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Question: When I buy a Dell Laptop, I get the following choice for battery:
(Lithium-Ion main battery with X cells and Y Wh [included in price/at additional $]

  • Lithium-Ionen-Hauptakku mit 4 Zellen und 24 Wh [Im Preis enthalten]
  • Lithium-Ionen-Hauptakku mit 9 Zellen und 85 Wh [zuzgl. CHF 120.01]
  • Lithium-Ionen-Hauptakku mit 6 Zellen und 46 Wh [zuzgl. CHF 30.00
  • I figured that I can calculate that a 86 Wh offers +254% of the 24 Wh lifetime, but...
    Is there any way to calculate to what battery time this amounts in hours ?
    I mean how many hours will the 24 Wh last (at normal operation - eg. writing a document - not watching video), else the +254% is a pretty useless number...
    Also anybody knows whether 4 cells means 4 times 24 Wh, or 24 Wh in total?

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    Depends on what you're using the laptop for. The more intense your experience, the more you can fizz pop. –  random Jan 30 '10 at 12:23

    1 Answer 1

    up vote 2 down vote accepted

    Only if you know the power consumption of the laptop. The rate at which it uses the charge in the cells.

    And presumably, as the number of cells changes, the output voltage is regulated by electronics in the laptop, or there are series/parallel connections so the voltage for the circuity stays the same. Circuitry likes that.

    You would need to know what current is consumed, at what voltage, so you can divide the Wh (Watt hours) by voltage and current to give the number of hours.

    It's obviously directly proportional to the Wh figure. More money, more hours.

    My interpretation is that 4 cells gives 24 Wh in total.

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