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  • Trying to understand math for Battery resistance ?

    From StevWolf@21:1/5 to All on Tue Jan 24 05:28:30 2023
    I’m working though understanding this description in this book. see attachment link below.
    I have tried this method for testing household batteries. I know there are other ways of testing batteries, but really I'm just trying to work my way through this book as a personal exercise.
    Please refer to link below for the book example Im trying to follow. The hand written notes are mine based on what things the terms mean. Hopefully I have them right.
    Can you tell me If I am performing the example properly.
    Here is the math using the equations in the document, step by step broken down based on the formula given in this book.
    1. VL/RL = IL
    2. VNL – VL = NewVL
    3. NewVL/IL = RI

    My Tests

    1.5 Volt Battery (Good Battery)
    I have an (A) Size 1.5 Volt battery, the following are my results.
    VNL 1.569 No load.
    VL 1.548 Load tested with R100 Resistor.
    RL R100 Ohm Resistor

    1. VL/RL= IL 1.548 / R100 = 0.1548 (IL)
    2. VNL-VL= (NewVL) 1.569-1.548= 0.021 (NewVL)
    3. VLNew/IL=RI 0.021/.1.548=0.1356589147286822 (RI)

    The final result and internal resistance is 0.13 Ohms.
    However when I go to the following web site https://www.translatorscafe.com/unit-converter/en-US/calculator/batt-internal-resistance/
    And punch in the numbers I come to 1.357. Yes it’s the same number rounded up, but why is my number 0.13 and the web site moving the decimal place.1.3 Where am I wrong ?? They do seem to use a different math I think (This type of math is not my strong
    suit so Im not that clear on it.)
    Who is right the web site my book or is my understanding / math wrong?

    Here are the pages from the book that Im using. I hope they come through, I don't post many pictures and things.
    thank you very much.

    [img]https://i.imgur.com/dyOeMjn.png[/img]

    Here are the numbers I have entered into the www.translatorcafe.com web site calculator.
    [img]https://i.imgur.com/NcVwyMk.jpg[/img]

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  • From Frank@21:1/5 to StevWolf on Tue Jan 24 16:43:44 2023
    On 2023-01-24, StevWolf <colinmarr0@gmail.com> wrote:

    1. VL/RL= IL 1.548 / R100 = 0.1548 (IL)

    1.548 / 100 = 0._0_1548

    3. VLNew/IL=RI 0.021/.1.548=0.1356589147286822 (RI)

    0.021 / 0.01548 = 1.357

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  • From stevwolf58@gmail.com@21:1/5 to All on Tue Jan 24 09:59:15 2023
    1. VL/RL= IL 1.548 / R100 = 0.1548 (IL)
    1.548 / 100 = 0._0_1548

    3. VLNew/IL=RI 0.021/.1.548=0.1356589147286822 (RI)

    0.021 / 0.01548 = 1.357

    Human error,
    Thank you, Carless of me.
    Regards

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