Battery/Charging How to charge the battery correctly

  1. F_Adrian_Petrugan_ZCKR Donut Feb 12, 2018

    F_Adrian_Petrugan_ZCKR, Feb 12, 2018 :
    Hello .I'm buying a oneplus 5t this week and i want to know how to correctly charge the battery in order to have a healthy life .
    Some people say "don't let it less than 20% and higher than 90%" .
    Should i do that ?
    Thanks for your time .

  2. Lauvindra Raj Cupcake Feb 12, 2018

    Lauvindra Raj, Feb 12, 2018 :
    It Is true if u wanna maintain a good battery health....But if u accidentally Charged it up more than 90% or less than 20 % once in a while it doesn't matter.As long as u don't overcharge overnight or use phone while charging it is all good.

  3. farawana Cupcake Feb 12, 2018

    farawana, Feb 12, 2018 :
    are you sure about the 90% and 20%?
    normally it should stop charging after it is full and some say it should get empty from time to time, on order for the battery to know where the lower limit is or when it is empty.
    I don't know?!

  4. akshayr723 Honeycomb Feb 12, 2018

    akshayr723, Feb 12, 2018 :
    it's not always 20% to 90. I have read in many websites that 30% to 80% is the optimal value. Also once in a month calibrate your battery by completely discharging it and charging to 100%.

  5. Sridhar Ananthanarayanan Lollipop Feb 12, 2018

    Sridhar Ananthanarayanan, Feb 12, 2018 :
    1. don't let the battery go below 10% (once in a while won't do any harm).
    2. don't leave it connected to the charger for too long after it is fully charged (once in a while won't do any harm).

    taking care of the above two will keep your battery healthy throughout it's 'useful' life.

  6. F_Adrian_Petrugan_ZCKR Donut Feb 12, 2018

  7. G_Michał_L_VJCp Gingerbread Feb 12, 2018

    G_Michał_L_VJCp, Feb 12, 2018 :
    As electrical engineer working with batteries I can say a few things:
    1) Discharging to 0% and charging to 100% as a "calibration" is pure bullshit. Does nothing good for your battery and only harms it because li-ion batteries doesn't "like" to be discharged to low capacity. I wouldn't say 0% capacity because battery management system probably turns of the phone before capacity goes to TRUE 0% and not 0% showed on your screen.
    2) You can charge your phone to 100% everytime and you can leave it over night plugged at 100% for the whole night. Charging to 100% of what BMS allows doesn't harm your battery AT ALL. In fact number of charging cycles for li-ion batteries is based on DOD which is Depth of discharge e.g. >1000 cycles @ 100% DOD, >2000 cycles @ 90% DOD etc. Depends on a paricular lithium battery, manufacturer etc. And as to leaving phone connected to charger when it's already 100% does NOTHING because BMS disconnects the charger itself, you don't have to do it by unplugging the battery. Lithium battery has to be controled this way or else it blows up (literally). When you have 100% battery and your phone is still connected to the charger, battery is on stand by and your phone use power from charger only. That's why you'll always have 100% battery while plugged.
    3) The moment BMS decides to end charging is usually when current reaches so called CUT OFF value which means battery can no longer take current that is more than e.g 150mA so when your phones charges <150mA for a set period of time, BMS knows it's fully charged and it has to be disconnect or else the voltage can rapidly increase, overloads battery and cause the damage, usually blow-up.
    4) The process of charging li-ion batt goes like this (let's start from full current):
    a) CC (constant current) stage which means the battery takes full current, in this case 4A but frankly it's 3,4-3,6A.
    For 3,3Ah battery it's current around 1,1C, it's perfectly good value for battery life.
    b) when battery reaches certain point of voltage (on Dash I noticed it's around 60-70% approx.), current drops naturally and it keeps going down with increasing voltage
    c) CV (constant voltage) means BMS sets 4,2V (usual value for 100% capacity of lithium cell) and current is going to 0A since your battery is almost charged at this point e.g 4,1V and charger gives 4,2V which is 4,2-4,1V = 0,1V, it allows really low current. But it's important to charge to 100% because last stage lasts long but it gives you significantly more capacity, especially for only 3,3Ah cell. Moreover, this stage is most dangerous because voltage for almost fully charged cell becomes unstable and when it takes current, it'll increase voltage easily and rapidly. That's why cut off current has to work and stops charging when it's time. The process can go a few times e.g. if battery goes >4,2V, the charger disconnects, waits few seconds, lower current from charger and starts charging again. And after e.g. 3 repeates, it ends the charging process for good.
    5) In a nutshell, don't let your battery discharge lower than 10% and it'll keep capacity longer. That's kind of additional way to enhance battery life because BMS itself will never let your battery to discharge to 0% capacity. They can't allow it because number of cycles would be too low and capacity would drop too fast. You can charge to 100% everytime and keep it through the night, it'll do no harm at all. And if you can, you use your phone connected to the charger when battery's full. That way you don't use your battery at all.

    Last edited: Feb 12, 2018

  8. akshayr723 Honeycomb Feb 13, 2018

    akshayr723, Feb 13, 2018 :
    Thanks for enlightening us and breaking myths on battery backup. Many internet sites give wrong information about battery backup.

    I think you should write a new thread about it. It would help alot of people.

    moiz msm, farawana and Romain_Daudin like this.
  9. farawana Cupcake Feb 13, 2018

    farawana, Feb 13, 2018 :
    I agree with akshayr723. thanks a lot for the detailed explanation.


    akshayr723 likes this.
  10. fede.sax92 Cupcake May 21, 2018 at 8:32 AM

  11. Matt 80 Jelly Bean May 21, 2018 at 4:23 PM

    Matt 80, May 21, 2018 at 4:23 PM :
    Well said, I'm fed up of all this leaving your phone on charge overnight damages your battery BS. I've done it for years and never had any issues.

    davidonewell likes this.
  12. davidonewell Cupcake May 22, 2018 at 12:36 AM