2, BUT these multicoil setups have the coils in parallel, so...
2 coils in parallel is Total = R1*R2/(R1 + R2), so Total = (1.6*1.6)/(1.6 + 1.6) = 0.8

 

[bussdriver]

Using ohms law:
a 1 ohm coil at 4 volts would draw 4 amps. The power generated would be 16 watts.
With a 2 ohm coil at 4 volts, 2 amps flows. The power generated would be 8 watts.
To generate 16 watts in a 2 ohm coil, the voltage required would be 5.66 volts.
To generate 16 watts in a 4 ohm coil, the voltage required would be 8 volts.
To generate 30 watts in a 4 ohm coil, the voltage required would be 10.95 volts.
To generate 30 watts in a .2 ohm coil, the voltage required would be 2.45 volts.

As you can see, you can generate much more power at a given voltage if you simply lower the resistance. Using higher resistance coils certainly is possible, but the first thing that would be needed would be "battery stacking" to get the necessary voltage to drive the higher resistances to higher power outputs. Stacking of batteries used to be more common than it is now, with all the safety concerns.

Most mods use "buck converters". These devices will lower the voltage, but not raise it. It's easy to handle large currents with these. To go the other way and raise the voltage, you use a "boost converter". Only problem with these, is that they are larger and not as efficient. It's also more difficult to make them handle large currents. This inability to handle these larger currents is why mods don't "handle it all".

Some newer mods try to do both, but they don't really do it well. Another poster in another thread mentioned he saw stacking of batteries in one mod new he saw. This of course would be done to increase the voltage. But, this is not recommended in any high current application, making the device dangerous for sub-ohming.

It's all a tradeoff. You simply buy the mod to fit your vaping needs.

 

[imsoenthused]

It's just voltage considerations. The max voltage on even the newer high watt mods tends to be fairly low, so hitting those wattages is going to require fairly low ohms.