Question About Voltage

[jolly_st_nic]

Hi all. I have a sigelei 75 watt and it takes a single battery. I'm using a 3.7 volt 2500 mAh 18650 battery and running a 0.4 ohm tank at 47 watts. When I fire the mod, the voltage reads 4.38V. Question: is the battery really delivering 4.38V to the tank, or is it just delivering the rated voltage once I get above 3.7V using the power setting? I like the amount of vapor, flavor, etc. but I would still like to know. If I turn down the watts setting to where the mod reads ~3.7V, there is actually a very noticeable decrease in flavor/vapor, so I'm not getting how exactly this works.

 

[SupplyDaddy]

That voltage is about right for a .4 ohm coil at 47 watts.
You battery, fully charged is 4.2ish volts. Your device is a buck-boost system, meaning it will boost your voltage to that needed via the chip system, or it will buck your voltage down via the chip system.
Your battery will output to the chip system what it has (4.2v and down) and the chip system will convert it to the required voltage for use.

 

[jolly_st_nic]

Ah, ok. So the voltage reading on the device is the accurate number of volts being fed to the atomizer by the chip, which can be higher than the volts being fed to the chip by the battery. So that means if I increased the wattage to 50 or 60 watts, I'd see an increase in volts even higher above the rated battery voltage, and flavor/vapor would increase because the chip has the ability to up the voltage. Got it. Thanks for your help.

 

[sonicbomb]

Firstly what battery are you using, as this is actually the important question.

On a regulated mod the coil resistance is unimportant. The regulator chip delivers the wattage you set to the atomizer, this is the voltage value you are seeing, it doesn't bear any relation to the battery voltage, and you don't need to worry about it. The regulator is able to 'step up' the voltage from what is available in the battery.
A fully charged 18650 is 4.2 volts, 3.7 volts is the nominal value where it will remain around for the longest as it discharges, again you don't need to worry about this.

A regulated mod will draw the smallest amount of amps from the battery when it is fully charged at 4.2v and the most when it is discharged at 3.2v. So if you ran the mod at 75 watts you would be pulling 20 amps initially then 26 amps discharged. You need to make sure your battery is capable of safely delivering this or use less wattage. A general rule of thumb for a single 20 amp CDR battery is 60 watts max.

You can model all this in steam-engine.

 

[jolly_st_nic]

sonicbomb, thanks for the info. I don't chase clouds - just a smoker and I like a tobacco/ashtray flavor out of a cigarette-sized exhale. I always stay on the small end of recommended watts. That's a good rule about the 60 watts. When I was a kid, I built simple circuitry for fun and managed to get some op-amps and batteries scorching hot with my experiments. I learned a respect for electricity, even those little Energizer 9 volts, so I won't be getting too out of hand with this mod.

 

[somdcomputerguy]

I learned a respect for electricity, even those little Energizer 9 volts, so I won't be getting too out of hand with this mod.

There are old electricians. There are bold electricians. There are no old and bold electricians.

 

[sonicbomb]

So what battery are you using?

 

[jolly_st_nic]

I'm using a 3.7 volt 2500 mAh 18650 battery

sonicbomb, or do you mean what brand of battery? I have no idea. It is packaged or repackaged with a white label listing the specs. Maybe the name of the brand is under the label, but I haven't checked.

 

[jolly_st_nic]

Oh, and they're Li-ion. The box they came in is generic with no brand named, but it does say that. I'm using a 0.6 ohm coil at the moment at 35 watts (drawing ~7.5 amps). I think I'm good unless it's a super low-quality one, which it always could be, but nothing is perfectly safe.

 

[sonicbomb]

As long as it capable of safely supplying the amp you demand of it you are golden. However if you don't know what it's capable of...
Peel off the white label, and take a picture showing the numbers underneath and we should be able to get it identified.

 

[jolly_st_nic]

Thanks for helping me out! In case you can't see the info in the picture, it says:

INR18650-25R
SAMSUNG SDI
5 2G43

According to the entry for my battery at this link, I should be good. Continuous discharge is rated at 20A, max discharge is 35A, and it's safe to run down to 0.2 ohms. I got four of these at a very busy vape shop here in town, and it would surprise me if they were selling low quality to everyone.

Battery mAh & C Rating = amp Calculator

 

[sonicbomb]

Cool, the 25-R is a good 20 amp battery
Samsung Green 25R (25R5) 20A 2500mAh 18650 Bench Retest Results...a great 20A battery