Auto Cut-Off 3.7 Volt Lithium-Ion Battery Charger Circuit. 5v battery charging circuit

TP4056 Lithium-Ion Cell Charging Module

TP4056 is a complete constant current-voltage linear charging module for single-cell 3.7 V lithium batteries. It will continuously monitor the voltage level of the battery during charging and discharging. The module operates with 5V 1A DC voltage, can be provided by the USB mini cable, commonly used in Smartphone chargers. Due to the low number of the external component count, make the TP4056 module ideally suited for your portable electronics applications.

TP4056 Module Specifications

Type Charger, Protection Board
Module TP4056
Battery Type Li-Ion, Li-Pol
Battery Voltage 3.7V to 4.2V
Input Current Max. 1050 mA (~1A)
Input Voltage 4-8V
Output Voltage 4.2V
Connector Type USB Mini
Charging Method Linear Charging 1%
Charging Precision 1.5%
Package SOP-8

TP4056 Module Features

  • Include Current Monitor
  • Under Voltage Lockout
  • Automatic Recharge
  • Charger and Protection Circuit in One Module
  • Two Status Pin to Indicate Charge Termination
  • Indicate the Presence of an Input Voltage
  • Preset 4.2V Charge Voltage with 1.5% Accuracy

Working Principle of TP4056 Module

Lithium-Ion and Lithium-Polymer cells may explode if a shorted, overcharged, charged, or discharged with too high currents. TP4056 module is a combination of charger and protection for single cell 3.7V lithium batteries. Hence this module will monitor the voltage level of the lithium battery during charging and discharging.

Inside the module IC TP4056A, DW01A, and P-type MOSFET FS8205A are used. The charging process is controlled by the TP4056A Liner voltage IC, charge current is set by connecting a 1.2KΩ resistor from RPROG (Pin: 2) to GND. The DW01A battery protection IC is designed to protect lithium-ion/polymer battery from damage or degrading the lifetime due to overcharge, overdischarge. No blocking diode is required due to the FS8205A internal PMOSFET architecture and has prevented to negative charge current circuit.

The recommended operating voltage for the TIP4056 module circuit is 4-8V, 1A DC supply. You can use any type of mobile charger and its cable to power this module. When the charger is turned ON, the RED led will go high indicating that the battery is being charged. Once the module charges the battery completely, it will automatically stop charging and the Red LED will turn OFF and the Blue LED will turn ON to indicate the completion.

Applications of TP4056 module

  • Cellular Telephones, PDAs, GPS
  • Charge and Discharge Lithium cells
  • Digital Still Cameras, Portable Devices
  • USB Bus-Powered Chargers, Chargers
  • Used with 5V booster for powering Arduino projects

Frequently Asked Question (FAQs)

You can connect only one lithium-ion battery to the TP4056 charger at a time. Connecting multiple batteries in parallel to the charger can be dangerous and may cause the batteries to overheat, which can result in fire or explosion.

The maximum charging capacity of the TP4056 is 1000 mA (1A). This means that the maximum charging current that can be supplied by the TP4056 is 1000 mA. However, the charging current can be set to lower values, such as 500 mA or 100 mA, by changing the value of the charging resistor on the board.

Technically, it is possible to charge a mobile phone battery with a TP4056 lithium-ion battery charger, but it may not be the best solution.

Mobile phone batteries are typically designed with more complex charging circuitry that includes various safety features such as overvoltage protection, overcurrent protection, and temperature sensing.

Charging a mobile phone battery with a simple TP4056 charger may not provide the necessary safety features and could potentially damage the battery or the phone.

No, the TP4056 lithium-ion battery charger does not have a built-in Battery Management System (BMS). This is a simple charging module that is designed to charge a single lithium-ion battery cell at a time.

The TP4056 charger may generate some amount of heat during charging, which is usually normal. However, excessive heat generation could be an indication of a problem.

If the charger module gets too hot to touch or starts emitting a burning smell, it’s important to immediately disconnect it from the power source and investigate the cause of the problem.

Some possible reasons why a charger may generate excessive heat are overloading, short circuit, damaged charger or battery, and high ambient temperature.

If the issue persists, it’s recommended to seek professional help or replace the charger to avoid any potential damage to the device or the battery being charged.

