Laptop Battery voltage, mah and Wh Method of calculation

Recognize the laptop battery parameters, the purchase of a laptop battery can not just look at the cores. 

What is the biggest features of the laptop comapre with the desktop, I think it contain a laptop and can operation independent is one, this is the greatest significance - allow people to getoutside to go with.(Nikon EN-EL5 Battery)

In this case, choose the battery become a necessary part when buying a laptop, However, as a consumers, the most intuitive is the number of batteries cells. Most laptops in the market  standard 8-pin, 6-cell or 4-cell lithium-ion battery. The standard 4-cell lithium-ion batteries are often ultra-thin products, such products can often choose batteries that have more cells to get longer standby time. For two different number of batteries notebook products, in general, more cells batteries have longer standby time.(Acer Aspire 5720 Series Battery)

There are also some friends that have a better understanding of the notebook computer pay more attention to the size of the battery’s “mah” unit when choosing a product, “mah” is the battery’s capacity unit. In general buying, many people may think that bigger “mah” unit battery will have longer life time,  But the reality is not the case, we can often see  the 6-cell 4400mAh "," 4 core 2200mAh " nominal value  batteries on the laptop battery, over time we all think that 4400mAh or 2200mAh capacity directly determines the working hours of the notebook.(HP Pavilion DV4 battery)

But the fact is not this case, the truly master a unit of battery capacity should be considered the "Wh", of course, the "Wh" and "mAh" have a close relationship with the following formula: Wh ÷ V × 1000 = mAh, it’s should be point is that the unit of measurement the electrical power consumption is power, that’s “W”.(Dell Inspiron 1525 Laptop Battery)

Thus we can learn that what we should pay attention to is not the “mah”, but the “wh” and the voltage number, for-expample the same 4400mah battery have different standby time when they are in 10.8V and 11.1V different voltage, and this different comes from the difference of "Wh" . By calculating we can get the following equation:

4800÷1000×10.8=51.84（Wh）

4800÷1000×11.1=53.28（Wh）

It can clearly seen that the 4400mah battery in 11.1V voltage have advantages on the battery life time.