Box Mod Voltmeter Readings.

[augustkk]

Hello, I bought my first unregulated box mod last week It has a voltmeter and I'm trying to understand the readings.

It takes three 26650 batteries in parallel.

When the batteries are at full charge with no atomizer it reads about 4.10.

When I put on a build of .16 ohm it reads about 3.50

and when I put on a build of .08 ohm it reads about 2.75

Is this normal?

 

[Robert Cromwell]

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Hello, I bought my first unregulated box mod last week It has a voltmeter and I'm trying to understand the readings.

It takes three 26650 batteries in parallel.

When the batteries are at full charge with no atomizer it reads about 4.10.

When I put on a build of .16 ohm it reads about 3.50

and when I put on a build of .08 ohm it reads about 2.75

Is this normal?

Considering the content "normal" is a subjective thing

but yes the voltage will drop because of the higher current requirements of the lower resistance coils.

 

[augustkk]

Does this mean that the mod is providing less power to the lower resistance coils?

 

[Robert Cromwell]

Nope providing more. You really need to understand Ohms law and battery safety better if you are going to vape with the type of high powered gear you are using.

Watch some videos on youtube on ohms law and battery safety.

 

[augustkk]

Will do, thanks for the advice.

I only take 1 puff at a time to keep the thing cool.

 

[Rsunderl]

Assuming you have a really good, accurate ohm meter to check your build (you do, don't you? ), a .08 ohm coil will draw 52.5 amps from your 3 batteries. If your meter is off by even .01 ohms, and the coil is really .07 ohms, you will be drawing 60 amps.

You didn't mention which batteries, so I'm guessing that they are rated at 20 amps continuous. (You should always use the continuous rating when calculating for safety.) That leaves you only 12.5% of head room (again, assuming the build is really 0.08 ohms) for a safety margin. As your batteries age, the CDR will get lower, removing some of that safety margin.

Always keep those three batteries together, charge them together and rotate their positions when putting them back in your mod.

Taking one puf at a time to keeps things cool is probably a good idea, but isn't the total picture when it comes to battery safety.

Check out Baditudes blog post on battery/battery safety:

Battery Basics for Mods: IMR or Protected ICR?
- choose the safest and right battery for your applications here. Includes a list of name brand, high-drain, safe-chemistry batteries with mAh & amp ratings in 18350, 18490/18500, and 18650 sizes.

Hope it helps and Happy (and safe) Vaping!

 

[augustkk]

I'm using 3 MXJO IMR 26650's heres the specs:

-Capacity:3500mAh
-Nominal Voltage : 3.7V
-Max. Continuous Discharge Current :35A
-Max. Pulse Discharge Current : 60A
-Dimensions : 65*26MM (+/-0.05)mm
-Operating Discharge Temperature : -10 to 60 Degrees Celsius
-Standard Charge : CC/CV
-Cycle Life : > 500 cycles

I do charge them together and rotate them, I have them marked, I know that much.
And yes I have an ohm meter.

Are these batteries suitable for my application?

I,ve been sub-ohming for a couple years on regular 18650 mods without a problem, mostly at around .2. I build good coils without shorts.

Everything seems stable with the box mod in question, but I'll take you guy's advice and do some good research. Not only do I want to keep my mod, but my safety as well. That's a lot of battery I'm sticking in my face.

 

[Robert Cromwell]

Enjoy vaping but above all be safe.

 

[Rsunderl]

With those batteries, I'd say you should be ok. you might want to message @Baditude and get his opinion. He's the battery expert here on ECF.

 

[WhiskeyTango]

What mod takes three 26650s? That thing must be pretty big.