The universal battery charger’s output voltage is adjustable and regulated, and has an ajustable constant-current charging circut that makes it easy to use to use with most NiCad batteries. The charger can charge a single cell or a number of series-connected cells up to a maximum of 18V. continue reading…

This 12V battery charger circuit is a high-performance charger for gelled-electrolyte lead-acid batteries. This charger quickly recharges the battery and shuts off at full charge. Initially, charging current is limited to 2A. As the battery voltage rises, current to the battery decreases, and when the current has decreased to 150mA, the charger switches to a lower float voltage, which prevents overcharge. When the start switch is pushed the output of the charger goes to 14.5V.
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This circuit delivers an initial voltage of 2.5V per cell to rapidly charge a car battery. The charging current decreases as the battery charges and when the current drops to 180 mA the charging circuit reduces the output voltage to 2.35 V per cell, leaving the battery in a fully charged state. This lower voltage prevents the battery from overcharching, which will shorten its life.
The LM301A compares the voltage drop across R1 with a 18 mV reference set by R2. The comparator’s output controls the voltage regulator, forcing it to produce the lower float voltage when the battery-charging current, passing through R1, drops bellow 180 mA. continue reading…