Posted by: Subhajit Barman

Hi there! One of my greatest passions is electrotechnics. Ever since 2007, I’ve been captivated by the intricate world of electronics. This fascination led me to establish Electrothinks in 2019, a platform dedicated to sharing my knowledge and discoveries in this field.

v battery charging circuit

In today’s project, we will build an Auto Cut-Off Lithium-Ion Battery Charger circuit. As you guys know in one of my previous projects, I made a circuit that can charge a lead acid battery, when the indicator LED turns green it indicates the battery is fully charged and the red LED indicates the battery is in charging condition. Now if you are charging a lithium-ion battery and the circuit has no auto-cut option then it can become very dangerous. Because the circuit only indicates that your battery is fully charged. Now, we have to remove the battery ourselves after full charge because that circuit doesn’t have an auto-cut option. And It will continue to charge the battery even after the green LED is lit up, this can become dangerous. Also If you forget to turn that off after some time the battery can explode. So that’s why I am building an upgraded version of the previous circuit and it comes with an auto-cut option. In today’s project, the battery charger circuit provides the automatic cut-off system when the battery is fully charged.

Circuit Diagram

PCB Design

After designing the schematic diagram of the Digital RPM Meter, the assembled components and wiring are too clumsy and looked very unprofessional. In fact, the wiring also has a chance of loose connection. To give it a clean and professional look and also to compress the size, I decided to build its PCB prototype using EasyEDA software as it is so simple to use. Now come to the main part, where we need to order our PCB prototype. I always prefer PCBWay for their quality assurance, fastest delivery and also for 24/7 customer support.

Why I Choose PCBWay as My First Preference?

I’ve done several runs with PCBWay and am happy with the results, it’s good quality. It is one of the most experienced PCB manufacturing companies based in China with an experience of more than a decade in the field of PCB prototype and fabrication. PCBWay has always been committed to technological innovation and meeting the needs of their customers from different industries in terms of quality, delivery, cost-effectiveness and any other demanding requests. The etching, solder mask, and hole sizes are all done well and that is what matters to me. It takes a few hours for a design to get approved and then a couple of days to finish and ship.

With more than a decade in the field of PCB prototypes and fabrication, PCBWay has proved its assurance from time to time. They always look at the customer’s needs from different regions in terms of quality, on-time delivery, cost-effectiveness and any other demanding requests.

These PCBs were manufactured by PCBWay and the finish quality really impressive, especially with the gold finish path. If you want to finish your product faster you could also ask PCBWay to make a panelized order where you receive multiple PCBs in a single panel. With this, you will also receive SMT Stencil from PCBWay, saving you time and effort. All the orders are high quality and could select a lot of settings such as thickness, flexible PCB, the colour of the solder masks, the number of layers, material, surface finish and more.

How to Adjust the Cut-Off Point by Varying the Preset?

First, we disconnect any battery supply or any type of input supply and then rotate the preset knob to the ground level. Then we take a variable DC power supply which has its output precisely adjusted to 4.2V which is the optimum full charging level of the standard 3.7V Lithium-Ion battery.

Connect this power supply to the output side of the circuit, across the points where the battery is supposed to be connected.

You will see the green LED illuminating. At this stage, the relay must switch ON, however, it won’t since there’s no 5V supply from the input side of the circuit. No worries, we can still set up the circuit by looking at the LEDs.

After this, slowly adjust the preset until the green LED just switches off and the red LED just switches ON.

That’s all, the auto cut-off set-up is complete for the circuit.

Working Principle of Auto Cut-Off 3.7 Volt Lithium-Ion Battery Charger

In the above-mentioned circuit, the charging process is driven by a BC547 NPN transistor and a relay. While charging the circuit, it takes input from a 5-volt adopter as shown above. After the battery charge reaches a certain point the transistor BC547 activates and it’s driving a relay that turns on and changes the COM pin’s attachment from NC to NO, which is connected to the green LED as it lits up after the relay change over indicates that the battery is fully charged.

That’s how the automatic cut-off lithium-ion battery charger circuit works depending on the NPN transistor and 5-volt relay.

