With the rapid emergence of multiple cell mods, especially lipos, i thought it would be an idea to help people gauge the battery life.
It is far easier to convert both to Watt hours, or Wh and use those figures to determine the battery life.
As we all know, higher mAH (milliAmp Hour) batteries last longer, so the higher the mAH, the longer it will last, right?
On a single battery mod or parallel mod, yes, you can add the capacities together. On a series setup, its not that simple.
This calculation applies to any series mod, from the 2x 18650s to 3s lipos and more.
(mah x nominal volts) / 1000 = Wh
Nominal volts is the batteries mid point. The majority of the ones we use are 3.7V nominal.
With multiple cells, you do:
number of cells x 3.7 = pack nominal voltage
So a couple of examples would be:
2x18650 series
Powered by 2x samsung 25r batteries 2500mah. The equation here is
(2500 x 7.4)/1000 = 18.5 Wh
3s lipo
In this case i will use a 3s 1300mAH battery
The equation is
(1300 x 11.1)/1000 = 14.43 Wh
If you have the Wh figure, you can turn the equation around to get the individual cell mAH capacity too. So it would become:
(14.3 x 1000)/11.1 = 1300
(Wh x 1000) / nominal volts = mAH
It is far easier to convert both to Watt hours, or Wh and use those figures to determine the battery life.
As we all know, higher mAH (milliAmp Hour) batteries last longer, so the higher the mAH, the longer it will last, right?
On a single battery mod or parallel mod, yes, you can add the capacities together. On a series setup, its not that simple.
This calculation applies to any series mod, from the 2x 18650s to 3s lipos and more.
(mah x nominal volts) / 1000 = Wh
Nominal volts is the batteries mid point. The majority of the ones we use are 3.7V nominal.
With multiple cells, you do:
number of cells x 3.7 = pack nominal voltage
So a couple of examples would be:
2x18650 series
Powered by 2x samsung 25r batteries 2500mah. The equation here is
(2500 x 7.4)/1000 = 18.5 Wh
3s lipo
In this case i will use a 3s 1300mAH battery
The equation is
(1300 x 11.1)/1000 = 14.43 Wh
If you have the Wh figure, you can turn the equation around to get the individual cell mAH capacity too. So it would become:
(14.3 x 1000)/11.1 = 1300
(Wh x 1000) / nominal volts = mAH
