These batteries may still have ample capacity

June 14 [Fri], 2013, 16:14
Not all stored battery energy can or should be used on discharge, and some reserve is almost always left behind on purpose after VGP-BPS20A bright the equipment cuts off. There are several reasons for this.

Most cell phones, laptops and other portable devices turn off when the lithium-ion battery reaches 3V/cell on discharge, and at this point the battery has about five percent capacity left. Manufacturers choose this voltage threshold to enable some time before recharging. This grace period can be several months until self-discharge lowers the voltage to about 2.5V/cell, at which point the protection circuit opens. Most packs become unserviceable when this occurs. See How to Awaken Sleeping Li-ion.

A battery on a hybrid car is seldom fully charged or discharged; most operate between 20 to 80 percent state-of-charge. This is the most effective working bandwidth of a battery; it also delivers the longest service life. A deep discharge causes undue stress, and the charge acceptance above 80 percent diminishes. The emphasis on an electric powertrain and industrial applications is to maximize service life PA3634U-1BAS bright rather than optimize runtime, as it is the case with consumer products.

Power tools and medical devices with high current draw tend to push the battery voltage to an early cut-off. This is especially true if one of the cells has a high internal resistance, or if operating at cold temperature. These batteries may still have ample capacity left after the “cut-off;” discharging them with a battery analyzer at a moderate load will often give a residual capacity of 30 percent. Figure 1 illustrates the cut-off voltage graphically.