Simple 18650 battery charger circuit- Charge controller with Auto cut-off

An 18650 battery charger circuit is specifically used to safely charge 3.7 volt lithium ion batteries. 18650 batteries are lithium-ion cells that are commonly used in several electronic devices such as laptops, bluetooth speakers, portable consumer electronics and power banks. They are called 18650 batteries because they are cylindrical, 18mm in diameter and 65mm in length.

In this piece, we will discuss common 18650 battery charger circuits and popular charge controller modules. Also, it will be helpful for DIY lithium battery charger circuits.

There are different ways to design an 18650 battery charger circuit, all of them have common basic building blocks. This circuit consists of a charging controller, a power supply, and a charging port:

The main block from above is the charge controller. The charging controller regulates the charging process to ensure that the battery is charged safely and efficiently. The charge controller sets and monitors the battery’s voltage and charge current to determine according to specific needs of a particular lithium battery. It also prevents the battery from being overcharged and deep discharge. This helps increase the life of a lithium battery and thus the device.

The power supply could be any AC adapter, a USB port, or a solar panel. The power supply provides stable DC voltage that directly can’t be used to charge li-ion batteries, thus a charge controller is used. The charging port is usually a female DC jack or a micro USB port. The charging port is an input to the charging controller, which monitors the battery and controls the charging process.

8650 battery charger circuit using TP4056 charge controller IC:

The TP4056 is a popular and most widely used battery charging controller IC. It is a simple and cost-effective IC that is designed for low-power portable electronic devices such as power banks. One of the main advantages of the TP4056 IC is its low cost and simplicity. It has a simple circuit and does not require any additional components to function. It is also widely available and can be easily purchased from online retailers or electronics suppliers.

The TP4056 IC has a built-in charge controller and voltage regulator that is capable of charging lithium-ion or lithium-polymer batteries. It supports USB and AC/DC power sources, and has several safety features to protect the battery and the charger from being damaged.

You could implement an 18650 battery charger circuit using TP4056 in two ways, one directly with the TP4056 module available in the market and other with the TP4056 charger IC. Both are discussed and explained in detail below:

auto, cut-off, volt, lithium-ion, battery, charger

Tp4056 circuit diagram

Below is the simple circuit diagram for the 18650 battery charger schematic according to the datasheet of Tp4056 with temperature sense disabled.

auto, cut-off, volt, lithium-ion, battery, charger

Only Red LED glows when the battery is charging and only Green LED glows when the battery is fully charged. These indicators are connected to pin number 7 and pin number 6 respectively.

So here’s the diagram: How to wire a TP4056?

IC TP4056, 2x LED indicator, 2x Cap= 10uF, Rprog= 1.2KΩ, 2x Resistor= 1KΩ, Rs= 0.4Ω, 3.7V Lithium cell, micro USB/ USB c female connector, pcb.

This circuit can be used only for charging purposes. Rprog is chosen to be 1.2KΩ for 1000mA of output current, this can be changed by setting different values of Rprog. If you have two 18650 lithium batteries, then by connecting them in parallel, each battery will charge at 500mA of current. If you connect three then it will charge them at 1000/3 mA each, thus it will take longer to fully charge each battery.

The charging current (IBAT) of the Li-ion cell can be set manually by choosing the value of Rprog. In all modes during charging, the voltage on pin 2 can be used to measure the charge current as follows:

The Rprog(KΩ) vs Ibat(mA) can be determined using following table :

Tp4056 module: 18650 Li-ion 3.7 v battery charger circuit

For more technical information, here is the TP4056 datasheet at the end of page or Datasheet of TP4056

Overall, the TP4056 is a good option for charging single-cell lithium-ion or lithium-polymer batteries in low-power applications. It is simple, cost-effective, and widely available, which makes it a popular choice among designers and manufacturers.

How many batteries can charge in TP4056?

You can charge one or more lithium battery cells with TP4056, but note that it has max 1000mA of charging current. So, when charging multiple cells you have to connect them in parallel. Also the charging current will be divided among them, which will make charging slower. It is recommended to utilize one or two cells at a time with this module.

What is the maximum output current of TP4056?

The maximum output current of TP4056 is 1000mA. It can be programmed to provide charging current from 130mA to 1000mA by changing the value of Rprog.

