The old ‘fully charge and discharge’ approach stands as one of the simplest ways to ‘recalibrate’ your Android battery. We’ve warned you in the past about low voltage problems in lithium batteries and the negative impacts of fully draining a battery on its lifespan and the same holds true here. But, if your phone battery is causing you real problems, it’s worth taking the risk.

Method 1

1. Discharge your phone fully until it turns itself off.

2. Turn it on again and let it turn itself off.

3. Plug your phone into a charger and, without turning it on, let it charge until the on-screen or LED indicator says 100 percent.

4. Unplug your charger.

5. Turn your phone on. It’s likely that the battery indicator won’t say 100 percent, so plug the charger back in (leave your phone on) and continue charging until it says 100 percent on-screen as well.

6. Unplug your phone and restart it. If it doesn’t say 100 percent, plug the charger back in until it says 100 percent on screen.

7. Repeat this cycle until it says 100 percent (or as close as you think it’s going to get) when you start it up without it being plugged in.

8. Now, let your battery discharge all the way down to 0 percent and let your phone turn off again.

9. Fully charge the battery one more time without interruption and you should have reset the Android system’s battery percentage.

Remember that it is not recommended to perform this process regularly. Even when your battery is so dead your phone won’t even turn on, your battery still has enough reserve charge to avoid system damage. But you don’t want to poke the tiger with a stick. Perform this process once every three months at the most. If it is required more often than that, you have bigger problems at hand.

Modern phones use lithium batteries. It is important that these are not overcharged because this degrades the batteries by forming deposits of metallic lithium. However all modern phones will automatically stop charging as soon as the battery reaches 100%. So there is no danger associated with leaving the charger connected.

If you leave the charger connected the phone will go into a cycle of:

  1. stop charging at 100%
  2. run on the phone battery till the level drops to 9x% (the value of x depends on the phone)
  3. start charging again
  4. go back to step 1

However with modern batteries this won’t have any effect on the battery life. I suspect the warning is just a throwback to the days when this sort of incremental charging could reduce battery life. Lithium batteries generally shouldn’t be stored for long periods at 100% – that’s why when you get a new phone the manufacturer will have charged the battery to around 50%. So I suppose you would reduce battery life if you left it on the charger for weeks at a time.

How do I dispose of a swollen cell phone battery?

How to Remove and Dispose of a Swollen Battery

Although lithium-ion batteries generally don’t fail catastrophically and hurt anyone, you still need to treat them with the kind of respect could-explode-and-burn-you objects deserve.

Do Not Charge or Use the Device

Once you notice the battery is swollen or compromised in any way, you should immediately stop using the device. Turn the power off, and above all else, do not charge the device. Once the battery has reached such a point of failure that the battery is swollen, you must assume that all safety mechanisms in the battery are offline. Charging a swollen battery is literally asking for it to turn into an exploding ball of noxious flammable gas right in your living room.

Remove the Battery

When it comes to removing the battery, there is one very important rule: don’t further compound the problem by compressing, distressing, or compromising the outer casing of the battery. If you puncture the swollen battery, you’re in for a bad time as the compounds inside will react with the oxygen and moisture in the air.

If your device is user-serviceable and you can easily open the case or a service panel to remove the battery, then doing so is in your best interest: it will prevent the expanding battery from (further) damaging your device and it will prevent any sharp edges inside the battery compartment from piercing the protective layer around the battery.

Once you have removed the battery, you should do two things immediately. First, insulate the contacts of the battery (if exposed) with a piece of electrical tape. The last thing you want is for something to short the terminals out. Second, store the battery in a dry cool place away from flammable things until you can safely transport it to a disposal facility.

If your device is not user-serviceable, and you can’t easily remove the battery, then you should take the device to a service location, specialty battery shop, or an authorized battery recycler (see below). There you should find someone with the tools/skills to help open your device and remove the damaged battery.

The same general rules apply even when you can’t remove the battery yourself: take the whole device and store it in a dry cool place to minimize any further degradation of the battery cells and keep it away from anything flammable.