This week we’ll send a Charger Alkaline Batteries PCB  to two readers. So if you want this PCB you can fill into the coments.  Magazine Emiter has described how to build this project with full details, so if you want this magazine you can buy from here.     Rules: Yes, we’ll mail it anywhere [...]

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 [...]

This battery charger automatically starts the charging procedure when battery voltage drops below a certain predefined value and stops after the voltage has risen above the maximum allowed value. Setup can’t be easier, just connect two alligator clips to battery terminals and plug the device in mains. This way it can stay connected for months [...]

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. This ‘intelligent’ charger was designed for high current and rapid [...]

This is a automatic battery charger, after completing the charge it turns off automatically. It runs on AC power but you can also run it with DC power. Its not my idea or my invention, I got it from net. After understanding the circuit I built it and it works fine. So try to built [...]

Lithium-Ion cells require a constant voltage, current limited charge. The voltage must be accurately limited to 4.2V, as higher voltage reduces cell life. This circuit is designed to meet these requirements using standard components. Source: bhabbott

The circuit consists of two parts, a constant current generator using a PNP power transistor (Q2), and a peak-detecting shutoff circuit using a high-gain opamp (IC1). To start the charge cycle, switch SW1 is momentarily closed, causing C1 to discharge. As IC1′s inverting input is now higher than its non-inverting input, its output goes low, [...]

Source: Stefan’s Electronics

Most off-the-shelf car battery chargers cannot not be left connected to the battery for long periods of time as over-charging and consequent battery damage will occur. This add-on circuit is placed in series with the battery being charged and is powered by the battery itself. In effect, the circuit uses a high-current Mosfet to control [...]

Portable iPod charger that you can use while away from your computer. The circuit is based around an MC34063 switchmode regulator. This has high efficiency so that there is very little heat produced inside the box, even when delivering its maximum output current. The circuit is more complicated than if we used a 7805 3-terminal [...]

Parts:R1 33 ohm D1 1N4007R2 10 kohm U1 B250C1000RR3, R8 5,6 kohm T1, T2, T3 BC548BR4, R7 100 kohm ZD 6,8 V, Zener.R5 2,7 Mohm LED1 ?ervená / red, standardR6 680 kohm LED2 zelená / green, 2 mAR9 47 kohm IC1 HEF4541C1 100 mikroF/25 V(35 V) C2 1 mikroF,clips from old batteryC3 100 pFC4 100 [...]