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This small circuit was developed to monitor the battery in a model hovercraft. The lift in the model is produced by an electric motor driving a fan. To avoid the possibility of discharging the rechargeable battery pack too deeply, the design lights a conspicuous LED mounted on the model when a preset threshold voltage is reached. The circuit only uses a few components, which helps keep the total weight of the model down. The circuit connects to the model only across the two points where the voltage to be monitored can be measured. These also supply power to the circuit. The best place to connect the circuit is not at the battery terminals, but rather at the motor connections. The circuit is suitable for use with nominal battery voltages of 4.8 V to 9.6 V (four to eight 1.2 V cells). For example, if there are six cells in the battery, its nominal terminal voltage will be 7.2 V. A discharge threshold voltage of around 1 V per cell is appropriate, which means that for six cells the thresh...

A small electronic switch that connects a battery to the equipment for a certain amount of time when a push-button is momentarily pressed. And we have also taken the ambient light level into account; when it is dark you won’t be able to read the display so it is only logical to turn the switch off, even if the time delay hasn’t passed yet. The circuit is quite straightforward. For the actual switch we’re using a well-known MOSFET, the BS170. A MOSFET (T2 in the circuit) used in this configuration doesn’t need a current to make it conduct (just a voltage), which makes the circuit very efficient. When the battery is connected to the battery saver circuit for the first time, capacitor C2 provides the gate of the MOSFET with a positive voltage, which causes T2 to conduct and hence connect the load (on the 9 V output) to the battery (BT1). C2 is slowly charged up via R3 (i.e. the voltage across C2 increases). Battery Saver Circuit Diagram This causes the voltage at the gate to drop and eve...

Normally mobile batteries have a lifespan of 2-5 years under normal usage. But then we have to replace them. Nowadays there are cheap replacement batteries which cost no more than 1$. But these low cost batteries run only 6-12 months. What to do with the used batteries, which can’t be reused in mobiles? Well, easy solution is to use the batteries in a circuit that requires less current. We can use them for LED lighting. Do you have old unusable Mobile battery? Normally mobile batteries have a lifespan of 2-5 years under normal usage. But then we have to replace them. Nowadays there are cheap replacement batteries which cost no more than 1$. But these low cost batteries run only 6-12 months. What to do with the used batteries, which can’t be reused in mobiles? Well, easy solution is to use the batteries in a circuit that requires less current. We can use them for LED lighting. Thus your automatic lighting emergency light is ready which runs by your waste Mobile Battery.  ...

Ultra-low current drawing 1.5V battery supply This circuit is usable as a Night Lamp when a wall mains socket is not available to plug-in an ever running small neon lamp device. In order to ensure minimum battery consumption, one 1.5V cell is used, and a simple voltage doubler drives a pulsating ultra-bright LED: current drawing is less than 500µA. An optional Photo resistor will switch-off the circuit in daylight or when room lamps illuminate, allowing further current economy.    This device will run for about 3 months continuously on an ordinary AA sized cell or for around 6 months on an alkaline type cell but, adding the Photo resistor circuitry, running time will be doubled or, very likely, triplicated.   Parts: R1,R2___________1M 1/4WResistors  R3_____________47K 1/4W Resistor  R4____________Photo resistor C1____________100nF 63V Polyester  Capacitor C2____________220µF 25V Electrolytic Capacitor  D1______________LED Red 10mm. Ultra-bright D...

This is a circuit solar charger via USB cable emergency , it is an alternative circuit that uses solar cell and LM317 to regulate and make a recharge via USB for electronic equipment that can be IPODs , cell phones , MP3 , tablets , etc. .   The simplicity of the circuit can be noted that he does not have much appeal, but it's enough to make a simple battery charge . The Solar Cell should be 12v current should be enough for loading , 10 % of the batteries .   Battery Charger Circuit using Solar Cell Circuit Diagram

This universal battery charger is based on LM317 and has an adjustable regulated output voltage and also has an adjustable constant-current charging circuit that makes it suitable to use for charging most NiCad batteries and some other types of batteries . This LM317 universal battery charger can charge a single cell or a number of series-connected cells up to a maximum voltage of 18 V. This universal battery charger circuit use just some common electronic components like LM317 regulator , operational amplifier and some 2n3055 power transistors .2n3055 power transistors Q1 and Q2 are connected as series regulators to control the battery charger's out¬put voltage and charge-current rate. The LM317 used as an adjustable voltage regulator supplies the drive signal to the bases of power transistors Q1 and Q2. By turning the potentiometer R9 the output-voltage level will be modified. A current-sampling resistor, R8 (a 0.1-fi, 5-W unit), connected between the negative output lead and cir...

