I am considering purchasing a new Google Pixel 3XL Android phone, primarily for photography. I don't believe those phones have been manufactured for 2-3 years, so I am concerned about the battery health. If the phone has been sitting in a box for 2 years with 0% charge, my understanding is that it's likely the battery will not function well.

For this reason, I'm wondering: What is the approximate battery discharge rate of Google Pixel 3XL Android phones when turned off?

(Also, if anyone happens to know how approximately much battery charge was present when the phones were placed in their box, that will be helpful.)

1 Answer 1


The answer starts from what you asked towards the end of your question.

  1. Li-ion battery's are charged to around 40% while storing. That's about the charge level (give or take few % points) you'd see when you take a phone out of box for first time. Reason

Lithium-ion must be stored in a charged state, ideally at 40 percent. This prevents the battery from dropping below 2.50V/cell, triggering sleep mode.

Sleep mode is a protective mechanism to prevent deep discharge and you can't charge the battery conventionally when it enters that mode.

  1. But batteries do self discharge and the typical rate of Li-ion batteries is about 2% per month (Table 3). But this does not mean you get a fully discharged battery say after 2 years. That's because

There is virtually no self-discharge below about 4.0V at 20°C (68°F); storing at 3.7V yields amazing longevity for most Li-ion systems

  1. But yes, your battery would suffer a capacity loss as you can see in Table 2 of link quoted in above point. If you can get a new battery from OEM, which is manufactured recently, this risk can be mitigated and you can use it for long. But if your use case is only photography, I guess you need not change battery at all.

This is generally applicable to all Android devices and your specific model should not be an exception.

  • 1
    Thank you so much. That is all excellent information! A comment then a question: Comment: It's unsettling that the site you found states ~2%/mo, but this other site states 10%/mo for Li-ion: batteryeducation.com/2012/10/battery-self-discharge-rates.html Question: In item 3, you mentioned "Table 3". Did you mean Table 2? If so, and we extrapolate the data from Table 2 linearly (any idea if linear would be correct curve for extrapolation?), that would mean a 3 year old battery stored with an initial charge of 40% at 25C would have ~88% capacity; if stored at 30C, ~77% capacity. May 12, 2021 at 8:14
  • Thanks. There is lot of conflicting information on the net on these aspects. That's why I prefer Battery University as it has a series of articles which are not internally conflicting - to address your comment //Coming to your Question in comment, it isn't linear. AFAIK there is nothing like negative storage - any battery is technically EoL of it's capacity is down to 80% of rated capacity. Of course it can still be used for a long time, only charging needs to be frequent, to a point is reached where it needs to be on charge to be used // Yes I meant Table 2, fixed typo, thanks catching that
    – beeshyams
    May 12, 2021 at 9:08
  • Thanks. You mentioned that any battery is technically EOL at 80% of rated capacity. Does Google replace them for free under warranty if they drop below that level? May 13, 2021 at 14:45
  • Of course NO... Batteries aren't covered in warranty AFAIK
    – beeshyams
    May 13, 2021 at 15:20
  • Of course not. LOL. It reminds me of crappy vehicle warranties that pretty much only cover components within the drivetrain and very little else. May 13, 2021 at 20:23

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