Batteries and Temperature Control

[cvigti]

Hi everybody!

I ordered a VTC mini. With it, I ordered two EFEST IMR 18650 3500MAH - 20A batteries. After searching and reading alot I found that they are 10A continuous and 20A pulse discharge.
I plan to vape with my nautilus with 1.6ohm bvc coils at 11w. But I did order an extra ni200 coil to try TC. (aspire now has this coils for the triton mini and compatible with the nautilus, the nautilus is a beast for us no-hassle mouth to lungers). I was wondering if these batteries would suffice for TC on those 0.15 ni200 coils or at what maximum wattage should I set the VTC, because of the batteries. I'm not sure but I think they are continuous 10A and so I could probably go to 15w max on that coil...a bit anemic maybe? I love capacity, that's why I chose those efest, but they are new on the market and all I know is hearsay. On the other hand, some people have told me that that is not how TC works and that I could set my vtc to 75w if I wanted with this batteries because the peak discharge is miliseconds and the vtc itself would protect me from anything else. (not convinced, of course!). What battery do you recommend that I use on my vtc mini?

In short, how does Temperature Control affect a battery when it comes to Amperage? If a battery has a continuous 10A rating and you have a standard sub-ohm coil at 0.15ohms(kanthal) you shouldn't go past 15W (AFAIK), does the same apply when the coil is a Ni200 coil 0.15ohms and is being used on a TC mod? Or in that case you can ramp up the wattage?

edit: Since my order hasn't been shipped yet I asked the store to change those Efest to Samsung's 25R (blue, no green available). The question still remains, as does the curiosity

 

[Boden]

10A • 3.2V = 32W

10A is the battery

3.2V is the mods low vlotage cut off.

So 32W is as high as you would set the wattage to never exceed 10A.

 

[Topwater Elvis]

I am short on time right now but, YES change your order to the samsung 25r.

 

[sonicbomb]

Efest batteries are garbage, don't buy them under any circumstances.

 

[cvigti]

10A • 3.2V = 32W

10A is the battery

3.2V is the mods low vlotage cut off voltage.

So 32W is as high as you would set the wattage to never exceed 10A.

One question. So if I set my device to 32W and the coil I have is 0.15ohm ni200 wouldn't that put the amps at 14/15 being pulled from the battery?

And on that note/logic, wouldn't it mean you can only use like 64W on the batteries that have a 20A rating? And with a minimum coil of 0.16ohms? Or does the ohms law not apply in TC?

 

[coilburner]

Not only are they no where near 20 amp batteries but Im almost positive there not 3500mAh either.

 

[cvigti]

Not only are they no where near 20 amp batteries but Im almost positive there not 3500mAh either.

Yes I know...they are 10A continuous, 20A pulse. As for the 3500mah I have my doubts also...

 

[Boden]

One question. So if I set my device to 32W and the coil I have is 0.15ohm ni200 wouldn't that put the amps at 14/15 being pulled from the battery?

No, the resistance of the coil is irrelevant with regulated mods.

 

[Boden]

There is no such thing as a pulse rating for ecig use.

 

[cvigti]

So in TC if I set my VTC mini to 32W using those efest there is no problem (10A rating)? Or, if I use the 25R (20A I think) I can't set at 75W, only 64W? So is that like the max wattage for single battery mods in TC, no matter the resistance? Or, for the sake of arguing, if you find a 30A battery, in a single battery mod, the limit should be 96W? Is that why you can put like 200W in a releaux in TC for example? Because the voltage is divided by all three batteries?

 

[coilburner]

There is no such thing as a pulse rating for ecig use.

Yes, I was just reading mooches blog and he says that pulse ratings are completely useless. I for one never even bothered considering pulse ratings.

 

[Boden]

So in TC if I set my VTC mini to 32W using those efest there is no problem (10A rating)? Or, if I use the 25R (20A I think) I can't set at 75W, only 64W? So is that like the max wattage for single battery mods in TC, no matter the resistance?

The math is simple.

Battery amps • mod low voltage cut off = max Watts

Using VTC mini

20A • 3.2V = 64W

 

[cvigti]

The math is simple.

Battery amps • mod low voltage cut off = max Watts

Using VTC mini

20A • 3.2V = 64W

Is the same valid for what I added in edit? If so you just gave me a piece of information I hadn't seen before anywhere and I thank you!

edit: 3*3.2v= 9.6v
20*9.6v= 192W
Is that how it works?

Is this only for TC because resistance doesn't matter or for every type of coil? I always counted on ohms law and never thought about it that way...

 

[Boden]

Or, for the sake of arguing, if you find a 30A battery, in a single battery mod, the limit should be 96W? Is that why you can put like 200W in a releaux in TC for example? Because the voltage is divided by all three batteries?

Assuming a 3.2V cut off.

30A • 3.2V = 96W


Since I don't know the low voltage cut off in the Reuleaux I'll make one up. 3.4V per cell sounds good.

