1. Double Tap's Avatar
    Is there a way to test the ability of the battery in my Nexus 4 to hold a charge and the actual capacity. As many of you know if you own a car it is possible to do a load test to check the health of the battery. Is there a similar way to check my phone battery?

    Posted via Android Central App
    02-11-2015 04:06 PM
  2. Rukbat's Avatar
    The same way - load testing. Is there a device to do it? No. You have to fully charge the battery, put a load on the battery that will draw about half the capacity, then measure the voltage. It should be 3.60 or a little more.

    What's a load that will draw half the capacity? R = I / E, so if the battery has a capacity of 2.1 Amps (a 2100 mAh battery), 2.1 / 3.6 = 0.5833 Ohms. The resistor would have to be able to handle at least 10 Watts. (You can't buy that value, you'd have to make it from resistance wire, or by connecting a few resistors in a series/parallel connection to get close.)

    The normal way to check it is that if it's over 18 months old and doesn't seem to hold a charge, it's bad. (They're less that $10, so if you have a reasonable repair shop it shouldn't cost that much to have it replaced.)

    And if you want to keep it running longer, Read Is My Battery Shot? (You can start at the 4th paragraph from the end if you don't want to read the whole thing.)
    02-11-2015 05:18 PM
  3. Double Tap's Avatar
    The same way - load testing. Is there a device to do it? No. You have to fully charge the battery, put a load on the battery that will draw about half the capacity, then measure the voltage. It should be 3.60 or a little more.

    What's a load that will draw half the capacity? R = I / E, so if the battery has a capacity of 2.1 Amps (a 2100 mAh battery), 2.1 / 3.6 = 0.5833 Ohms. The resistor would have to be able to handle at least 10 Watts. (You can't buy that value, you'd have to make it from resistance wire, or by connecting a few resistors in a series/parallel connection to get close.)

    The normal way to check it is that if it's over 18 months old and doesn't seem to hold a charge, it's bad. (They're less that $10, so if you have a reasonable repair shop it shouldn't cost that much to have it replaced.)

    And if you want to keep it running longer, Read Is My Battery Shot? (You can start at the 4th paragraph from the end if you don't want to read the whole thing.)
    Thanks very much. Your response and the linked information you posted are very informative and appreciated.

    Posted via Android Central App
    02-11-2015 05:34 PM
  4. A2user's Avatar
    I was just perusing this thread and noticed ' R = I / E, so if the battery has a capacity of 2.1 Amps (a 2100 mAh battery), 2.1 / 3.6 = 0.5833 Ohms'. Ohms law is E=I * R, so R=E / I. Also, 50% battery capacity (the link suggests 25%) is 1.05 amps. If you want to measure the voltage at 50% then R = 3.6 volts / 1.05 amps =~ 3.4 ohms. A 5 watt resistor should be fine.
    07-16-2016 08:03 PM

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