Preface
In multi-string power banks and outdoor power supplies, the equalization function for multi-string lithium batteries is often mentioned and is also applicable to lead-acid batteries, which also need to be charged equalized so that each group of batteries in the series battery pack is fully charged. In the past, multiple strings of lead-acid batteries were overcharged to achieve the equalization of the battery pack.
However, overcharging will decompose the electrolyte in the lead-acid battery, reduce the battery capacity, and shorten the battery life. By using a battery equalizer to charge the lost batteries individually, it is possible to accurately charge the lost batteries in the battery pack without having to overcharge the entire battery pack.
The charging head network got a lead-acid battery pack charge protection equalization module launched by Lianghe Electronics, which supports the use of 12V lead-acid batteries, supports 48/60/72V battery packs, and has built-in Bluetooth function, which can view battery voltage, voltage difference and other parameters on the mobile phone. This equalization module converts the battery pack into a deficit battery for separate charging by using the battery pack as the input power source. The following brings the dismantling of this lead-acid battery charge protection equalization module, and let's take a look at the internal design.
Appearance of Lianghe electronic lead-acid battery pack charge protection equalization module
The module body and connecting cables are packaged and stored in ziplock bags.
The equalization module has a black aluminum alloy housing with wiring sockets on the side.
Mark the product name, model and specification on the module shell, and the corresponding command function.
On the back of the module, the wiring diagram of the module is marked.
List of module terminals and included cables.
The side of the module is equipped with a terminal connecting the lead-acid battery pack, a power indicator, an overcharge protection indicator and an equalization indicator.
Close-up of the battery positive connection terminal and the split wire connection terminal.
The battery terminal is marked with a wire number, which corresponds to the battery, which is easy to install.
The length of the measured cable is 90cm.
The length of the module is approximately 113.2 mm measured using vernier calipers.
The width of the module is about 88.5 mm.
The thickness of the module is about 37.7mm.
The measured weight of the module is about 243.8g.
Dismantling of the charge protection equalization module of the lead-acid battery pack of Lianghe Electronics
After looking at the appearance of this module, let's disassemble it and take a look at the internal design together.
First, unscrew the set screws on both sides, where the internal indicator lights on the cover plate on one side of the socket are connected by a wire.
The PCBA module is fixed by slotting inside the housing.
Disconnect the connecting cables from the cover.
There are connectors on the back of the cover.
Close-up of the three SMD LEDs inside the cover.
The inside of the cover plate corresponds to the corners of the PCBA module glued and reinforced.
The front view of the PCBA module shows the MOS tube for switching lead-acid batteries at the top, and the diode and switching optocoupler at the bottom. In the lower left corner is the disconnector switching power supply, which is used to step down the bus to charge a separate battery. On the right side of the transformer, there is a buzzer, a main control MCU and a Bluetooth module.
Above the Bluetooth module is the step-down power supply circuit, the right side is provided with a MOS tube to control the charging switch, and the right side is a filter capacitor, which is connected to the socket. A small plate is also soldered to the bottom along with the filter capacitor.
There are no soldering elements on the back of the PCBA module.
There is a heat sink above the switching power supply chip, which is fixed by soldering.
Solder and remove the heat sink above the switching power supply chip.
The switching power supply chip is from DK Dongke, model DK112L, the chip integrates a high-voltage starting circuit, integrates a 700V switch tube, supports 85-265V input voltage, supports 12W output power, and adopts DIP8 package.
Dongke DK112 data information.
Close-up of a switching transformer.
The feedback optocoupler is set at the bottom of the transformer.
The rectifier diode and filter capacitor are welded on one side of the PCBA module, and the output filter capacitor specification is 1000μF 35V.
THE OUTPUT CONSTANT VOLTAGE AND CONSTANT CURRENT CONTROL CHIP IS FROM DIODES, MODEL AP4313, THE CHIP HAS A BUILT-IN 1.2V VOLTAGE REFERENCE, CURRENT SENSING CIRCUIT AND TWO OP AMPS, AND IS IN A SOT26 PACKAGE.
The main control MCU is from STC Hongjing, and the model is blocked by the Bluetooth transparent transmission module.
The Bluetooth transparent transmission module is connected by pin header soldering.
The module is equipped with a Bluetooth chip and a chip crystal oscillator.
蓝牙芯片丝印E2PD2344。
Close-up of the buzzer used to alert the alarm.
MCU外置TL431电压基准特写。
The step-down converter that powers the MCU is a XL7015E1 DC-DC converter with 100V input voltage, with an integrated switch with a switching frequency of 150KHz, a maximum output current of 0.8A, and an integrated short-circuit protection and thermal shutdown protection in a TO252-5L package.
A 100μH alloy inductor is used for step-down.
A total of 12 MOS tubes are used for battery switching.
Close-up of another 6 MOS tubes.
One of the 6 MOS transistors is from field effect, model CMD25N20A, NMOS, withstand voltage 200V, conduction resistance 170mΩ, and is available in a TO252 package.
The other 6 MOS tubes are from APM, model AP30P10D, NMOS, withstand voltage 100V, conduction resistance 36mΩ, and TO-252-3L package.
The A217 optocoupler is used to drive the MOS tube switch.
One MOS transistor from onsemi, model FQD7P20, PMOS, withstand voltage -200V, conduction resistance 690mΩ, in a D-PAK package.
The three MOS transistors are from AOS, model AOD403, PMOS, withstand voltage -30V, conduction resistance of 5.1mΩ, and use DPAK package.
Close-up of four SS520 Schottky diodes with a specification of 5A 200V.
A small board is soldered on the PCBA module.
The other side of the board is welded with diodes, transistors and chip resistors.
One filter capacitor is 10μF 160V.
The other filter capacitor is 22μF 50V.
The two non-polarized electrolytic capacitors are 10μF 100V.
The specifications of the two electrolytic capacitors are 220μF 50V.
A list of all dismantling and a family photo.
Summary of the dismantling of the charging head network
Lianghe Electronics' lead-acid battery pack charging protection equalization module supports 48V/60V/72V lead-acid battery pack charging, the module adopts a black aluminum alloy shell, and is equipped with a 90CM long connecting cable, the connecting line has been made of terminals, which is convenient for connecting the battery for installation. The module has a built-in Bluetooth module, which supports the mobile phone to display battery voltage and other parameters, grasp the battery running status, and support function settings.
The charging head network learned through dismantling that this module has a built-in switching power supply, and by stepping down the input voltage, the MCU detects the power loss of the series battery, and the MOS tube connects the switching power supply output to the corresponding battery to charge the battery with power loss. Among them, the main control chip of the switching power supply is from Dongke, the model DK112, the MCU is from STC macrocrystal, and the MOS tube is driven by optocoupler to realize separate isolation for charging the battery with loss of power.