Lets use 20A cells

3.4V • 3 cells = 10.2V

10.2V • 20A = 204W

 

[cvigti]

I never thought of it that way. That simplifies thing so much. So all I need to know is the device cut off and the rating of the battery (and number of batteries) and I get the maximum wattage for safety. :O

 

[Boden]

edit: 3*3.2v= 9.6v
20*9.6v= 192W
Is that how it works?

Yes

Is this only for TC because resistance doesn't matter or for every type of coil? I always counted on ohms law and never thought about it that way...

It doesn't matter what the coil material is.

 

[cvigti]

Yes



It doesn't matter what the coil material is.

Thanks Boden. In my 3,5 years of vaping I've just used a provari v2 and an eleaf 50w (among cigalikes and egos) and always relied on ohms law and the amp limit set by the manufacturers to calculate. I was always stuck at the 2.5A limit of the provari or the 4/4.5A limit of the istick 50w...So I never payed attention to the batteries themselves until now when buying the VTC and using sub-ohm, because of safety. That was probably a well known fact among the mech guys but I never dwelve into that...

Thanx once again and I am baffled as why I have never seen this information before...I really thought that with a battery at 10A rating I could only go to 15w with a 0.15 coil... ohms law...at 32W it gives me 15A.

edit: can you give me a link to some of this information? Or at least how you'd call it for me to research further? Like ohms law, easy to find, but what do you call this "method"?

 

[Boden]

Thanks Boden. In my 3,5 years of vaping I've just used a provari v2 and an eleaf 50w (among cigalikes and egos) and always relied on ohms law and the amp limit set by the manufacturers to calculate. I was always stuck at the 2.5A limit of the provari or the 4/4.5A limit of the istick 50w...So I never payed attention to the batteries themselves until now when buying the VTC and using sub-ohm, because of safety. That was probably a well known fact among the mech guys but I never dwelve into that...

Thanx once again and I am baffled as why I have never seen this information before...I really thought that with a battery at 10A rating I could only go to 15w with a 0.15 coil... ohms law...at 32W it gives me 15A.

edit: can you give me a link to some of this information? Or at least how you'd call it for me to research further? Like ohms law, easy to find, but what do you call this "method"?

In a mech the battery sees the resistance
Ohm's Law

In a regulated mod the battery only sees the chip-set and it's demands. When you tell the chip-set you want the coil to make 30W of heat it looks at the resistance and calculates the voltage it needs to apply. Then It draws the amount of power it needs to accomplish this.

Since amp draw is highest at low cell voltage we use the low voltage cut off.
How to convert amps to watts (W)

 

[cvigti]

Just leaving it here for others

Ok...so basically it's I = P/V, Current = Power/Voltage.

A thread I found on reddit:

"I saw a guy earlier who was talking about his build on a regulated mod. He said "I am running 0.3Ω at 80 watts. This equals 16 amps, so I am well within the safe limits of my 20 amp battery." Well, he committed the cardinal sin of using the output voltage in his calculation (or using Power and atomizer resistance to calculate current -- neither are correct). Let's do his calculation properly. If his battery is fully charged (around 4v) and he is running at 80 watts, then:

I = P/V

80/4 = 20 amps.

In reality he is pulling 20 amps on a full charge, not 16 as he thinks. But that's not all. Since the battery voltage drops during use, the regulator will have to increase the amperage drawn to keep him at 80 watts. So, let's say his battery is near dead and is at 3.2v.

80/3.2 = 25 amps

Now, since most batteries are 20 amps continuous, we might be getting into some danger territory (possibly). Meanwhile this guy is vaping happy thinking he is still only pulling 16 amps from the battery."

So that's why Boden was talking about the 3,2v...it depends on the cuttof since a mech can go lower than that...but mechs are different because there is no regulator to keep the power constant, I guess that's where the ohms law enters.

More info:
PSA: You Don't Calculate Current Draw on Regulated Mods Like You Do on Mech Mods • /r/electronic_cigarette

 

[cvigti]

In a mech the battery sees the resistance
Ohm's Law

In a regulated mod the battery only sees the chip-set and it's demands. When you tell the chip-set you want the coil to make 30W of heat it looks at the resistance and calculates the voltage it needs to apply. Then It draws the amount of power it needs to accomplish this.

Since amp draw is highest at low cell voltage we use the low voltage cut off.
How to convert amps to watts (W)

I guess in my mind I always thought that a regulated mod used its buck boost or whatever it's called to increase the voltage, and not the amperage. That was my mistake. I always thought that if I set the provari at 5v it would increase somehow the voltage given by the battery, never ocurred to me it was the amperage. I was just happy it gave me that voltage until the battery died. Now I understand it better hehe
I also thought like in a mech, where a full charge battery (4.2v max) would pull more amps than a depleted one (3.2 for instance). In regulated it's the opposite.