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Microchip announced the expansion of its analog power-management family with the MCP73831 battery charger, a fully-integrated, single-cell, Li-ion/Li-Polymer charge-management controller. Tiny 500mA linear charge management controller can be powered directly from the USB port. Includes integrated pass transistor, current sense and reverse-discharge protection, the MCP73831 charger reduces the number of components needed for battery-charger designs. Its highly accurate, pre-set voltage regulation (maximum accuracy 0.5 per cent to 0.75 per cent) results in more fully charged batteries and extended battery life. Since the MCP73831 charge-management controller includes a pass transistor, current sense and reverse-discharge protection on a single chip, it reduces the number of system components needed for battery-charger designs, which, added Microchip, lowers overall system costs.

This is a NiCd/Ni-MH charger that can charge with constant current and automatic charge termination when the total voltage for all cells reach the setting voltage.

This simple charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base- emitter voltage of the transistor and the forward voltage drop across the diodes are relatively stable. The charging current is approximately 15mA or 45mA with the switch closed. This suits most 1.5V and 9V rechargeable batteries.

The electric model aircraft and car industries have produced a bewildering array of field chargers for NiCd motor battery packs. These range from simple 6 or 7 cell chargers consisting of a resistor and mechanical timer, to more complex chargers with peak detection, cycling, and the ability to handle 36 cell packs.

This cheap and easy to build NiCd/NiMH Battery Charger is suitable for automatically charging a wide range of batteries for many applications. Proper chargers are usually expensive and cheap chargers supplied with the original equipment often incorrectly charge the cells and dramatically shorten their life.

Portable USB Charger is a device that will charge things like Ipods, PDAs, that accepts charge from a USB port. It runs off a 9-V battery, and through the simple circuit, out comes a regulated 5-V perfect for a USB port. Portable USB chargers will always be handy, lets face it these days every gadget around us has USB charging capabilities. This is a very basic and simple project, and cheap too. Maybe its time for you to build your own diy portable USB charger.

This is a Lithium-ion charger for lipo batteries. Circuit schematic shows configuration for charging single 3.7V lipo battery but voltage can be set to charge several batteries in series. Lipo charger sets a current limit with the LM317, and 1 resistor, and the voltage limit with the TL431, and 2 resistors. 1K resistor is needed to let the TL431 decrease the LM317 current, and to provide the necessary current to the TL431. The optional Schottky diode at the output will prevent current flowing back from battery to the charger circuit when power is disconnected, and reverse biasing of the LM317. Power supply with more than 3V above output voltage is required.

This is a solar panel battery charger schematic for AA and AAA rechargeable batteries. A small solar panel makes an excellent battery charger for AA and AAA rechargeable batteries. Only a few components are required and construction is very simple making this a perfect first renewable energy project. Rechargeable AA and AAA batteries have a voltage of around 1.2 Volts when fully charged. Therefore 2 in series gives a total of 2.4 Volts, 4 in series 4.8 Volts. Common solar panel output voltages are 3 Volts for example the 3V 100ma solar panels, and 6 volts - perfect for charging 2 or 4 batteries respectively. Solar panels should be well adapted to the battery to be charged or the battery may be overcharged. If you want to charge batteries with different capacities, then you need to change the solar panels. Since this is a simple solar battery charger that does not automatically turn off when the battery is full. So we need to maintain the charging current is low enough that will not damage the battery even when they are fully charged. An LM317T voltage regulator chip that can be used with a suitable resistor to regulate current. See solar AA battery charger

This instructable will show you how to make your own solar battery charger from very simple components. It is taken from my documentation provided with a kit I supply - you should easily be able to source the same components yourself of course.

This is a simple to build charger for single 3.7V lipo battery. The heart of the charger is TL431 shunt regulator that controls the incoming current. Charger comes with a convenient charging LED indicator. As charging current goes down so does the intensity of the LED.