Friday, August 19, 2016

9.6V/1.5A Automatic Portable Battery Charger Circuit using LM317 IC

Electronic Kit School. - There are many kinds of voltage output of charger circuit that provide to you that work automatically or not when charge the battery until fully. Usually the kinds of rechargeable cell battery that can charge are NiMH and NiCD.

It is very nice when you can design circuit of charger that can work automatically. It mean that after the battery fully charge the circuit will automatically shut off and circuit like the open switch and charger not fill the power again to battery. 

In this article we will give you one electronic circuit design that give you 9.6V/1.5A Automatic Portable Battery Charger Circuit that can also will automatically shut off when it's fully charged with more than 9.6 volt. In this circuit also can charge the batteries 8 pcs that series to arrange. This circuit very suitable to charge the rechargeable cell battery A Low Dropout Voltage Power Bank Smartphone Charger Circuit Based on LM1086 IC.

The circuit of 9.6V/1.5A Automatic Portable Battery Charger Circuit based on LM317 IC that very popular for adjustable and regulated power supply design. The maximum output current that provide in this circuit is 1.5A.


Figure 1. 9.6V/1.5A Automatic Portable Battery Charger Circuit using LM317 IC

Component Parts

  1. Transformer 12-CT-12 with 3A
  2. Resistors
  3. Transistor Q1 C828
  4. Capacitors
  5. Diode
  6. LM317 IC
  7. Battery
  8. LEDs
  9. Zener Diode 9.1V
  10. Variable resistor

Circuit like in Figure 1 above show you about 9.6V/1.5A Automatic Portable Battery Charger Circuit using LM317 IC that can charger your 8 Pcs rechargeable cell battery . In this circuit has 2 LEDs (D1 and D2) indicator served as show the charging status and LED will be off when the battery is fully charged. Other function of this LED is indicate that the circuit is connected correctly to give perfect working.

The input voltage that can be given in this circuit ranging from 220V/50Hz with transfomer with output 12V-CT-12V and 3 Ampere. 
How this Circuit Work?

Diodes D1, D2 connected from transformer output voltage that served as  to convert low AC voltage to pulsating DC voltage. More pulsating DC voltage process do by the C1 capacitor to remove the AC ripples.

The output from C1 as DC voltage is unregulated DC voltage. The LM317 IC in here is variable voltage regulator to provide regulated DC voltage adjustable. By varying the pot 10k which is connected to the adjust pin of LM317, it will give the range 1.2V to 37V of regulated voltage output and with the maximum output current is 1.5A.  The output voltage of this voltage regulator is varied.

Diode D5 is used to avoid the discharge of battery when main supply fails. So, the Lm317 voltage regulator output is applied to the battery through the diode D5 and resistor R5. The zener diode D6 which connected in reverse bias conducts when battery charges fully. Transistor C828 as the NPN transistor gets the current through the zener D6 that make the total current is grounded and Green LED D3 will display.

To indicate the charge process RED LED D4 used to do this work. And the resistor R3 is used to protect the green LED from high voltages. 

  • Please use heat sink to reduce the heat from LM317L