Battery Splitter Circuit Diagram

Source: http://www.circuitsuggest.com/battery-splitter.html

• It can charge 6V, 9V and 12V batteries. Batteries rated at other voltages can be charged by changing the values of zener diodes ZD1 and ZD2.
• Constant current can be set as per the battery capacity by using a potmeter and multimeter in series with the battery.
• Once the battery is fully charged, it will attain certain voltage level (e.g. 13.5-14.2V in the case of a 12V battery), give indication and the charger will switch off automatically. You need not remove the battery from the circuit.
• If the battery is discharged below a limit, it will give deep-discharge indication.
• Quiescent current is less than 5 mA and mostly due to zeners.
• DC source voltage (VCC) ranges from 9V to 24V.
• The charger is short-circuit protected.

R2 and T1 limit the charging current if something fails or battery terminals get short-circuited accidentally. To set a charging current, while a multimeter is connected in series with the battery and source supply is present, adjust potmeter VR1 slowly until the charging current reaches its required value.

Adjust VR2 when the battery is fully charged (say, 13.5V in case of a 12V battery) so that VGS of T5 is set to zero and hence charging current stops flowing to the battery. LED1 glows to indicate that the battery is fully charged. When LED1 glows, the internal LED of the optocoupler also glows and the internal transistor conducts. As a result, gate-source voltage (VGS) of MOSFET T5 becomes zero and charging stops.

If the battery terminal voltage drops to, say, 11V in case of a 12V battery, adjust potmeter VR3 such that transistor T3 is cut-off and T4 conducts. LED2 will glow to indicate that the battery voltage is low.

Values of zener diodes ZD1 and ZD2 will be the same for 6V, 9V and 12V batteries. For other voltages, you need to suitably change the values of ZD1 and ZD2. Charging current provided by this circuit is 1 mA to 1 A, and no heat-sink is required for T5. If the maximum charging current required is 5A, put another LM236-5 in series with diode D2, change the value of R11 to 1 kilo-ohm, replace D1 with two SB560 devices in parallel and provide a good heat-sink for MOSFET T1. TO-220 package of IRF540 can handle up to 50W.

Assemble the circuit on a general-purpose PCB and enclose in a box after setting the charging current, overcharge voltage and deep-discharge voltage. Mount potmeters VR1, VR2 and VR3 on the front panel of the box.

Battery Charger Circuit Diagram

Source: http://www.electronicsforu.com

Usually , NiCd batteries must be charged in 14 hours at a charging current equal with a tenth percent from battery capacity. For example, a 500 mAh is charged at 50 mA for 14 hours. If the charging current is too high this will damage the battery.

The level of charging current is controlled with P1 between 0 mA – 1000 mA. T1 is opened when the NiCd battery is connected with the right polarity or if the output terminals are empty. T2 must be mounted on a heatsink.

If you cannot obtain a BD679, then replace it with any NPN medium power Darlington having the output parameters at 30V and 2A. By lowering R3 value the maximum output current can be increased up to 1A.

NiCd Battery Charger Circuit Diagram

NiCd Charger PCB Layout

5V battery type with 4 or 5 cells are charged at 55mA. Again, with P1 adjust the NiCd charger circuit so it disconnects after 14 hours. Window inferior level must be set at 0.8V below this value.

Automatic 9V Battery NiCd Charger diagram

D1 is a protection diode while R1 and C1 decouple the power live of the IC1 U2401B. D3 is for protecting the batteries in case we mount them wrong. R4 limits the current at 5 mA. After we connect the adapter to the main line, the button batteries will start to charge at maximum current for a period of time, after this it will start to charge in impulses. The impulse charging it is always made at 1/10 of the maximum charging current.

R5 = 0,1 * R4
button battery charging time table

Button battery charger circuit diagram

If you can handle a cutter, gently cut off the isolation and reveal the wires inside. See what colors the wires have that are connected at pin 1 and 4. Note or remember and then with an soldering gun solder the cables to the iPhone charger circuit like in the schematic.

iPhone charger circuit

If you don’t want to cut the iPhone cable, buy an USB extension cord.
Make sure the positive and negative terminals are connected correctly and use a voltmeter to make sure everything is correct.

usb pinout

We received informations that you can use it as an iPhone 3G charger but we cannot guarantee it.

