DO’s when charging
A random or partial charge is fine. Li-ion doesn't need to be fully full charged
Keep the battery cool, especially when charging
Use manufacturer supplied chargers.
Store at around 50% for long term storage
Avoid battery intensive tasks like gaming when charging
Avoid idle charging
Point on (2) - move it away from heat-generating environments. Recommended to remove bulky cases that trap heat in the device (leather ones) when charging but not required. Try to leave the phone charging on a hard surface instead of on the bed or sofa. Point on (3) - If spare chargers are needed, either buy first-party ones or from name brands that support the charging speeds and standards of your device. Eg. USB-C Power Delivery
DON’T’s when charging
Discharge Li-ion battery to 0%
Charge in very hot places
Use sketchy chargers, cheap at too good to be true prices
Store at 0% for long term storage
Gaming when charging
Continue charging for a long time at 100%
Point on (6) - Overnight charging before sleep is one example, but don’t sweat it if you can’t help. An insignificant wear on the battery for a day could be better than having a dead phone when you go to work the next morning.
Descriptive technical section
Read on to understand the science behind the little batteries powering your device. To understand how to boost the battery life on your device, it is important to understand some basics behind the chemistry of how smartphone batteries work. Moreover, it is also vital to understand the difference between battery life and battery capacity.
Battery life means the actual lifespan of the battery before it degrades to a high voltage due to high internal resistance, that is no longer optimal for use. Do note that battery life is also often loosely used to describe the time it takes for a phone to discharge from 100% to 0%. Battery capacity simply means the actual capacity of which the battery can supply the rated power to operate the device. These two can correlate to each other when the battery degrades.
The batteries in our devices are all made with Lithium-ions, and they generate a charge by facilitating the flow of electrons and lithium ions between the positive and negative electrodes.
To explain it all in Layman terms, when a device is turned on, the anode (negative terminal, high energy state) has a route to discharge electrons to the cathode (positive terminal, lower energy state, usually made of metal like aluminum) and this process generates a current that powers the device. When the battery is recharged, the electricity applied will force the electrons discharged to return, thereby returning the battery to a higher energy state.
A battery performs the best and maintains its optimal life cycle around room temperature (± 10°C at 26°C). Anything close to freezing or significantly higher than room temperature is detrimental to the battery life. I will not delve deeper into how a battery degrades when it is too cold, as more often than not it is physically impossible for that to happen in Malaysia’s weather. Even in the lowest air-conditioning setting of 16C, your device’s battery internal resistance will produce some heat that brings it up somewhat.
At higher temperatures (>45C), if the battery is actively being discharged or being recharged, some interesting chemical reactions happen. The lithium ions crystallize at the endpoint, the carbon structure breaks down or the electrolytes (that facilitate the movement of ions and electrons) start to oxidize. These crucial elements when degraded, they form a layer of junk on the end points.
If kept at room temperatures, all batteries will inevitably degrade when used, albeit at a significantly slower pace. But under high heat, the parasitic reactions that facilitate the degradation of the battery will happen quicker which results in a shorter battery life.
These small occurrences will build up and gradually lead to a lower capacity to store electrons as the amount of free flowing ions in the anode and cathode has decreased. The degradation of the anode and cathodes are irreversible and permanent. So, keeping the charging and operating temperatures low can help in prolonging the battery life.
TL;DR – high heat increases the speed of physical degradation of the battery.
With a reduced battery capacity, the actual battery life of the battery reduces too. This is because when the battery physically starts to degrade, the voltage of the battery will gradually increase to compensate for the higher internal resistance resulted from the parasitic layers of junk on the electrodes. If you remember your high school physics, V=IR, but I (current) stays constant here so the voltage has to increase proportionally to the internal resistance of the battery.
After a few years of this so-called self-fulfilling cycle of degradation the battery will eventually reach voltage levels too high to use when it is rapidly degrading and effectively "die". This happens when the battery’s circuit protection mechanism kicks in and stop you from charging and discharging the battery (powering the device) so the unstably high voltage won’t damage the device.
Hence, use your manufacturer supplied chargers as they are the ones that designed and manufactured your device. You can even use a QI wireless charger to charge your device as it is convenient and charges it at safer speeds at lower wattage unlike the other super fast charging standards. You may get your Samsung wireless charger here that can work with other devices that support the QI wireless charging standard.