A Simple Battery Charging Indicator Circuit using IC LM393 that shows whether a battery is charging is really important for managing how batteries get charged.
This circuit helps stop overcharging which can be harmful and makes charging safer and more efficient.
The main part of this design is the LM393 comparator integrated circuit which lights up an LED to show the charging status.
The whole circuit is simple and inexpensive making it a great tool for keeping an eye on and taking care of 12V lead-acid batteries.
Circuit Working:
Parts List:
| Component | Value / Part Number | Quantity | Power Rating |
|---|---|---|---|
| Resistors | 1M | 1 | 1/4W |
| 2.2k | 1 | 1/4W | |
| 1Ω | 1 | 0.5W | |
| 10k | 1 | 1/4W | |
| 1k | 1 | 1/4W | |
| Semiconductors | LM393 Comparator IC | 1 | – |
| 1N5819 Schottky Diode | 1 | – | |
| LED 5mm 20mA | 1 | – | |
| Battery | 12V Lead-acid Battery | 1 | – |
This circuit works by sensing the charging current that flows through a special resistor called R3 which has a resistance of 1Ω and can handle up to 0.5W of power.
It does this by measuring the voltage drop across this resistor.
The IC LM393 comparator is really important here because it controls whether the LED1 lights up to show if the battery is charging.
The battery charger is responsible for providing the right amount of current to the battery.
When the charging current goes through the shunt resistor R3 it creates a small voltage drop.
There is also a Schottky diode D1, that helps set a reference voltage for the circuit.
The LM393 comparator is good at noticing any changes in voltage.
If the charging current is strong enough the LED1 will light up showing that the battery is charging.
But as the battery gets closer to being fully charged the charging current starts to drop.
This means the voltage drop across the shunt resistor R3 also gets smaller.
The comparator picks up on this change and turns off the LED which means the battery is fully charged.
Formulas with Calculations:
For designing a Simple Battery Charging Indicator Circuit using IC LM393 use the following formulas with calculations for better understanding:
Voltage Drop Across Shunt Resistor R3:
Vshunt = Icharging × R3
For example, if the charging current is 1A, then:
Vshunt = 1A ×1Ω = 1V
Reference Voltage Set by R1 & R2:
The reference voltage at the inverting input Pin 2 of LM393 is determined using the resistor divider:
Vref = Vsupply × R2 / (R1+R2)
Assuming,
V_supply = 12V, R1 = 1M, R2 = 2.2k:
Vref=12V
This ensures that the comparator switches at a very low shunt voltage.
Comparator Operation:
When, V_shunt > V_ref, the output is LOW turning the LED ON.
When, V_shunt < V_ref, the output is HIGH turning the LED OFF.
How to Build:
To build a Simple Battery Charging Indicator Circuit using IC LM393 follow the below steps for connections:
- Assemble all the components mentioned in the above circuit diagram.
- Connect pin 1 of IC1 LM393 to negative of LED1 and positive of LED1 to one end of resistor R5 and other end of R5 resistor to positive supply.
- Connect pin 2 of IC1 LM393 to -12V battery through resistor R4.
- Connect pin 3 of IC1 LM393 between resistor R1 and resistor R2.
- Connect the 4 of IC1 LM393 to -12V battery.
- Connect a resistor R3 in series with a negative supply line of -12V of battery
- Connect a diode D1 parallels to resistor R3.
- Connect pin 8 of IC1 LM393 to +12V of battery
Conclusion:
This Simple Battery Charging Indicator Circuit using IC LM393 is a cool way to keep track of how your battery is charging.
It uses a simple method that checks the voltage with a shunt.
The IC LM393 comparator helps it switch on and off reliably while the Schottky diode helps fix any voltage drops.
This setup works great for car batteries, solar chargers and backup power systems.