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Are my batteries safe at sub-ohms?

Exodus_

Exodus_

I recently picked up a Smok Alien 220w along with 2 LGDBHG21865's (HG2) rated at 30A max discharge and 20A max continuous discharge. The octo-coil that comes with the Alien has a resistance of .15Ω and using the formula V/Ω=A, V being battery voltage, Ω being coil resistance and A being current, we find that 4.2V/.15Ω=28A which is approaching that limit of 30A. This seems to be a little dangerous, no?

As a new vaper I'm genuinely curious about these things and would love to hear some opinions of more experienced people.

EDIT - I realize that my formula uses the voltage for my battery when it is fully charged and could be less after some cycles and discharge. Maybe it isn't too much of a problem?
 
Last edited:
SirRichardRear

SirRichardRear

AKA Anthony Vapes on Youtube
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Exodus_ said:
I recently picked up a Smok Alien 220w along with 2 LGDBHG21865's (HG2) rated at 30A max discharge and 20A max continuous discharge. The octo-coil that comes with the Alien has a resistance of .15Ω and using the formula V/Ω=A, V being battery voltage, Ω being coil resistance and A being current, we find that 4.2V/.15Ω=28A which is approaching that limit of 30A. This seems to be a little dangerous, no?

As a new vaper I'm genuinely curious about these things and would love to hear some opinions of more experienced people.

EDIT - I realize that my formula uses the voltage for my battery when it is fully charged and could be less after some cycles and discharge. Maybe it isn't too much of a problem?
Click to expand...
Hi and welcome to the forum!

for regulated mods such as the alien, the formula to calculate amp draw is power(watts)/V(voltage of the batteries)= Amps
I usually use the nominal voltage of 3.7 but some like to use the cutoff voltage of 3-3.2. a general rule of thumb is 75 watts per 20 amp battery. so having 2 batteries you can go up to 150 watts safely in your alien. i wouldn't push over that. the resistance is irrelevant for amp draw of the batteries in regulated mods. also some people like to factor in board efficiency (90%) so for example Power (100 watts)/Input voltage (7.4 nominal for dual series mods) / .9 efficiency = 15 amps on your battery

I made this video explaining it a little more on my youtube channel. it's a pretty good watch IMO and informative. and of course i'm always here to answer more questions if you have them ;)
 
Exodus_

Exodus_

PhantomOp said:
@Exodus_ --- Damn --- sorry man! Welcome to VU!! :wave: I forget the simple shit sometimes. :)
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Thanks! Hahahaha
PhantomOp said:
@SirRichardRear --- I'll let you fill in the technical details on his batteries.

also -- LG HG2 batteries are not a CDR of 20A ... they are only tested at 18A CDR.

MOOCH's Recommended Batteries
Click to expand...

That picture is actually extremely helpful, thanks a lot.
SirRichardRear said:
Hi and welcome to the forum!

for regulated mods such as the alien, the formula to calculate amp draw is power(watts)/V(voltage of the batteries)= Amps
I usually use the nominal voltage of 3.7 but some like to use the cutoff voltage of 3-3.2. a general rule of thumb is 75 watts per 20 amp battery. so having 2 batteries you can go up to 150 watts safely in your alien. i wouldn't push over that. the resistance is irrelevant for amp draw of the batteries in regulated mods. also some people like to factor in board efficiency (90%) so for example Power (100 watts)/Input voltage (7.4 nominal for dual series mods) / .9 efficiency = 15 amps on your battery

I made this video explaining it a little more on my youtube channel. it's a pretty good watch IMO and informative. and of course i'm always here to answer more questions if you have them ;)
Click to expand...
This clears everything up, really appreciate it :)
 
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