Modern smartphones have optimized batteries that will stop drawing power once they reach 100 percent. However, when you leave it on the charger, the phone will inevitably lose a little bit of power as it sits there because that's just what batteries do.
Likewise, 100% is not the maximum the battery can store; it stops charging slightly short of maximum to prevent overcharging. The worst thing you can do is drain the battery to 0%, then not charge it immediately.
Plug your phone in to charge when you go to bed and leave it plugged in all night every night. You cannot overcharge an iPhone. This is the recommended way to maintain the health of your battery.
The answer is, theoretically, yes – you can overcharge your iPhone battery. However, it's highly unlikely to occur, and the iPhone is designed to prevent this from happening. All modern smartphones are equipped with lithium-ion batteries, and these batteries work differently than traditional batteries.
Bottom line - keep phone charges out of bed!
The National Fire Protection Association (NFPA) advises, "Smartphones should be charged in locations that allow for adequate ventilation so they do not overheat. Charging them under a pillow, on a bed or couch doesn't allow for the necessary airflow."
Yes, in fact, most people do just that as it is a convenient time to charge. The battery cannot be over-charged. Check this link...
As a result of too high a charge voltage excessive current will flow into the battery, after the battery has reached full charge. This will cause decomposition of the water in the electrolyte and premature aging. At high rates of overcharge a battery will progressively heat up.
There may not be a noticeable change straight away but if you do this every single night, you may see your battery degrade over time. Therefore, charging your phone overnight isn't necessarily bad but you should not do it consistently if you want to get the best out of your battery.
As a good practice, you should avoid charging your iPhone to 100% all the time and not let it go below 25%. Ideally, keep the battery percent somewhere between 30% and 80% to maintain your iPhone's battery health.
Instead, it will sip power from the battery until it drops to 99% (or thereabouts). The above cycle then simply repeats itself until you unplug the device. Put simply, you can safely charge your devices overnight without having to worry about damaging their internals.
The most common myth about overnight charging is that it can overload your battery. This is simply not true. All smartphones are designed with protective measures that prevent the battery from overcharging once it's full. As soon as the battery reaches 100%, it stops charging.
The correct option is Option C It can overheat.
Therefore, we recommend the following: Do not fully charge or fully discharge your device's battery — charge it to around 50 percent. If you store a device when its battery is fully discharged, the battery could fall into a deep discharge state, which renders it incapable of holding a charge.
Maintain good battery health
It is always recommended by experts to start charging your iPhone when it hits 25 percent. Similarly, only charging the battery up to 85 percent will help the iPhone's battery to maintain good battery health and deliver extended battery life.
Heat Kills Lithium-ion Battery Packs
Don't. Move them to your garage or somewhere you can temper the heat somewhat and reduce the pack temperature. High temperature kills lithium-ion batteries. Want to cut your number of cycles in half, store your packs in the heat fully charged.
The iPhone's charging system and battery are designed to prevent overcharging, so you don't need to worry about it damaging the phone. However, it is recommended to unplug the iPhone once it reaches 100% charge to conserve battery health over time.
Playing games that require a lot of resources, leaving your phone in a hot car, or letting it bake in the sun at the beach. All of these things can overheat your phone and damage the battery in the process.
Shomes recommends charging your iPhone as it needs it. If you go to sleep and it has a 40 or 50 percent charge, leave it. Then charge it some time during the next day when it gets into the red. That way, the battery won't be stressed, and its health will last way longer than it will when overnight charging.
Charging issues
Using your iPhone while it's charging, or charging it with a non-Apple charger that doesn't comply with Apple's safety standards, can cause it to overheat. Wireless charging causes more heat to be produced than using a cable. Solution: Use a quality charger and cable. Switch to a lower-power charger.
Excessive heat can damage the battery's capacity and shorten how long it can power your device on a single charge. Very cold conditions can also impact battery life, but the effects are temporary.
Heat is a battery's enemy. Cold is no friend to batteries either, resulting in a shorter use time, but that is only temporary until your battery warms back up again. Apple says your iPhone can safely run in temperatures of up to 95 degrees Fahrenheit. Beyond that, irreversible damage can occur to the battery.
Frequent overcharging damages your battery because it forces more current into already full cells than they are designed to hold. It also means your iPhone spends most of the night at 100% charge, which is bad for its battery health.
Your battery will stop charging at full charge, but once it drops to 99%, it will need more energy to get back to 100. This is unnecessary and it eats away at your battery's lifespan. If you must go to 100%, unplug your phone from the charger as soon as you hit the max.