Variable Wattage systems.. Basic Understandings

FattyMcChubChub;8767633 said:

It's really confusing at first, I had to remember back to my highschool electronics class to start understanding everything.

This thred can help put you on the right track.
http://www.e-cigarette-forum.com/forum/new-members-forum/383359-question-volts-watts-ohms.html

This should help as well. Ohm's Law Calculator
(Enter in any two known values to get your answer.)

If you are playing around with atomizers that have different resistance ratings on a fixed voltage/wattage system, you'll have a frustrating time getting them to work just right. A burnt taste could be a dry wick. At the same time the ohms could be too low and voltage is too high. If there's no flavor and it's a really cool vape, the ohms may be too high and the voltage too low.

It can get pretty technical but the basics for ohms ratings are pretty simple. Your average available resistances are usually 1.8, 2.0, 2.5, 2.8, and 3.0 ohms. Finding the volts/watts for each of them is widely dependent on personal preference too.

A good starting basis:
1.8 ohms - 3.7 volts
2.0 ohms - 4.0 volts
2.5 ohms - 4.4-4.5 volts
2.8 ohms - 4.7-5.0 volts
3.0 ohms - 5.0-5.5 volts

Hope this helps get you started.

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Disconnect;8777318 said:

VV and VW do basically the same thing - change the voltage according to your setting. The only problem is, your goal isn't a particular voltage - you are looking for a wattage. (Even if you don't know it ) 4V on one head is going to be different (between a little and a lot) on a different head. (I've pulled "2.8" out of the box and gotten anywhere from 2.1 to 3.5. Usually its not that bad, but..)

The V/W devices go a step farther than V/V and measure the resistance for you, so that you can just say "I love 7W" (or 5W or 10W or..) and it will automatically set the correct voltage. It also adds a lot of convenience when switching between LR/SR/HR since you don't risk blowing up the atty (or your face.. 11W cinnamon HURTS) by having the voltage too high..

Here is a nice wattage cheat sheet btw:

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Eddie deGrouch;8779527 said:

This helped me, also. Let me see if I have it straight using crayons and poor car analogies...

For this example:
Voltage = gas pedal. 3v to 6v (3000 to 6000 rpm)
Atty ohms = gear. The higher the Ohms the LOWER the gear. 3 ohm = 1st gear, 2.5 ohm = 2nd gear, 2 ohm = 3rd gear and 1.5 ohm = 4th gear.
Atty refers to all types of heating elements whether carto, atty, etc.

I want to go 65 mph with this juice...

*Pause while mail person delivers e-stuff to me. YAY*

With a regular battery, let's say 3.7v, I have a motor that goes 3700 rpm ONLY so I need to match it with 2nd gear or 2 ohm to get 57 mph. In the ballpark and usable but not perfect.
You have to match the carto or atty ohms to get in the ballpark of watts or heat for the juice. Different juices will want differing heat so you have to have a selection of carts or batteries.

With a Variable Voltage (VV) mod you now have 3000 to 6000 rpm to play with. I can load whatever atty I have and dial in the speed I want within reaon.
You can adjust the voltage to the atty ohms to get the proper WATTS or heat for your juice.

With a Variable Wattage (VW) mod you have cruise control. Set it for 65 mph or 5 watts and it will match the rpm (voltage) to the gear you have installed (ohms) automatically.

Have I come close?

Ed

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Disconnect;8787947 said:

No math needed with the charts, unless you go to dual-coil.

Kinda OT, but let me save everyone the insane amounts of searching I had to do. I found this thread that gives good info on dual-coil cartos/etc.

The TL;DR version is that you double the target wattage for a dual coil head.

I'll stick with 1.5ohm since that is the most common.

A 1.5ohm dual coil is actually 2 coils at 3ohms each. So to find your voltage, you use 3 ohms on the left of the chart to get the watts you want, then read the voltage off the top (same as anything else.) BUT.. this is where it gets strange. The actual wattage that it will use is according to the 1.5 ohm list for that voltage. (2x the wattage you are 'aiming' for.)

Example: to get an equivalent of 8 watts on a DC 1.5ohm carto, you read 3.0 ohms over to 8W (between 4.75 and 5V.) On a VV device, you set that and if it can handle the load, you are done. On a VW device, slide up to 1.5ohm and the wattage is actually around 16W. (Double the wattage.)

I wish I'd found that info the other day, since it turns out I can't (reasonably) use all my DC cartos on my evic. (11W limit means 5.5W per coil on DC.. A little low for most of my juices.)

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AttyPops;8788653 said:

The more common issues are:

A) Amp ratings for a device. Make sure you can get enough amps (This is important only if you use dual-coil stuff....and many NEVER do...and hate em.)
B) Device construction and how well it holds up
C) Having a multimeter to check actual ohms if the device doesn't tell you (and a MM is handy for lots of stuff around the house).
D) Juice viscosity. Too thick and it won't wick and it burns and then people get confused and think it's a voltage issue or something.

I can make an e-cig with some batteries, gusto, and 2 wires. But....it helps to know the ohms/voltage theory to get into the ballpark. VV is fine. I"m an e-cig old fart. "I remember the days...." we didn't have VV let alone VW. lol.

EDIT:

Repeat this to yourself:
"Heat = voltage squared divided by ohms...Heat = voltage squared divided by ohms...Heat = voltage squared divided by ohms...Heat = voltage squared divided by ohms...Heat = voltage squared divided by ohms"
Then you don't have to carry around a chart or some such. That's the watts calc. If you have a device that shows you the watts....then you can avoid the math. Meh.

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