Formula for finding how much power ( watts ) you can use for 1, 2, 3, 4 Batteries etc

[mj79]

Im looking for some new batteries for a 4 battery mod I am looking to buy ( not sure which one yet ) But have really been looking at the HG2s from LG.
I currently have sony vtc5 in my alien , and have been pretty happy so far, but just could use a bit more battery life, as I seem to come about an hour or so short of a full day . Knowing pretty close what the battery meter on the Alien reads, I tend to try to charge them when they get around 3.5v

My question is, Whats the math to figure out the "safe" limits to your batteries? Say , if I were to have 2 lg hg2 in my Alien, what is the highest wattage I could go safely? Right around 140-150?

Even Looking into the LG HB2/4 , which I believe Mooch rated at 30A , 2 of them technically would not even be enough to push my Alien to 200 watts? Or that's what I read on here somewhere.

 

[DaveP]

Wattage variables change significantly when the mod actually generates power to a coil. You probably know that Ohm's law goes out the window in terms of amperage drawn from batteries in that situation.

Here's a thread you might find interesting. It should answer your question.
Calculating battery current draw for a regulated mod | E-Cigarette Forum

The mod can vary voltage up and down to create the most efficient power delivery algorithm for a given coil resistance and power selection, while the battery voltage feeding the mod's electronics is stable. There's little correlation between the two circuits in operation. The mod's circuitry takes the brunt of the amp load to the coil. The batteries just supply current to drive the mod's electronics.

I didn't see the Smok Alien 200W in Steam Engine, but you can play with the variables for a similar mod to see how it all works at high wattage.

Mod range | Steam Engine | free vaping calculators

 

[mj79]

thank you!

Yea I was just wondering on a more basic level, of if I have 2 20A 18650s, @ .5 ohm what is the "safe zone" power level, vs 2 30A 18650s on the same setup.. But I'll read through those links for sure

Thanks again!

 

[mj79]

Ok so If I got this right...

The alien is 220w ( theoretically )

which is 110w per battery.

discharge rate of most batteries are based of the 3.2V avg cutoff

So In order to run 220 watts to the alien, It would be

110/3.2 , which equals 34.38correct? Which would mean I would need ( if they were available ) 2 - 35 amp 18650s?


On the other hand by just doing a little more math, with my current 20A VTC5 batteries , the max I should be running is about 130 watts? ( 20.3 amps )


AS well as if I were to get some HB2 30A batteries , they should be good to 192 watts?

I'll post below why I was so confused, when I saw Moochs way ( although I obviously know his way is correct.. But I saw this in the forum, and not only was the math wrong, it was a different way of doing it....

 

[mj79]

When asking for batteries for the alien this was posted by a member

Depends on how high you'll be vaping.
Watts+10%(for device inefficiency)/cutoff voltage for mod (usually 3.2v)=amps. In series mods (like most variable wattage ones out there) you mulitply the cutoff voltage by the number of batteries.

eg: say you want to vape your Alien at 100w: 100+10% for inefficiency (110w)/3.2v*2batteries=6.4v so 110/6.4=roughly 18.2a.

The VTC5 is a 20a cell, so you'll reach it's constant current limit at 128w. if you don't plant on going over 110w, you should be just fine with them.

I'm sure someone with more knowledge can explain further in detail.


Then I saw this while looking for a battery for the GX350.. Taking into account the HG2 for example

He said the HG2 x 4 is only good to 207 wats, but I got a touch over 230 .. 230/4/3.2=17.96A , as Mooch rated the hg2 @ 18 amps I believe

Make it simple for you
Upto to 230watts on the GX350 = 4 X Samsung 30Q 3000mah
Upto 219watts on the GX350 = 4 X Sony VTC6 3000mah
Upto 207watts on the GX350 = 4 X LG HG2 3000mah
Upto 288watts on the GX350 = 4 X Sony VTC5A 2500mah 25amp CDR
Upto 350watts on the GX350 = 4 X LG HB2, HB4, HB6 1500mah 30amp CDR (No other 18650 battery on the market is higher in Continuous Amp Discharge Rate than these 3 batteries on the market, anyone say 35 or 40amps is a re-wrap of a battery LG, Samsung, Sony, or Panasonic/Sanyo did not pass A Bin specs and are showing pulse discharge rate, not the CDR)

 

[KenD]

Im looking for some new batteries for a 4 battery mod I am looking to buy ( not sure which one yet ) But have really been looking at the HG2s from LG.
I currently have sony vtc5 in my alien , and have been pretty happy so far, but just could use a bit more battery life, as I seem to come about an hour or so short of a full day . Knowing pretty close what the battery meter on the Alien reads, I tend to try to charge them when they get around 3.5v

My question is, Whats the math to figure out the "safe" limits to your batteries? Say , if I were to have 2 lg hg2 in my Alien, what is the highest wattage I could go safely? Right around 140-150?

Even Looking into the LG HB2/4 , which I believe Mooch rated at 30A , 2 of them technically would not even be enough to push my Alien to 200 watts? Or that's what I read on here somewhere.

The Alien has a low cutoff voltage so with the LG hg2s, or Sony vtc5s, you'll exceed the cdr at around 105w. However, if you remove the batteries at 3.5v you're good up to about 125w. With the Sony vtc5a (not vtc5) you'd be good up to about 130w (160w if recharging at 3.5v), and with the LG hb2/4/6 up to about 160w (190w if recharging at 3.5v). That's with keeping the load within the cdr of the batteries and assuming a 90% mod efficiency.

Sent from my K6000 Pro using Tapatalk

 

[mj79]

The Alien has a low cutoff voltage so with the LG hg2s, or Sony vtc5s, you'll exceed the cdr at around 105w. However, if you remove the batteries at 3.5v you're good up to about 125w. With the Sony vtc5a (not vtc5) you'd be good up to about 130w (160w if recharging at 3.5v), and with the LG hb2/4/6 up to about 160w (190w if recharging at 3.5v). That's with keeping the load within the cdr of the batteries and assuming a 90% mod efficiency.

Sent from my K6000 Pro using Tapatalk

ok I'll ask the stupid question. Why do most sites sat to divide by 3.2 when the alien goes lower , I'm guessing 3.0?

 

[KenD]

ok I'll ask the stupid question. Why do most sites sat to divide by 3.2 when the alien goes lower , I'm guessing 3.0?

Most mods cut off at around 3.2-3.3v, that's why using 3.2v in amp draw calculations is recommended. The Alien cuts off at around 2.8-2.9v, although there are reports (just a single person though) of some having a higher cutoff. If you have a digital multimeter or a charger that shows the voltage you could try using the Alien until it cuts off and check the voltage at that point.

Sent from my K6000 Pro using Tapatalk

 

[DaveP]

Smok Alien battery thread here discusses various batteries for the Alien.

Is the SONY VTC5 18650 batteries good for the SMOK Alien 220w?

 

[The.Drifter]

Somebody posted this chart awhile back, it's a pretty handy visual reference.