new to sub ohm need battery advice

[tangerine3]

Hello I am getting a Smoant Battlestar 200w with a uwell crown iii tank that uses .25 (80-90W) and .5 (70-80W) coil heads. When I used this calculator

https://vapecalc.com/

it says at .25ohm with 90 watts it says 18.97amps and at .5 at 80 watts it says 12.65amps. So it seems that using the .5 at max watts i'd be ok with a 20A but for the .25ohm at 90 watts I am getting close to the 20A limit. My question is 18.97amps to close to pushing the limits for use with a 20A battery or should I get a 25A or 30A battery just to be safe.

According to this table I found there are not that many true 25-30A batteries out there. So wondering if 20A would be safe.

https://www.e-cigarette-forum.com/forum/attachments/img_5441-jpg.658875/

Although i do see some LG HB2,4,6 that are 30A but only 1500mah, the battlestar takes two 18650 batteries so if I got those 1500s would that mean I would have 3000mah total for 30 hours of battery time???
Thank you.


Thank you.

 

[IMFire3605]

With a regulated mod, unlike a mechanical mod with no control board, is that a regulated mod amp pull is decided by 3 factors, mainly watts set and charge level of the batteries (lower the charge the higher the amp pull to sustain the needed voltage), and lastly the efficiency of the regulation control board or PCB of the mod, resistance only comes into play of what the PCB is programmed to handle and operate (0.1 to 3.0ohm for example) in as well as figure out voltage needed to reach set watts, after those, resistance is meaningless on a regulated mod.

(Watts Set/Lowest Voltage)/Mod Efficiency=Maximum Amps <-- Regulated Mod Formula

Where a Mechanical/Unregulated the formula is this
Highest Voltage generally Fresh Charge/Resistance or your Ohms=Maximum Amps <-- Most your Ohms Law Calculators use this method, but can be set to do otherwise to use Watts and voltage it is more accurate to use the above mentioned formula

Being the Battlestar is a dual battery series, we gain voltage x number of batteries, same mah and same cdr of a single battery, thus a voltage operating range on a single battery is 3.2v to 4.2v per battery, the Battlestar gives us a range of 6.4v to 8.4v, without knowing the specs of the PCB I am assuming the PCB uses 10% of power to function leaving 90% efficiently being supplied for actual vaping

90watts/6.4v lowest/90%=15.625amps, to reach close to the 18.97amps
90/5.3/90%=18.8679amps (5.3/2=2.65v per battery which is getting dangerous, we suggest 3.0v lowest because below 2.5v the electrolyte in the in the battery cold begin to dissolve the copper inside and cause micro-shorts potentially, and damaging the battery beyond recovery.)

Even at almost 19amps, any 20amp battery will suffice as you will not be fully energized in charge level once the amp draw reaches that point, unlike a mechanical at fresh charge full amp or over amp pull and generally not vaping at that amp pull for long as the mod soon shuts down or kicks check battery errors and refuse to fire.

At full charge as an example
90watts/8.4v fresh charge/90%=11.9048amps

You are plenty safe using any of the good 20amp CDR batteries, simple enough math, just need the 3 variables and a calculator which all current phones and media devices running Android or iOS should have (Smart Phone, iPad, iPod, etc).

 

[tangerine3]

oh boy, k i understand partially. tell me if i have this right for the battlestar that is a 200w two batt regulated device. If just for the sake of seeing if I can figure this out and I want to use the device at the full 200W. The calculation would be this: 100w per batt, divided by 6.4 (each batt low voltage of 3.2x2) = 15.625 then add 10% (1.56) on to that would be 17.185 amps??? So still 20amp batts would be fine?

Or if I had a 150W two batt reg. device - each batt at 75w divided by 6.4 = 11.719 + 10% (1.17) of that = 12.889amps? so again two 20amp batts would be fine.

 

[IMFire3605]

oh boy, k i understand partially. tell me if i have this right for the battlestar that is a 200w two batt regulated device. If just for the sake of seeing if I can figure this out and I want to use the device at the full 200W. The calculation would be this: 100w per batt, divided by 6.4 (each batt low voltage of 3.2x2) = 15.625 then add 10% (1.56) on to that would be 17.185 amps??? So still 20amp batts would be fine?

Or if I had a 150W two batt reg. device - each batt at 75w divided by 6.4 = 11.719 + 10% (1.17) of that = 12.889amps? so again two 20amp batts would be fine.

No, as the Battlestar is a Series battery config, not a Parallel Battery Config (in a Parallel you would do [Watts Set/Volts at lowest]/90%/2), so with the Battlestar being in series both batteries have to support and be capable of what amps are needed in the formula. Parallel configs you get the voltage of a single battery, MaH X number of batteries, CDR you get full CDR battery 1, then 50% more CDR each extra battery. Two completely different animals in the way they function.

