Overcharging: The Grim Reaper of Rechargeable Battery Life
Overcharging
Overcharging is a very important thing to be wary of when charging whatever rechargeable battery you are using. When you leave a battery charging for a long period of time (overnight, for example) the battery charges up to 100%. But what happens when the battery reaches 100% in the middle of the night and is left plugged in until morning? Well, to understand what happens, you must know something a tiny bit about how a battery works.
When a rechargeable battery is in use, an electrical current is flowing from the negative cathode to the positive anode. This current is made up of electrons, extremely tiny electrical particles. As more and more electrons flow from the cathode to the anode while the battery is in use, it gradually loses its charge. This whole process is fueled by a chemical reaction that takes place within the battery.
In order to recharge the battery, the chemical reaction that produces this flow of electrons must be reversed. To do this, we use chargers that connect the battery to an electrical outlet. Over time, the reaction is reversed and charge is restored to the battery. One byproduct of this process is heat.
This leads right back to our original question... what happens when a battery is left for too long in a charger? The answer is that the heat that is produced from leaving the battery in the charger after the charging process is complete causes the chemical substances inside the battery to degrade, leaving less fuel for the chemical reaction that produces current.
