Need some sub ohm coil math. Help protect my life!

[xxbodkinxx]

Just got a setup which is right at .5 ohms. I want to make sure I'm not doing anything stupid regarding my batteries. They are the new AW imr 18650 2200mah batteries.

Here are the stats

Nominal Voltage : 3.7V
Capacity : 2200mAh
Lowest Discharge Voltage : 2.50V
Standard Charge : CC/CV ( max. charging rate 2.2A )
Cycle Life : > 500 cycles
Max. continuous discharge rate : 20A
Operating Discharge Temperature : -10 - 60 Degree Celsius

Am I ok?

 

[coaldriller]

Yes sir you are


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[Sloth Tonight]

Golden, so golden. You're well within your batteries capabilities at .5 ohms. Do you have a smart phone? Download the Vapors Toolbox app if so. it's free and you can calculate amperage in a matter of seconds on the fly.

 

[coaldriller]

35w. at 8.4amps


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[Sloth Tonight]

And to be specific your battery is 20 amps. Your draw at .5 ohms is around 8.40 amps. I run the 2200s on my .4 builds and that's only drawing 10.50 amps.

 

[xxbodkinxx]

Golden, so golden. You're well within your batteries capabilities at .5 ohms. Do you have a smart phone? Download the Vapors Toolbox app if so. it's free and you can calculate amperage in a matter of seconds on the fly.

Dont have android and that app isnt available. whats the formula to tell you what you can run etc? Also as the battery drains it only gets safer right? Sorry for the noob questions.

 

[xxbodkinxx]

 

[Sloth Tonight]

Amps = voltage divided by resistance. So in your case, it's:

4.2 / .5 = 8.4

Always calculate based upon the highest possible output of your battery, ie 4.2 volts when it's fresh.

As your battery drains you draw less amperage. If your battery is at 4 volts, it's
4 / .5 = 8 amps

So I'll let someone else answer if it gets safer but basically I think so. Just don't vape it too low. It hurts the life cycle of a battery to go below 3.7 volts. And batteries drain faster with lower resistance so you'll need to check it periodically to get a feel for when your batteries need swapped.

 

[Papa_Lazarou]

Yep - always do the math based on the max voltage, 4.2V in the case of a single bat in a reo.

As for safety margin (and you should account for some), folks use anything between 20-100%. So, do the math sloth showed you above and add the safety margin. Then compare that to your bat's continuous amp rating. In the case of your AW 2200's you have >100% safety margin, so you're good.

Amps are pretty much amps, so as the bat drains, the current drawn diminishes with it and you get farther and farther away from the bat's limit (i.e., less risky). Don't vape below about 3.6V just to be safe in terms of bat cell health, but you should feel a real drop off in vape quality below about 3.8V.

Here's a link to a coil parameter tool that helps you do the math involved...

Coil wrapping | Steam Engine | free vaping calculators

 

[muzichead]

Ohm's Law Calculator

 

[xxbodkinxx]

Sounds good guys. Thanks!

 

[JetMac]

You might not want to discharge your batteries down to 2.5, full charge on your battery is 4.2 and most people discharge them down to 3.7 and then charge them.


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[zeronic2013]

I use the OHM's Law app on my iPhone for quick calcs because I don't trust my math [emoji51]


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