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Help my daughter (and me) with a science project!

Discussion in 'Homework Help' started by stljoe, Mar 7, 2016.

  1. stljoe

    stljoe New Member

    Mar 7, 2016
    Short story: my daughter wanted to do her science fair project on hearing aids since she wears them and decided to compare the life of various batteries. We decided to see if we could run a 1.5v AA battery operated clock off one and see how long it lasts. The problem is it is lasting too long to be an efficient test since we have to run tests on 4 different batteries and repeat 3 times.

    I'm trying to adapt other "battery drain" circuits that I've seen here and other places online but with no success. Most include including a small resistor in parallel to decrease the time the battery will run. I want the clock to run for a while, maybe a few hours, but not for the 7+ days it's been running without any additional load. It's running right now with a 10 ohm resistor (the smallest I could find locally) but I'm wondering if that will still take too long. I tried to put two 10 ohm in parallel to create a smaller resistor but the clock stops?

    Sorry for the elementary question but any help would be appreciated!
  2. audioguru

    audioguru Well-Known Member Most Helpful Member

    Mar 16, 2004
    Canada, of course!
    The tiny #312 zinc-air button battery in each of my hearing aids lasts for 8 days when I turn off my hearing aids each night. I am told they run down in about 2 weeks if the seal is removed and they are not used for anything.
    I think if you severely overload the battery then the test will not be valid. The Energizer datasheet shows that it is rated with a load of 150 times your 10 ohms.

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