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SparkFun LiPo Charger/Booster. 5V/1A






auto, cut-off, volt, lithium-ion, battery, charger

Creative Commons images are CC BY 2.0

SparkFun LiPo Charger/Booster. 5V/1A

The SparkFun 5V/1A LiPo Charger/Booster is a no-nonsense circuit for generating one amp from a Lithium Polymer battery at 5V. This LiPo charger is a very economical choice that is equipped with a simple booster circuit utilizing the PAM2401 IC, and includes protection diodes so you can run multiple cells in series for an extra kick. While the booster circuit is in operation, this board can draw more current the lower the input voltage, making it perfect to deliver a strong charge in a small amount of time.

The circuit is constructed by feeding an MCP73831 charge controller IC to the LiPo port, and to the input of a PAM2401 boost controller. Multiple connection types are provided for the battery, charge source and switch to allow flexibility of application, and two LEDs provide feedback on system status. If you need more than 5V out of your project, the SparkFun LiPo Charger/Boosters can also be daisy-chained together to get a bigger bang for your buck.

Note: This is not a direct replacement for the SparkFun Power Cell, as it uses a different IC. Also, this board does not possess any undervoltage or other battery protection features, so we do recommend that you use it only with batteries with a built-in protection circuit.

  • Charger, microUSB, 500mA
  • Booster, 5V, 1A output
  • Form factor for our 1,000mAh batteries
  • Battery isolation switch with optional external connections
  • Enable pin broken out
  • Disabled current less than 10uA
  • LED indicators for power and charge
  • Super-clean output signal (high-frequency switching)

September 28, 2017

February 23, 2023

Monitor your LiPo battery with the LiPo fuel gauge! In this tutorial, we will be using the MAX17043 and MAX17048 to monitor a single cell, LiPo battery over the Arduino Serial Monitor. We will also connect a display to view the output without the need to connect the microcontroller to a computer.

Core Skill: Soldering

This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.

Skill Level: Noob. Some basic soldering is required, but it is limited to a just a few pins, basic through-hole soldering, and couple (if any) polarized components. A basic soldering iron is all you should need. See all skill levels

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

Skill Level: Competent. You will be required to reference a datasheet or schematic to know how to use a component. Your knowledge of a datasheet will only require basic features like power requirements, pinouts, or communications type. Also, you may need a power supply that?s greater than 12V or more than 1A worth of current. See all skill levels

Комментарии и мнения владельцев

Looking for answers to technical questions?

We welcome your Комментарии и мнения владельцев and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

I have tested 3 different PCBs with 3 different 10Ahr batteries, all providing a nominal 3.7-3.9V. I have been charging them with 1.2-2A USB wall chargers for most of the day. The charging LED has yet to turn off, but maybe they haven’t reached full charge, yet. As soon as I disconnect the micro-USB charger all LEDs turn off and I loose the 5V line. When the battery switch is in the ON position (no charger), the battery terminals sag to 0.5V and no 5V line from the booster (giving 10mV). With the battery switch in the OFF position, I read the nominal 3.8V on the Li-ion battery pack, and expectedly nothing else is powered. I have tried charging for 6 hours in both the ON and OFF battery switch positions, and still am not getting 5V out once the charger is disconnected. Is there something I am missing? I can power a circuit directly off of the batteries, so I know there is juice. I need the charging and management circuit though, as well as the 5V switcher line.

Hello!! I was using this circuit and everything was working fine. I tested this board by removing the battery and just by connecting through USB cable. A this moment, it is able to make 5v (which was expected), but, when I’m connecting this 5v to any load, the led stop glowing and there is no output at 5v output terminal. So, this board is working only when the battery is connected and we are using a USB cable to charge that but why its not working when we are powering it through USB cable( without the battery connection) and connecting it to the load?? When there is no battery, still we are getting voltage from USB which boost IC is converting to 5v. So, whats the difference when we are powering it through USB or LIPO battery?

Hi there, it sounds like you are looking for technical assistance. Please use the link in the banner above or the steps in the troubleshooting section, to get started with posting a topic in our forums.Our technical support team will do their best to assist you. That being said, my guess is that the charge that you are pulling is getting supplemented by the battery. Therefore, when you disconnect the battery the USB connection alone (through the charge circuit) can’t provide the current draw you need.

