What % of battery to discharge to?

Discussion in 'iPad Pro Forum' started by Padcatt, Oct 18, 2019.

  1. Padcatt

    Padcatt
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    My understanding is that Apple recommends a full discharging and recharging of the iPad pro model once per month. I believe that I read that, other than this once/month discharging, we should never take the battery down too low, and I’m not clear on what that percent of battery charge is.

    10%?
     
  2. twerppoet

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    Mostly you don’t need to worry about it. The recommended full discharge/charge is to calibrate the percent charge meter. It does not have a significant effect on battery health. I believe the instructions actually say below 10%, not full discharge, then a full uninterrupted charge to 100%.

    There is some talk about not leaving the iPad on the charger all the time, and other things you can do; however the overall effect on battery life probably isn’t worth the trouble. Mostly, when it comes to battery health Apple has you covered. The battery managment software will prevent damage, and keep your battery healthy.

    While fully discharging is bad, you can’t easily do this by accident. At some point the iPad will shut down automatically (after several low battery warnings). When it does this there is still a safe charge on the iPad. However, letting iPad sit around for a long time with a low battery could result in a true full discharge, and cause damage. If you’re going to store the iPad for an extended period (a few months) I believe the recommendation is a half charge.

    None of this is a guarantee that your battery won’t fail or loose significant capacity. Batteries weaken and fail, not always on schedule.
     
  3. Padcatt

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    Thank you, this is excellent information. When the iPad Pro’s battery finally dies, does this render the iPad crippled, whether plugged into the charger or not?
     
  4. scifan57

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    If the battery is fully discharged and won’t take any charge, the iPad won’t work even if plugged into the charger. If you have important data on the iPad that hasn’t been backed up you’ll have to get a battery replacement to get it working again.
     
  5. Padcatt

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    Thank you, scifan57...good to know. Is there a technical reason that necessitates this?
     
  6. giradman

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    Hi Padcatt - you've already received excellent information, but some more detail may help your understanding; a Li-Ion battery's physical state depends on a number of factors, but most importantly its 'Cycle Count' and 'Battery Health' - Apple in its (mis-)wisdom does not provide these values in iPadOS nor allow third party developers to add these features to their battery apps (note iPhone iOS does have a 'Battery Health' indicator in Settings).

    'Cycle Count' is the number of TOTAL recharges, i.e. going from 100% to < 10% followed by a COMPLETE recharging (in one or multiple partial stages), while 'Battery Health' represents a percentage ratio of current over design capacity, which decreases w/ battery age. Apple claims that its iDevice batteries at 500 cycle counts should maintain 80% battery health the last time I checked. Now if you have a Mac computer, Coconut Battery is an app that can provide these values when an iDevice is cabled to the computer. As an example, see the pic below - my iPad Pro (battery a year old) - my cycle count is 130 and battery health 98.9% (i.e. 7728/7812 mAh). Dave :)
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    Screen Shot 2019-10-19 at 12.23.34 PM.png
     
  7. Padcatt

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    Is it bad practice, or even harmful when using an iPad which is charging, regardless of what the battery % was when the charging began?

    So, if I take it down to 10%, then plug in the charger, is it ok for me to use the iPad as it charges?
     
  8. scifan57

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    It won’t cause any harm to use the iPad while charging but charging will take longer than if you weren’t using it.
     
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  9. giradman

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    Padcatt - not sure which iPad Pro you own, especially regarding the power port, i.e. lightning vs. USB-C; but I have the newest iPad Pro w/ the USB-C port which allows PD (Power Delivery) charging supplying a higher wattage and much quicker charge time - when I bought my Pro about a year ago, also purchased several PD adapters (for home & travel) - the one I use at home (from Amazon) provides 18W of power on the PD output port. Dave :)
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    Screen Shot 2019-10-20 at 12.39.08 PM.png
     
    #9 giradman, Oct 20, 2019
    Last edited: Nov 5, 2019

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