Summary of 12V SLA LEAD ACID BATTERY CHARGER USING BQ24450
This article describes a 12V SLA lead-acid battery charger designed for batteries up to 12Ah capacity. The core component is the BQ24450 chip, which manages charging current and voltage to optimize battery life. It features temperature compensation without external components, supports NPN or PNP pass transistors, and includes internal comparators for status monitoring. The circuit can function as either a constant-voltage float charger or a dual-voltage boost-float controller.
Parts used in the 12V SLA Lead Acid Battery Charger:
- BQ24450 chip
- Current sense resistor
- External pass transistor (NPN or PNP)
- Precision voltage reference
- Voltage-regulating amplifier
- Current-regulating amplifier
- Status control pins
This project has been developed to charge SLA (Lead Acid Batteries) . It helps to charge 12V Lead-acid battery up to 12Ah in capacity. Specific current output is possible by altering the current sense resistor. The BQ24450 chip contains all the necessary circuitry to optimally control the charging of valve-regulated lead-acid batteries. The IC controls the charging current as well as the charging voltage to safely and efficiently charge the battery, maximizing battery capacity and life. Depending on the application, the IC can be configured as a simple constant-voltage float charge controller or a dual-voltage float-cum-boost charge controller.
The built-in precision voltage reference is especially temperature-compensated to track the characteristics of lead-acid cells and maintains optimum charging voltage over an extended temperature range without using any external components. The ICs low current consumption allows for accurate temperature monitoring by minimizing self-heating effects.
The IC can support a wide range of battery capacities and charging currents, limited only by the selection of the external pass transistor. The versatile driver for the external pass transistor supports both NPN and PNP types and provides at least 25mA of base drive current.
In addition to the voltage- and current-regulating amplifiers, the IC features comparators that monitor the charging voltage and current. These comparators feed into an internal state machine that sequences the charge cycle. Some of these comparator outputs are made available as status signals at external pins of the IC. These status and control pins can be connected to a processor, or they can be connected up in flexible ways for standalone applications.
Read more: 12V SLA LEAD ACID BATTERY CHARGER USING BQ24450
- What is the maximum capacity of the battery this project charges?
The project helps charge a 12V lead-acid battery up to 12Ah in capacity. - How can specific current output be achieved?
Specific current output is possible by altering the current sense resistor. - Does the IC require external components for temperature compensation?
No, the built-in precision voltage reference is temperature-compensated without using any external components. - Can the IC support both NPN and PNP transistors?
Yes, the versatile driver for the external pass transistor supports both NPN and PNP types. - What are the two configuration modes for the IC?
The IC can be configured as a simple constant-voltage float charge controller or a dual-voltage float-cum-boost charge controller. - How does the IC monitor the charging cycle?
Comparators monitor voltage and current, feeding into an internal state machine that sequences the charge cycle. - Can the status signals be connected to a processor?
Yes, some comparator outputs available as status signals at external pins can be connected to a processor.
