How do you fix an overcharged battery?

Answer 1

That largely depends on what kind of battery you are talking about. However, most rechargeable batteries will likely be ruined by overcharging. If you are referring to a car battery, it cannot be repaired, except to be rebuilt.

Simply put, when a battery is overcharged, the plates inside the battery lose oxides. That, and overheating, also causes the electrolyte solution to lose water/moisture. This permanently reduces capacity and leaves portions of the plates exposed to further oxidation. Then, it's all downhill from there! Spiral cell and/or gel filled batteries (such as Optima) are affected somewhat differently, but the effects of overcharging are even worse for them.

If your battery has been overcharged, or you suspect any problems, have it tested. Most auto parts suppliers (AutoZone, for example) will test your battery for free. While the tester cannot show the internal condition of the battery, it does effectively reveal its overall condition by testing voltage, amperage, discharge rate, and recovery time. These factors together tell whether or not the battery needs to be charged, or simply cannot take/hold a charge anymore.

**Disclaimer**: This is the general rule of thumb. There are battery re-conditioners on the market that can, in rare cases, help save a battery if the damage is caught early and minimized. However, the cost of these devices usually offsets the slim chances that it might work. Also, they're usually more expensive than simply replacing the damaged "might-be-okay" battery with a brand-new one.

Answer 2

Occasional over-charging won't hurt the phone... simply discharge the battery completely before re-charging.