TechSpot

About laptop battery

By nismo91
Mar 5, 2009
  1. Hello all,

    i just wanted to ask simple question regarding laptop battery. no worries, i wont ask about how to keep em long, just analysis about the battery capacity.

    i noticed that many ppl uses different standard to define battery capacity.
    there are mWH, mAh, as well as cell count.

    i suppose the mWh is equivalent to the voltage of battery times mAh.

    so, i wanted to ask, how to determine that a battery of laptop will last longer? since many laptop comes with different voltages. some 10V with 4000mah, some 15v with 4000mah is it going to provide same hours since those batteries have same 4000mah but have different voltage rating?

    i hope someone have reference or from the net since i've spent time googling and find no result. i found one said 71W battery 8-cell, others 48.8W 6 cell. while others said 6-cell is usually 4400mah and i do not understand the conversion unit.
     
  2. jobeard

    jobeard TS Ambassador Posts: 13,469   +327

    The Volt, AH ratings have nothing to do with Useful Life expected from the battery.
    The cell count may relate, but the bottom line is the means to create the storage in the first place:
    1. lead acid
    2. nickel-metal-hydride (NiCad)
    3. Lithium-ion (LI-on)
    There's a shelf life that limits the AGE of the battery regardless of V/AH ratings.
    See the Wiki on LI-on
     
  3. Tedster

    Tedster Techspot old timer..... Posts: 10,074   +13

    irrelevant, you're not comparing the same things. mWh is not the same as mAH or AH. And different loads, CPUs, circuits, and battery types all have different loads and capacities.

    You can compare an AH battery with another one of the same cell capacity, but in reality, different boards will mean different results, plus external factors such as shelf age etc...

    Go by professional reviews and lab testing if you want an average consensus of battery run times for a laptop.
     
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