Battery charger circuit using SCR.
Description.
A simple battery charger based on SCR is shown here.Here the SCR rectifies the AC mains voltage to charge the battery.When the battery connected to the charger gets discharged the battery voltage gets dropped.This inhibits the forward biasing voltage from reaching the base of the transistor Q1 through R4 and D2.This switches off the transistor.When the transistor is turned OFF,the gate of SCR (H1) gets the triggering voltage via R1 & D3.This makes the SCR to conduct and it starts to rectify the AC input voltage.The rectified voltage is given to the battery through the resistor R6(5W).This starts charging of the battery.
When the battery is completely charged the base of Q1 gets the forward bias signal through the voltage divider circuit made of R3,R4,R5 and D2.This turns the transistor ON.When the Q1 is turned ON the trigger voltage at the gate of SCR is cut off and the SCR is turned OFF.In this condition a very small amount of charge reaches the battery via R2 and D4 for trickle charging.Since the charging voltage is only half wave rectified ,this type of charger is suitable only for slow charging.For fast charging full wave rectified charging voltage is needed.
Circuit diagram with Parts list.
Notes.
- Assemble the circuit on a good quality PCB or common board.
- The transformer T1 can be 230V primary, 18V /3A secondary step down transformer.
- The voltage of the battery at which the charging should stop can be set by the POT R4.
- The battery can be connected to the charger circuit by using crocodile clips.
so good web site
How do I modify to Automatic 24V Battery Charger. what component should i change ? thanks
thanks
good website for all peson which want to get knowledge about circuit.
how can i modify to 24v battery charger.what changes are required to modify the circuit.
This document is really helpful, thanx a lot
i am working here in kuwait.
I have problem buying electronic parts here, since i came 5 years ago, this country has no enough electronic parts on stock.
Can you send me the equivalent numbers for the following:
1. SCR, 2N3668
2. DIODE, SD 50 ( can i use in4001 instead?)
TRANSISTOR, BC 148.
Thanks, and this site is very helpful to me, and helped a lot on my job as maintenance supervisor for food machineries….
Best regards,,
Edgardo
This site is much useful,Thanks
regards,
Gani
Can you send me the equivalent numbers for the following:
1. SCR, 2N3668
2. DIODE, SD 50 ( can i use in4001 instead?)
TRANSISTOR, BC 148.
2N3668~ TYN612
SD50~ 1N1615, 1N1348A, 1N3987, MR756 etc
BC148~ BC548,BC107,2N2222 etc
To protect the charger electronics from accidental reversing of battery polarity kindly add 1N5404 diode between R6 and F1 anode to R6.
very very good site
To protect the charger electronics from accidental reversing of battery polarity kindly add 1N5404 diode between R6 and F1 anode to R6.
Seetharaman
Polarity reversal protection is a good idea although not essential. Place the diode between the number 15 on the transformer and before any other components.