Hello! I would like to add a load sharing circuit to this board in order to use a LiPo battery as a backup battery. I’ve found this load sharing circuit. Do you see any problems in adding the load sharing circuit (Q1, D1 and R2 in my diagram) before the VIN pin of PAM2401? So that when USB power is applied the VIN pin of PAM2401 will be VUSB. VD1 (drop over D1) and when USB power is off the VIN pin of PAM2401 will be VBAT. VSD (drop over Q1). In both cases, my output (PAM2401 output) would be regulated to 5V. Is that correct? Thanks!

I have a question about this board. While charging a lipo does the board automatically disconnect the arduino from the lipo and power it off of the external power? I’ve heard that you shouldn’t charge a lipo while it is powering a device.

Chris is correct. Pulling the enable pin low disconnects the load from the battery.- I can’t remember now but it draws something in the order of microamps during disable. Alternately, I’ve found that minimal loads (10mA) will still allow the battery cycle to complete. So if you can put your device to sleep or disable all of its peripherals, that’s probably good enough.

I just read through the getting started guide and from that my understanding is no. There are two options for turning power to the battery off: the battery switch and the en pin. Hoping to bump this up as it would be great for the designer to answer the question. I’d like to use this in a simple circuit that can be plugged in to charge. What I’m trying to figure out, as you are, is do we need to instruct the end user to power off the device before charging, or can they simply plug it in? Even more specifically: i have a 1Ah LiPo, this, an Esp8266, and a small haptic motor. I’d like to package it up and let people re-charge it. Is that safe? Or, should I turn breakout the battery switch, and have people turn it off before plugging in to charge?

This is a pretty basic circuit, I’ve found that projects I make have a variety of needs so I have to get a bit creative depending on how I want the circuit to operate. If you want the load to automatically be disconnected, use a small N type mosfet to pull the enable pin low with the gate connected to the USB in rail through a resistor. If you require the load to stay active (and can tolerate a 0.5v drop) do the above but also put a pair of schottky diodes ORing the USB rail and the output rail to your load. That way the system will redirect power through the supply while pulling the booster offline. If there’s too much of a gap in power, build an RC filter on the gate to delay the disconnection. One project I built has a button wired to turn on the system (microcontroller) when held, and the microcontroller can then power itself off. So in this instance I simply shut the device down before charging. See this Enginursday. Thanks for the bump

So what is going to happen if I am providing power to the charger over USB while simultaneously drawing 1A from the PAM?

I recently bought this charger and a 1000mAh battery. I charged it with no issues, then used in my setup it until it stopped sending power. I plugged in a micro USB cable to charge it for 48hrs, and the charge light remained on the whole time. When I plugged it back into my setup, it died within 10 minutes. Do you know what might be going wrong? I noticed that there’s some damage to one of the circuit components: Could this be causing an issue?

I realized that I got the Ext SW switch and the Enable pin mixed up. I was trying to charge with the battery disconnected! Seems to be working now.

Sounds great! Sorry if it was confusing. As for that inductor, it shouldn’t be chipped like that but it probably won’t effect operation.- if the whole top comes off then maybe. It’s part of the boost circuit anyway. If it fails you’ll have poor (or no) current output capacity but the charger will still work. Good luck with your project!

Greetings, I was checking out the PAM2401 spec sheet, and the chip puts out a maximum of 3.0A at 5.0V, if I am not mistaken. The current limit is set by the external resistor, on pin #6 of the chip. If the pin is left floating (which apparently it is on your board, but maybe I cannot see the trace), then the current limit is 3.0A. So I’m wondering why don’t you call this a 5-V/3-A charger booster? At any rate, I could use the 3.0A, so if you would kindly point out this resistor R3 so I may remove it, I would be much obliged!

Good question. While the PAM has current limiting capacity through that resistor, the current limiting factor here is actually the inductor (as well as the source’s current capacity). Let’s say the thing is 100% efficient, 5W out = 5W in. If the output is delivering 1A at 5V, that’s 5W power output. If the input is at 2.5V, and 5W is required going in, it needs 2A of input current. The winding of the inductor has resistance which can get in the way of the operation at high currents. See more including some graphs in the hookup guide connecting a load section. All boosters have this property the lower the input voltage, the higher the input current. I designed this such that it can deliver 1A over the entire input voltage range of a LiPo. I actually took my measurements up to 1.3A on the output, but I’d rather provide something with a healthy margin that to call it a 1.3A booster.

