The golden rule is to keep your battery topped up somewhere between 30% and 90% most of the time. Top it up when it drops below 50%, but unplug it before it hits 100%. For this reason, you might want to reconsider leaving it plugged in overnight.
Pushing in the last charge from 80-100% causes a lithium-ion battery to age faster.
Giving your phone a full recharge is not fatal for a phone battery, and it seems almost counter-intuitive not to do so, but giving it a full recharge every time you charge it will shorten its lifespan. Likewise, at the other end of the scale, avoid allowing your phone battery to get below 20% . Lithium-ion batteries don’t feel good about going too far below the 20% mark. Instead, see the extra 20% “at the bottom” as a buffer for demanding days, but on weekdays start charging when the warning for Low Battery level appears.
In short, lithium-ion batteries thrive best in the middle. Don’t get a low battery percentage, but also not too high.
Should I charge my phone battery to 100%?
No, or at least not every time you charge it. Some people recommend that you do a full zero to 100% battery recharge (a “charge cycle”) once a month – as this re-calibrates the battery, which is a bit like restarting your computer.
But others disregard this as a myth for current lithium-ion batteries in phones.
To keep your long-term battery life in good health, frequent, small charges are better than full recharging.
Can I use any phone charger?
Where possible use the charger that came with your phone, as it is sure to have the correct rating. Or make sure that a third-party charger is approved by your phone’s manufacturer. Cheap alternatives from Amazon or eBay may harm your phone, and there have been several reported cases of cheap chargers actually catching on fire.
That said, your phone should draw only the power that it needs from a USB charger.
Storing battery tips
Don’t leave a lithium battery lying around too long at 0% – if you’re not using it for a while, leave it with around 50% charge.
If you are going to put the phone away for a long time, first charge it to somewhere between 40-80% and then turn off the phone.
You’ll find the battery will drain between 5% and 10% each month, and if you let it discharge completely it might become incapable of holding a charge at all. That’s probably why an old phone’s battery life is so much worse after a few months in a drawer, even when it hasn’t been used.