AA Battery Charger

The AA battery charger is also known as penlight battery charger, since penlight is the colloquial name for the AA battery. The name AA battery charger can be pronounced either “double ay battery charger” or “ay-ay battery charger”.

A battery charger is an appliance capable of energizing a battery. The AA battery charger works by forcing an electric current through the rechargeable AA battery. The exact charge current in a battery charger must always be determined by the capacity and technology of the batteries that it will be charging.

The charge current in an AA battery charger will therefore be less suitable in a 12 V car battery charger or mobile phone battery charger, and vice versa.

The most basic form of AA battery charger consists of a power source capable of providing constant direct current power to the batteries. This type of basic AA battery charge will not adjust its output according to time or the charge on the battery. This type of AA battery charger is popular since it is inexpensive, but it will often need quite a lot of time to recharge the batteries. The slow charge pace is a way of trying to prevent severe overcharging of the batteries. Despite this preventive measure, your batteries will become damaged or even ruined if you leave them in this type of AA battery charger for too long. Keeping track of the time and never forgetting your batteries in the AA battery charger is therefore a must.      

If you want a safer form of AA battery charger you can purchase one with a timer. In this type of AA battery charger, the output is turned off after a pre-determined time to prevent overcharging. This type of timer was very popular for NiCd AA batteries in the 1990’s. A problem with this type of charger, and one of the reasons for its currently low popularity, is that it does not detect the capacity of the individual AA battery that is placed within it. You can often purchase this type of AA battery charger as a bundle together with four or six rechargeable AA batteries.  If you use other AA batteries with a higher capacity, they will not become fully charged since the timer will turn off the output prematurely. If you use AA batteries of a lower capacity they will be over-charged and possibly damaged. Since the manufacturers of AA batteries constantly strive to create batteries with higher and higher capacity, an old timer charger will be quite useless since it will never fully recharge your new, high capacity batteries.

The so called “intelligent” AA battery charger can detect the voltage of the battery, the temperature and/or the time, and use this information to determine the ideal charge current for each particular moment. When the voltage, temperature and/or time tell the intelligent AA battery charger that the battery is fully charged, the charger will turn of itself.

If you know that you frequently need to rapidly recharge your batteries, you can purchase a so called “15 minute AA battery charger”. This type of AA battery charger is also marketed as super fast chargers or rapid chargers. It is common for the fast AA battery charger to be equipped with a fan to cool of the device and keep the temperature of the batteries down.