[CDMA] Battery calibration after rom/kernel change

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  1. z50king

    z50king Well-Known Member

    have you guys calibrated battery? either via recovery or with the app? My battery life has dropped off significantly since I did, wondering how long it takes to come back

    I have some news about battery calibration while using Team Win Recovery:
    After you 'calibrate' the battery by either using Battery Calibration from the market or via your recovery you are supposed to charge the battery to 100% and then let the phone completely die on battery. After it dies you will need to plug it into the charger for 10-20 minutes until Team Win Recovery will let you unplug the power cord and then power on the phone. After the phone dies and you plug in the charger Team Win puts the phone in recovery mode, meaning that you cannot power on the phone until the charger is unplugged. And you cannot use the volume rocker or power button while in this recovery mode.

    It's just useful info as it scared me the first time. if you adb during this time you will see that the phone is in recovery. I'm sure Team Win will fix this soon.

  2. grepper

    grepper Well-Known Member

    After booting Senseless ROM, I read that battery life can be boosted simply by wiping battery stats. Sounded too easy. So, I thought I'd prove them wrong. Charged battery to 100%, then booted to recovery, and wiped battery stats. I did this each morning for three days. Over those the days, my battery life improved my about 40%. Originally had to charge by 2-3pm. Stretched to 1030pm.

    Worth the 2 minutes it took to clear the data.
  3. JD_from_da_80s

    JD_from_da_80s Well-Known Member

    How do you calibrate your battery? Never heard of it.
  4. z50king

    z50king Well-Known Member

    You only need to wipe the battery stats once, then the phone rewrites the stats and follows them.

    you can do it from recovery in wipe mode, or you can download battery calibration app and give it root access. you don't need to wait to wipe until 100% as long as you are charging it to 100 before you take it off the charger.
    JD_from_da_80s likes this.
  5. EarlyMon

    EarlyMon The PearlyMon Moderator

    I thought that this was important enough to cull out some posts and start a thread for this. I know it's already come up a few times.

    Battery Calibrator by Potente - note that there are a few of those in the Market, but that's the one I have used.

    Onscreen instructions are crystal clear. It simply deletes a stale file, you and the phone take it from there.
  6. z50king

    z50king Well-Known Member

    I addded some info to the OP. mainly about the phone after it dies when running Team Win Recovery
    EarlyMon likes this.
  7. EarlyMon

    EarlyMon The PearlyMon Moderator

    I'm on Clockwork Mod, so I'm going to stand by my app advice for CWM users like me that feel ok trusting the app. I read thru the descriptions of a few before settling on that one.

    I ran my phone until it shut itself off. I had to to do a battery pull before getting it back on. When it came up, it registered immediately as having 20% not 0% battery.

    I've gotten much improved service after that, but it still makes me wonder if I shouldn't try it again.

    My tip besides quick wear that I needed this - no way did I believe that I really could charge from 40% to 100% in about 15 minutes.
  8. themuffinman75

    themuffinman75 Well-Known Member

    Lithium Ion batteries are not design to be completely drained like that and could potentially cause more harm than good. Li-ion batteries do not have the same memory effect of older nickel based batteries. So I say wipe your battery stats, turn the phone off then charge completely.
  9. jerofld

    jerofld Fixing stuff is not easy VIP Member

    Most batteries have internal controlling circuits that will shut down the cell if it drops below a certain threshold. The evo's battery appears to have that type of circuitry installed in the cell. Letting the phone die is not going to hurt anything, unless you use a cheap third party cell that may not have this safety feature. This is because the cell is programmed to protect itself. Not just from reuced battery life, but thermal runaway. If you completely discharge a cell (below 3 volts), then charge it up, you increase the chance of an 'event'. So that is why each cell has that safeguard on them. Increased battery endurance is just a side benefit.
    themuffinman75 and EarlyMon like this.
  10. EarlyMon

    EarlyMon The PearlyMon Moderator

    I had wondered about that with these batteries - I was worried about tube deformation within the battery, but decided I'd Guinea Pig it.

    This makes my reserve power explanation make sense.
    themuffinman75 likes this.
  11. z50king

    z50king Well-Known Member

    LiIon batteries are very stable when kept anywhere above ~3.0 volts. The stock batteries have a chip inside that won't let them ever get this low with the phone powered on. But if it's left to drain for a few months at room temperature or above it will drain down past this and start to puff up. If you charge it in this state it will pop the bag its in and will ruin your phone. The internal chip probably cuts it out around 3.6 volts, as the battery really loses power just after it crosses 3.7

    We run LiPo in our rc cars when we race and they are more unstable. I recently drained one to 3.1 volts per cell and it charged up fine right afterward.
    jerofld likes this.

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