Laptop batteries differ from other types of batteries in that they provide a relatively short service life and are expensive to replace. In this article We look into the possibilities of tesing and repairing them, and also we will provide some information of batteries.

In today’s world, all of the laptop batteryis are with li-ion cells, like the Dell Inspiron 6400 battery(http://www.papatek.com/Dell-Battery/Dell-Inspiron-6400-battery.html) has nine li-ion cells. Under good conditions, Lithium-ion provides 300 to 500 discharge/charge cycles or 2 to 3 years of service from the time the battery leaves the production line. The capacity loss occurs through increased internal resistance caused by cell oxidation. Eventually the resistance reaches a point where the battery can no longer deliver the needed energy although the energy may still be present in the battery. There are no remedies to restore the capacity when worn out. Heating the battery will momentarily improve the performance.

The basic knowlege you should know in obtaining quick test readings is measuring the battery’s internal resistance, often referred to as impedance. Internal resistance measurements take only a few seconds to complete and provide a reasonably accurate indication of the battery’s condition, especially if a reference reading from a good battery is available for comparison. To measure the impedance, a battery must be at least 50 percent charged. An empty or nearly empty battery exhibits a high internal resistance. As the battery reaches 50 percent SoC, the resistance drops, then increases again towards full discharge or full charge. Figure 13-1 shows the typical internal resistance curve of a NiMH as a function of charge. Note the decrease of impedance after the battery has rested for a while. To obtain accurate results, allow the battery to rest after discharge and charge.

Laptop batteries can be repaired but such work only makes economical sense for smaller operators. The success rate varies with battery type. One must remember that the ’smart’ battery consists of two parts, the chemical cells and the digital circuit. In some cases, the chemical part can be fully restored but the fuel gauge may become inaccurate or other data may get corrupted.

Anyone attempting to repair SMBus battery must be aware of some non-compliance in the SBS forum. Unlike other tightly regulated standards, the SMBus protocol allows some variations. This may cause problems with existing chargers and the SMBus battery should be checked for compatibility before use. The need to test and approve the marriage between a specific battery and charger is unfortunate, given the fact that the SMBus battery is being promoted as being universal. Ironically, by adding more features to the SMBus charger and the battery, the higher are the likelihood of incompatibilities.