Many devices will also be able to tell you how much operating time the current battery percentage will give you. This can be helpful if you are planning when you need to charge your device. [3] X Research source

When your device is turned off during charging, the lithium-ion battery is able to reach the set voltage threshold without being hindered. Overall, if the device is still left on, the lithium-ion battery is prevented from charging as it should. Don’t worry too much if you cannot have your device switched off while it is charging. Although turning the device off is ideal, it won’t have a significant, negative effect on the battery if it is left on.

Sometimes letting your device charge fully is unavoidable. Don’t worry about it if it does happen, but try to reduce how often it does and get into a routine of not letting it charge fully. You can also download apps which will set a charging limit on your device. These are particularly useful for smartphones and tablets.

Shallow discharges are better for the long-term health of the lithium-ion battery. This is because it helps to maximize the finite number of charge/discharge cycles that the battery has. This means that shallow discharges will help to maintain the lifespan of the battery. [9] X Research source Ideally, never let your battery fall below 10%. [10] X Expert Source Garnik OvsepyanComputer Specialist Expert Interview. 1 July 2021.

Lithium-ion batteries do not tolerate overcharging well. Keeping your device charging once the battery has reached 100% degrades its lifespan. [12] X Research source

If the smart battery is giving inaccurate readings, this means that it will be more difficult for you to plan when to next charge your device. This can have a greater negative impact on the lifespan of your lithium-ion battery than letting it drop to 0% once per month.

It is possible to charge a lithium-ion battery at below freezing temperatures, however, due to the nature of the battery it takes a long time to do so.

The best temperature for storing the battery and maintaining its lifespan is at 59 °F (15 °C). However, technically lithium-ion batteries can be stored at −40–122 °F (−40–50 °C). [16] X Research source