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Whats it with phones not allowing the flash light under 5%. As if i cant fkn decide myself how to use my battery.

Comments
  • 3
    I agree, but it's likely to stop over taxing the battery and causing a possible battery overload (boom).
  • 6
    You need to enter level 7 override authorization code.
  • 3
    @sariel This is my guess as well.

    Though that always irritates the hell out of me, too. It’s my device! Let me use it how I want! But yeah, there’s probably a good reason here.
  • 0
    @sariel it's probably not for a good reason but rather just to prevent the user from draining the battery fully.
  • 0
    @electrineer yes, but that can lead to higher rates of a battery exploding.

    Think of it like a bell siphon. The device will collect all the energy the battery has to give as fast as it can. This causes the battery to overheat. Eventually the plastic liner between the layers of lithium melts and fails causing a bridge and then an electrochemical reaction to happen.

    💥

    It may only happen 10% of the time, but 10% of the estimated 17 billion phones in the world is still 1.7 billion potential phones exploding.
  • 0
    @sariel if that was ever the concern, you wouldn't prevent it by disabling the operation at below 5% because you'd end up overheating the battery anyway.
  • 0
    @electrineer they could avoid the whole situation by displaying a percentage that's actually lower than what the battery is at, and then allowing your battery to hit "0%"

    But that would require more logic to display negative battery percentages(because it will happen).
  • 2
    @sariel 0% doesn't mean that there's no energy left in the battery anyway. Fully discharging a li-ion is unsafe, so 0% is well before that, and there should be hardware protections after that, still.
  • 2
    i remember measuring battery levels in Voltage Numbers, and there is a thereshold voltage, that you shouldnt get lower if you draw larger amounts of power.
    Anyways. On Li-on batteries the 100% limit usually is something around 4.2V
    and the 0% Limit is 3.0V. However, since the relation is NOT linear, the last few Percents have a large drop in Voltage Levels and therefore should be managed with Caution. Under no circumstances you want to drop under the lowest voltage, unless you want to short and kill the battery.

    The reason the 5% rule is in place, is to prevent users from themselves, by giving them enough time to turn off the device. Ideally you shouldn't be able to run any games or other intensive apps on that percentage aswell, but ya can't prevent everything, right?
  • 1
    @thebiochemic yea but the phone turns off before the battery is empty anways
  • 0
    @joewilliams007 at this point the lifetime of your battery has suffered already, and is a measure to prevent loss of data.
  • 1
    @thebiochemic what? The device is gracefully shut down before the battery is damaged, and with enough margin that it won't get damaged even if you can't charge it immediately.
  • 1
    @electrineer well yes, but actually no, the ideal range for a battery is between 20% and 80%.
    At less than 5% you're well out of the ideal range, and in the safety zone, where your batteries lifespan has already suffered, when done on a regular basis. Obviously on top of that you have a margin for deep discharge, for not terminally breaking the battery.

    For a better illustration, on how a battery discharges, take a look at the graph on this site for example:
    https://learn.adafruit.com/li-ion-a...
    where you can clearly see, what's going on, and what the implications of it are.
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