Thanks for the fast reply MT, on a holiday no less. The graphs are indeed revealing. I don’t know enough about switch-mode regulators to understand fully, but I can appreciate Power In = Power Out (at 100% efficiency). It’s nice to know that there is some (substantial) margin above 1A output current. In my application, I am driving LEDs, a motor, and a fairly high wattage camera, so I will have to be careful about coordinating these things. If I had the 3A output, I would not have to worry nearly as much. Thanks again.

I’m using this board to light up 12 LEDs, and even with the charger connected, when I load the circuit the LEDs light up for one second, then turn off. Unfortunately I don’t have a multimeter to measure the current, but is this a symptom of an overloaded circuit? What could be going wrong? After this happens, it won’t turn on for a while until I charge it, but is connected to a 1000mAh battery, which I don’t think is empty

Above it says includes protection diodes so you can run multiple cells in series for an extra kick. This is misleading and should say multiple charger/boost boards in series instead of cells. The PAM2401 datasheet shows a max input voltage of 4.75V, which is less than 2 lipo cells in series. And the MCP73831 doesn’t look like it will charge cells in series. Running cells in series would likely kill the board.

is this available for higher voltage like 6 or 7v? If not are there any solutions for 6v battery charging?

Meh. Still waiting for a 2-3S Lipo board with 2-5A output at 5V. As mentioned the Adafruit board has been out for a while now and 1A is old news. I have plenty of applications for a 2a board that something like this can’t be used for. Find me a budget all-in-one 20.25 board for 2-5A and I’m in.

Would I be able to shut down the charging circuit using a microcontroller when the temperature gets below freezing, without turning off the load? Or does the charging IC do that automatically? According to a brief reading into the datasheet it appears to not have this functionality, unless there’s something I’m missing.

That’s kind of an interesting problem, you want to continue to boost but not charge, all while leaving the charger connected. There’s no shutdown pin on the charger IC. I would investigate using a mosfet to switch the charger in and out of the circuit.

Looking for an easy way to adjust the output voltage, although it is not as straightforward as the LiPower. I tried changing R4 to 688k and 488k just to see if I could get the divider to alter the output, but the output voltage remained the same at 5.1. Is the inductor critical in reducing the boost? I can’t say the datasheet or application notes are very helpful. I am looking for something in the 3.6-4.2V range so I don’t have to use another stage of regulator.

The booster is regulating to 0.6V on the feedback pin (FB). Adjust the voltage divider made by R1 and R4 using 0.6 and your desired output voltage as constraints, and it should be OK. I solved R4=600k (with R1=100k) for 4.2V output. maybe there’s something else going on here. The inductor value is not critical to regulation voltage. Also, R4 is stuffed with 750K from the factory so I’m not sure what’s up. I’ll let you know if I discover anything. Keep in mind you can’t buck down from a larger battery voltage! The PAM2401 only boosts.

I replaced R4 with a 680k and I’m getting 3.6 volts. Shouldn’t I be getting higher than the 4.2 you calculated? Am I doing something wrong?

Thanks for the reply. For the record, I am boosting from a 3.0V lithium primary source. I was completely stumped this morning, so I downloaded the Eagle files. Just noticed that there is an identical 750k (R2) that I thought was R4. Whoops.- wrong resistor! Perhaps R2 isn’t too important.since that tiny 750k is long gone anyway. It might be helpful to spin future versions of this board with silkscreen, or at least the voltage divider labeled. I am loving the 1A boost capability of this chip, excited to see it in action.

Nice product. I can see lots of places I could use it. A couple of questions about the design. I noticed 2 22uF caps on the output. Is this because 22uF was deemed not sufficient? And by using 3 22uF caps you get a better volume discount than on 1 22uF and 1 47uF? Also, what is the purpose of the 2 schottky diodes on the output? I get why one (to chain chargers) but why 2?