So the Formula for the Battlestar is just this
(Set Watts/Lowest Voltage)/90%=Amps - Generally on average dual battery mod that is about 6.4v, so only the watts set needs to change in the formula, you can also reverse the formula to figure out max watts a mod will do

CDR Amps of Battery X 90% X Lowest Voltage = Max Watts

Examples

20 Amps X 90% X 6.4v = 115.2watts Max
25 Amps X 90% X 6.4v = 144 Watts Max
30 Amps X 90% X 6.4v = 172.8 Watts Max
30 Amps X 90% X 7.4v = 199.8 Watts Max (Will Be Pulling the Batteries at 50% Charge to stay there at 200watts)

 

[tangerine3]

That link above helped me tremendously thank you and mooch for making my transition of trying sub ohming go a lot smoother but just for my peace of mind . . . how did you get to the total sum of the equation below? I understand the 90watts divided by 6.4 (lowest voltage) = 14.063 but what math did you do with the 90% to get it to the total sum of 15.625amps?

"90watts/6.4v lowest/90%=15.625amps, to reach close to the 18.97amps"

Also the the other equations to find out max watts is good for me too.

 

[IMFire3605]

That link above helped me tremendously thank you and mooch for making my transition of trying sub ohming go a lot smoother but just for my peace of mind . . . how did you get to the total sum of the equation below? I understand the 90watts divided by 6.4 (lowest voltage) = 14.063 but what math did you do with the 90% to get it to the total sum of 15.625amps?

"90watts/6.4v lowest/90%=15.625amps, to reach close to the 18.97amps"

Also the the other equations to find out max watts is good for me too.

The 90% is an average number I use for figuring the mod control board efficiency, some it is 85% like the DNA75 control board, others like the DNA200 are 98% efficient, most Chinese mod control boards it is 90%, as the board takes some power to function so you have to take the into consideration of what is actually going on.

 

[tangerine3]

thanks i do understand what the 90% is for what i meant was what did you do with the 90% divide it with something, multiply it with something to the get final sum of 15.625amps

"90watts/6.4v lowest/90%=15.625amps, to reach close to the 18.97amps"

90 watts divided by 6.4 = 14.063 what was done with the 90% to get the total sum of 15.625amps?

sorry this is dragging on but I would like to know, thank you.

 

[IMFire3605]

NP, I use the first amp sum them divide that by 0.9 gives a final sum, also you can use this calculator that was just posted up to do the figuring for you

https://liionwholesale.com/pages/regulated-mod-calculator (would be good to bookmark this along with steam-engine.org for basic vaping needs)

3 Simple Variables

1) Number of batteries in drop down list
2) Set Watts or Desired Watts to figure for
3) Mod Chipset Efficiency Rating (Default is 90%)

Press Calculate

 

[tangerine3]

that link is perfect thank you! What I am finding out playing around with it is why do they even sell 200W devices when it looks like no battery is capable of vaping at that high wattage? I had to go down to 2 batteries, 150W 90% until it finally calculated 27.78amps, which is under the true highest battery amp rating of 30A.

e.g. some of the new TFV12 coils claim they can vape up to 200W, not that I'm wanting to do this at all, but for people that have not done any research and just think because a new device or coils say 200W, or now i'm seeing 350W devices, but you really can't even use them what is the point

 

[Carambrda]

that link is perfect thank you! What I am finding out playing around with it is why do they even sell 200W devices when it looks like no battery is capable of vaping at that high wattage? I had to go down to 2 batteries, 150W 90% until it finally calculated 27.78amps, which is under the true highest battery amp rating of 30A.

e.g. some of the new TFV12 coils claim they can vape up to 200W, not that I'm wanting to do this at all, but for people that have not done any research and just think because a new device or coils say 200W, or now i'm seeing 350W devices, but you really can't even use them what is the point

https://www.e-cigarette-forum.com/f...ngs-picking-a-safe-battery-to-vape-with.7447/

 

[conanthewarrior]

that link is perfect thank you! What I am finding out playing around with it is why do they even sell 200W devices when it looks like no battery is capable of vaping at that high wattage? I had to go down to 2 batteries, 150W 90% until it finally calculated 27.78amps, which is under the true highest battery amp rating of 30A.

e.g. some of the new TFV12 coils claim they can vape up to 200W, not that I'm wanting to do this at all, but for people that have not done any research and just think because a new device or coils say 200W, or now i'm seeing 350W devices, but you really can't even use them what is the point

Wattage wars- companies trying to out do each other with higher power mods, when they can only really output this power for a very short amount of time when the batteries are full, or are really stressing batteries to hit anywhere near this level.

The 350W mods use quad batteries, so run in a series-parallel setup, that is two batteries in series, with another two in series, wired together parallel.

This gives you the higher input voltage of series, allowing a higher wattage to be achieved without pushing the batteries insanely far, and also the benefit of parallel and the increase in available amps from this wiring.

For example, with a cutoff of 3.1V per cell, at 200W you would be drawing-
200/6.2=32.25A. Add in 90% efficiency, 35.84A, which is OK seeing as you also have the parallel wiring.

300W would bring you to 53.76A, so with 30A batteries it is possible. Not many people vape anywhere near this high though, and it really is just willy waving contest between the manufacturers.

 

[Carambrda]

Vaping at 400 watts on my RX300 with 20 amp batteries is possible. Just not for long...