How to get a close estimate of how long your battery will last.

[yepimonfire]

Things you need to know:
The mAH rating of the battery
The voltage of the battery
An approximate value of the resistance rating of your cartomizer in ohms
The cutoff time of our battery OR the amount of seconds you usually take a drag for

Start with this: the mAH rating of the battery/1000/(voltage/carto resistance)*60²/the length in seconds of each drag (or cutoff time if you drag the entire time)/an estimate of the amount of puffs you take per session. This will give you an estimate of the amount of sessions you will get from a full battery to a dead battery. if you want to know how many puffs in total, simply stop the equation after dividing by the drag time.

For example

I have a 1600mah battery and 2.6ohm cartos. The battery has a 7 second cutoff and i use it the entire cutoff time.

1600/1000/(3.7/2.6)*60²/7/20= ~29 sessions at 20 puffs with a 7 second drag time.

 

[paulishuku]

Would this formula work the same with stacked batteries on a variable voltage device? =)

 

[yepimonfire]

EDIT: just multiply the mAH rating of one battery by the number of batteries in the device. this will only work for a CONSTANT voltage. so if you set the voltage to one voltage and leave it there, than the equation is valid, if you're constantly messing with it, you could get a very rough estimate by averaging the voltages you usually vape at and plugging that into the equation.

 

[yzer]

Question. Most people don't run a Li-ion battery down until it's dead. Most recharge the battery when it reaches somewhere between 3.4 and 3.7V. Li-ion is fully charged at approx 4.19V. How does this affect your formula?

 

[yepimonfire]

Question. Most people don't run a Li-ion battery down until it's dead. Most recharge the battery when it reaches somewhere between 3.4 and 3.7V. Li-ion is fully charged at approx 4.19V. How does this affect your formula?

The whole reason i came up with this formula is for myself. when i was working long shifts at my last job, i had no opportunity to charge any of my batteries, i had a 380mah battery at the time and it always died before my shift was over, so i wanted to figure out how high of a mAH battery i would need to get me through the entire day. this formula allowed me to figure out whether or not a certain battery would cover me the entire day without going dead. you could possibly figure out at what percentage of battery life the voltage drops to a point you feel it needs recharged, and then multiply the entire answer my that. let's say your batteries voltage drops below where you'd like it to be at 75% used. multiplying my answer (29) times .75 gives me 21 uses with 7 second draws and 20 hits per session. theres plenty of things you could do to tweak the formula with different points of data. the original one is simply total up time from full to dead.

 

[Thrasher]

a certain battery would cover me the entire day without going dead.


Instead of going crazy with the math to figure out how long a lil 510 ecig battery will last just get one 1100 or 1300 mah ego or vision battery and be done with it for the next 10 hours.

 

[yepimonfire]

a certain battery would cover me the entire day without going dead.


Instead of going crazy with the math to figure out how long a lil 510 ecig battery will last just get one 1100 or 1300 mah ego or vision battery and be done with it for the next 10 hours.

you could do that. but its fun to know how long it will last either way

 

[Thrasher]

you could do that. but its fun to know how long it will last either way

lol and you sir are correct. im the same way sometimes i do more work then i should to figure out a solution when there is an easy way out in front of me.........................