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battery. Is it ok to let the charge go right down to almost zero

Discussion in 'Android Devices' started by Fred Bassett, Jan 1, 2012.

  1. Fred Bassett

    Fred Bassett Member
    Thread Starter

    is it ok nowadays to let a new battery go down to to 5% once its been fully charged the first time out the box? Or will this affect the long term life of the battery.
    Is there a % of battery life you normally wait till you charge it back up again?

  2. Szadzik

    Szadzik Extreme Android User

    With Li-Ion and Li-Po batteries it is not advisable to discharge them to very low levels. Start charging at around 20%.
  3. Fred Bassett

    Fred Bassett Member
    Thread Starter

    is this what would of turned the battery life of my first razr from amazing to crap as i let it go right down the first few times. I'm still blaming the update lol

    I had this email from VZW support and it said "It's actually recommended to let the charge go as low as possible"

    I'd ratther believe the users on forums tbh
  4. Szadzik

    Szadzik Extreme Android User

    They are talking about old batteris with memory effect that Li-Ion and Li-Po vbatteries do not have. It will do more harm than good.
  5. Fred Bassett

    Fred Bassett Member
    Thread Starter

    Appreciate it.. thanks for your help. I'll let it go down to 20 like you said
  6. Podivin

    Podivin Android Expert

    I charge mine every night. If that means I'm charging at 20% or 60%, it doesn't matter to me.
    I don't generally let it go much below 30%, but that's just because I won't to make sure it's ready for use if/when I need it, rather than because of any particular need of the battery.
    Trooper likes this.
  7. Trooper

    Trooper Android Expert

    +1 same here.
  8. edstewbob

    edstewbob Well-Known Member

    According to the batteryuniversity.com website Lithium-Ion longevity is greatly increased by avoiding deep discharge/recharge cycles. The number of estimated discharges is greatly increased by reducing battery temperature and higher current levels saying that the battery wears out faster like any mechanical device with higher levels of usage and the depth of discharge impacts the number of recharge cycles. See the discussion here:
    How to Prolong Lithium-based Batteries - Battery University

    The same is true for my Prius NiMH battery where the battery level is maintained between 45%-75% maximum charge level to increase battery life.

    Neither Lithium-Ion nor NiMH batteries exhibit memory effects like NiCD batteries.
  9. you2

    you2 Android Expert

    Does this imply it is better to not charge to 100% ?

  10. edstewbob

    edstewbob Well-Known Member

    Yes but it is not practical for our phones. Once the phone reaches 100% charge it stops charging anyhow so there is no additional heat buildup during the charge cycle. For my Prius the charge/discharge happens continuously while driving so there is a lot of heat/friction that can lower the battery life and it has it's own control module and heat control built in so it can automatically manage the charge level.
    Goldchamp likes this.
  11. Szadzik

    Szadzik Extreme Android User

    Yes, it does.
  12. Goldchamp

    Goldchamp Grand Admiral

    Yeah what he said :) It's just not practical even tho it might be better.
  13. Frisco

    Frisco =Luceat Lux Vestra=

    Well, it changes the charging force, mostly down, but also back up as the cycle is triggered by what voltages/current are detected by the charging circuit apparatus.

    It's amazing how sophisticated batteries are now, especially Lithium-Ion units which are common in phones and laptops, etc.

    The whole notion of "over charging" is pretty much gone now. On the other end of the spectrum, "over draining," it is the device which can suffer, not the battery. The device may get caught in the middle of a service process with too low of resources to complete that process, and strange things can happen.

    So, as stated above by the Guides, it is best to avoid draining the unit to the point of shut down (some begin prompting at about 15% anyway): plug the thing in often, it does not hurt a LI battery to "top" it.
    edstewbob likes this.
  14. Fred Bassett

    Fred Bassett Member
    Thread Starter

    i'm thinking the same, charge at 20 or so. Everyone has a different opinion thats for sure lol. Battery life is affected by that OTA update though
  15. Frisco

    Frisco =Luceat Lux Vestra=

    When you have some spare time, read here:

    Charging Lithium-Ion Batteries ? Battery University

    That whole site is quite informative about batteries, but that linked page focuses on charging LI batteries. ;)
    edstewbob likes this.
  16. edstewbob

    edstewbob Well-Known Member

    Based upon this information for fixed battery phones like the RAZR it would be nice to have an app that limits the charge level to say 90 or 95% as this should increase battery life and run time as the battery slowly degrades over time. Although the voltage for a fully charged battery will reach the maximum 4.2V over time the mAh power contents will lessen so after 6-12 months usage a 90% charge level may have as much power as a battery that has always been charged to the 100% level. At least that is what I get from the batteryuniversity.com article but I'm not sure if the results would be significant enough to even notice the difference.
  17. Szadzik

    Szadzik Extreme Android User

    It would be worth a try, but as currently no one keeps one phone for very long, there would be little gain.
  18. you2

    you2 Android Expert

    Part of the problem here is that the circuit might already be preventing it from reaching 100%. I.e, is 100% 100% ? The article made it sound like some batteries address this issue by not allowing 100% charge and others do not. How can you tell ?

  19. Frisco

    Frisco =Luceat Lux Vestra=

    Without sophisticated lab equipment, you can't tell what the true (constantly changing) remaining charge is in a battery. Even calling it a "percentage" of full charge is kind of silly. ;) Look at the (so-called) battery percent meter, then reboot. Often that percentage will be higher once the device is powered back up, which is interesting given the amount of energy required to power down and then back up a phone.

    Indeed, some of the "charge" is not in the battery at all, but in portions of the capacitive circuitry. Again, it's complicated, and one important component of the whole issue of battery charging is the deceptive, inaccurate nature of the battery meter itself, even specialized battery monitoring apps/widgets can't tell us exactly what's going on, although they purport to do just that.

    They come close sometimes, engineers tell us. But we rely on them too much when all we need to do is just keep the danged thing charged up. :D
  20. edstewbob

    edstewbob Well-Known Member

    Yes you are right according to the article most good quality chargers will consider 4.2V the 100% point even though they could be charged to a higher voltage. My battery widget showed 3.91V at 70% charge level while discharging and 4.09V while charging. This was the case at any charge level, the voltage always showed higher when I was in charging mode rather than discharge mode, which kinda makes sense to me but I was surprised to see that. I may be making a bad assumption but I suspect most of our cell phones have good quality chargers in order to maximize battery life and longevity so probably don't typically overcharge too far above the recommended 4.2V.
  21. AndroidGreg

    AndroidGreg Member

    My phone reaches 4.39V fully charged on the charger still and goes to 4.34 unplugged. Battery life for me is 16 hours about on LTE and 20 on cdma only. I am not worried at all about battery longevity on this because in 20-24 months I will be upgrading. If it gets bad before my upgrade I will warranty with my 2 year warranty or insurance.

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