The project produces a battery charger that may be used to charge NiMH, Li-Ion, NiCad, sealed lead acid, and rechargeable alkaline batteries. There are two channels that the charger imposes which can charge two different batteries at a time at up to 2A each while channel A can be used as a discharger alternatively. All necessary parameters are allowed to be set by a 2x16 LCD display with a 5-key keypad while displaying charging/discharging values including mAH when complete. A fixed voltage, current limited output, fixed current, voltage limited output, and a variable PWM output are provided as a bonus. The brain of the circuit is performed by an ATmega32 microcontroller that runs at 16MHz. In the charging circuit, the inductor/capacitor pair are optimized for a 16kHz pulse width modulated signal and provide and provide a smooth DC output. The raw signal is compensated in software for the drop across the current measurement resistor and lead wires while and the voltage input needs to b...

For any complete energy-harvesting system designed to provide power to anything but small, short-duration loads, storage batteries represent a necessary but significant portion of the initial expense. The cost of batteries over the lifetime of the system can have an even larger impact if care is not taken to maximize the useful life of the battery component. What’s more, if unit growth continues for photovoltaic and other energy-harvesting systems relying on large-capacity storage batteries, designs that fail to maximize battery life could have a negative environmental impact due to the extra material and energy consumption needed to manufacture replacement systems as well as dispose of exhausted units.

A very simple battery charger circuit having reverse polarity indication is shown here.The circuit is based on IC L200 . L200 is a five pin variable voltage voltage regulator IC. The charging circuit can be fed by the DC voltage from a bridge rectifier or center tapped rectifier.Here the IC L200 keeps the charging voltage constant.The charging current is controlled by the parallel combination of the resistors R2 & R3.The POT P1 can be used to adjust the charging current. Battery charger circuit using L200 With Parts list This circuit is designed to charge a 12 V lead acid battery.The transistor t1,diode D3 and LED are used to make a battery reverse indicator.In case the battery is connected in reverse polarity ,the reverse polarity indicator red LED D5 glows.When the charging process is going on the battery charging indicator green LED D4 glows. Notes. The circuit can be assembled on a good quality PCB or common board. The values of R2 & R3 can be obtained from th...

Except for use as a normal Battery Charger , this circuit is perfect to 'constant-charge' a 12-Volt Lead-Acid Battery , like the one in your flight box, and keep it in optimum charged condition. This circuit is not recommended for GEL-TYPE batteries since it draws to much current. The above circuit is a precision voltage source, and contains a temperature sensor with a negative temperature coλficient. Meaning, whenever the surrounding or battery temperature increases the voltage will automatically decrease. Temperature coλficient for this circuit is -8mV per °Celcius. A normal transistor (Q1) is used as a temperature sensor. This Battery Charger is centered around the LM350 integrated, 3-amp, adjustable stabilizer IC. Output voltage can be adjusted with P1 between 13.5 and 14.5 volt. T2 was added to prevent battery discharge via R1 if no power present. P1 can adjust the output voltage between 13.5 and 14.5 volts. R4's value can be adjusted to accommodate a bit larger or s...

Battery Charger in general can be interpreted as a means to recharge the battery charge. Principles of good charger circuit is capable of providing resources to perform effectively charging the battery, efficient and safe. AVR-Based Battery Charger ATMega 8535 With LCD Display This is an idea that had just emerged from the author. In AVR-Based Battery Charger design ATMega 8535 With LCD Display is using AVR microcontroller processor charger with ATMega 8535, process the data viewer charger with LCD, a safety from a hot temperature with the temperature sensor LM35 and several buttons for setting the charger. And component power charger Battery Charger Based on AVR ATMega 8535 With LCD Display is a FET. Click to view larger Function-Based Battery Charger Part Series AVR ATMega 8535 With LCD Display ATMega 8535 AVR microcontroller serves as the controlling process of the charger. Button S1 - S5 as input data charger settings (setting the current, maximum temperature, peak voltage batterie...