project_report.docxWhen we charge a battery after his charging capacity than the temperature of the battery and the pressure of the oxygen in the battery increases. Due to this the life time of the battery will decreases. As we minimum charge the battery ,It will increase the life time of the battery. Here this project is based on the principle of Voltage Cut Off. It will turn off the charger when the battery is charged 80% of his maximum capacity. Rechargeable nickel-cadmium (NiCd) batteries are widely used in consumer electronics because of their high energy density, long life, and low self-discharge rate. Standard NiCd cells can be charged at different rates: a fast charge with high current, or overnight with low current. Regardless of the charge speed, a steady current should be provided to the battery during charging. Also, more energy must be supplied to the battery than its actual capacity to compensate for energy loss during charging. The cheapest and safest way to charge a NiCd battery is to charge at 10% of its rated capacity per hour for 16 hours. The battery pack used contained two AA-size 1200-mAh NiCd cells, so the battery should be charged with 120-mA current. NiCd chemistry-based batteries have very similar characteristics from the point of view of charging and discharging properties. The typical midpoint voltage is equal to 1.2 V. Typical discharge voltage is 0.9 V (75 percent of 1.2 V). These batteries are typically charged with a constant current and allow the battery to rise to the charged level. Detecting when the battery is charged is accomplished by various methods. Another method of the end-of-charge detection is temperature per time growth. Both methods are associated with the same internal effect of growing internal pressure. The result is that we can reliably monitor the –ΔV to detect end-of-charge state. Ni–Cd batteries can be charged at several different rates, depending on how the cell was manufactured. The charge rate is measured based on the percentage of the amp-hour capacity the battery is fed as a steadycurrent over the duration of the charge.