Disclaimer: I will not be responsible if you destroy you iPhone with the charger information posted here.

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When the battery voltage level rises, the voltage at the non-inverting input will also rise and by certain level (set with P1) the non-inverting input has a higher level than the inverting input.
The comparator is designed to have a hysteresis that prevents the circuit from “oscillating” (constantly switching on or off the relay) that could be cause by slight changes ti the battery voltage. This hysteresis is set with P2 which also sets the minimum battery voltage level at which the charging resumes.

Automatic battery charger circuit calibration

The best way to calibrate the circuit is to use a variable voltage, regulated power supply. This is connected to the circuit in the place of the NiCad battery. Set the regulated power supply to 14.5 volts and adjust the P1 to a point where the relay snaps open. Newt, set the regulated power supply to 12.4 volts and adjust P2 to a point the relay closes back. You might need to repeat this procedure severals time since P1 and P2 have an effect on each other.

Automatic battery charger circuit diagram

Power transistor Q1 and Q2 are connected as series regulators to control the battery chargers’s ouput voltage and charge-current rate. An LM317 adjustable voltage regulator supplies the drive signal to the bases of power transistor Q1 and Q2. Potentiometer R9 sets the output-voltage level. A current-sampling resistor, R8 (a 0.1Ω 5W unit), is connected between the negative output lead and circuit ground. For each amp of charging current that flows through R8, a 100mV output is developed across it. The voltage developed across R8 is fed to one input of comparator U3. The other input of the comparator is connected to variable resistor R10.

As the charging voltage across the battery begins to drop, the current through R8 decreases. Then the voltage feeding pin 5 of U3 decreases, and the comparator output follows, turning Q3 back off, which completes the signal’s circular path to regulate the battery’s charging current.

The charging current can be set by adjusting R10 for the desired current. The circuit’s output voltage is set by R9.
This can be used as a military battery charger.

Universal battery charger circuit diagram

Battery charger circuit diagram

Diode D3 prevents the battery from discharging back into IC1 if the input supply is disconnected. Resistor R3 provides current to switch one transistor TR1 when the input supply is present.
Shunt regulator IC2, resistors R6, R7 and preset potentiometer VR1 form the network which determines whether on not the battery has reached its required voltage. When the voltage at IC2′s reference input reaches 2.5V, IC2 switches on its internal transistor, connecting IC1′s ADJ (adjust) pin to 0V. In this condition, IC2 holds IC1 in constant current supply mode. Capacitor C3 helps to stabilise the switching of IC2.
Capacitor C1 and C2 decouple the DC input supply voltage. Light emitting diode D1 is a power-on indicator, and LED D2 is turned on when constant voltage mode is activated. A heatsink may be needed with IC1.
In use, adjust preset VR1 so that the voltage at the output suits the peak voltage required by the sealed lead-acid battery,which is usually printed on its body. Once adjusted correctly, it should not need further adjustment.
The authos used a 12V 600mA DC adapter for powering the dual mode battery charger circuit. The battery with which it is used has a peak voltage range of 6.9V to 7.12V.

The charging current is automatically regulated to 4.2 amperes. Once the charging current reaches 4A, the voltage drop at R1 will be 600 mV. In this case the transistor T1 will conduct and supplies current to T2.

NiCd battery charger circuit schematic

Transistor T2 in turn, shorts the base of T3 to ground thereby reducing or totally cutting off the base bias current of T4. The voltage difference between the collector voltage of T4 and the actual charging voltage of the NiCd battery is dissipated by T4. The power dissipation of T4 is therefore the product of the voltage difference and the charging current. In charging 6 volt batteries, the power dissipation can reach up to 40 watts, therefore you must mount T4 with a cooler.
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Printed circuit layout for battery charger

Parts placement for NiCd battery charger