Thanks! My main concern when designing this was to make sure the voltage was very noise-free on the output. I can’t stand supplies that whine! With that in mind, output capacitance required is a based on the transient load characteristics, which I don’t have any control over. a single 22uF may have been fine, but two is better here! And yes, I was considering that less specific components on the board means less work to build, even if it’s only a single reel in a machine. The diodes allow the boards to be used in series.- see the hookup guide for more info. If one goes dead in a chain, the current will be passed by.

Customer Reviews

Great little circuit

about 3 years ago by Member #1614611 verified purchaser

Works as advertised. One comment: Reading the description I expected the enable pin would disable the boost, but I found it disables all output. Re-reading the spec, that is what it says. Thus there apparently is no way to disable boost.

It delivers on it’s promises

about a month ago by Member #583789 verified purchaser

The small size is perfect for a small battery box I built as an alternative to the 4-AA battery power source for a portable sky tracker for astrophotography. The combination of charging and boosting as well as a battery disconnect switch capability without snipping battery leads is a dream come true for small hobby builds. And the red Power On LED is night-vision friendly.

auto, cut-off, volt, lithium-ion, battery, charger

Note that the math to calculate your battery capacity might not be simple for your load. This circuit will bend over backwards to meet the power needs of the load in spite of a falling input voltage, which means that the current draw from the battery will increase as time goes on. The worthy LiPo batteries include a low voltage cutoff function to avoid damage by being over drawn. My tracker draws a consistent 50 mA and I was able to get just 16 hours of operation from a 1400 mAH LiPo battery. The simplistic math is 1400/50 = 28 hours. So it would be best to test your project if you need to rely on it for a long running session, and maybe consider selecting a larger battery than the simple math would suggest.

I’m giving it 4 stars: starting with 5 for doing exactly what it says, then taking off 1 for the unavoidable realities of physics that aren’t Sparkfun’s fault.

Using the TP4056: There’s a right way, and a wrong way for safe charging of Lithium Ion batteries with this chip!

    An easy to use battery charger chip.

The TP4056 chip is a lithium Ion battery charger for a single cell battery, protecting the cell from over and under charging. It has two status outputs indicating charging in progress, and charging complete and a programmable charge current of up to 1A.

You can use it to charge batteries directly from a USB port since the working input voltage range is 4V ~ 8V. However, remember the maximum current from a USB port is 500mA.

Here you are looking at the 3 chip breakout board (TP4056. middle, DW01A. top right, and 8205A dual MOSFET. bottom right).

  • How to use the TP4056 breakout board.
  • How to use the TP4056 safely.
  • How the DW01A works on the TP4056 breakout board.
  • How to set temperature limits using the TP4056 TEMP input.

Note: You need to change the current programming resistor on the breakout board to match the lithium battery you are using. the default is 1.2k which is for a 1Ah (1000mAh) battery.

Lithium batteries can be dangerous if not charged properly and that’s why the TP4056 is useful as it stops over voltage and current charging by detecting specific voltage conditions.

There are a lot of circuits out there that show the use of the TP4056 as both a charger and a load driver. Not Good. If a load is attached to the battery while charging, then the TP4056 may not detect when the charge current has fallen to C/10. So it could continue charging. this could be dangerous.

You should never use the TP4056 as a charger and as a load driver at the same time. When charging the battery, switch off the load, and when loading the battery, switch off the charger. Alternatively use a PMOSFET, a resistor and a Schottky diode (See page 2 on how to do this).

Lithium batteries can not absorb overcharge. the current must be cut off after charging. If not there could be thermal runaway.

TP4056 module Datasheet

Download the TP4056 Datasheet here.

TP4056 Specifications

[trckl = Trickle charge, trhsy = Trickle Charge Hysteresis]

TP4056 Current Programming Resistor

The programming resistor (R3 or Rprog) is set to 1k2 which provides 1A programming charge rate or 1C. If your battery is not 1000mAh (1Ah), then you need to remove R3 and replace it with the correct one following the information in the table on the right.

TP4056 Status indicator LEDs

The table shows the state of LEDs for various charging states:

TP4056 Charger Module Schematic

This is the schematic of the popular breakout board with label 03962A this shows the TP4056 pinout for the breakout board.

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When charging a battery using the above board connect the battery to B and B- and disconnect OUT and OUT- from your circuit. When using the battery disconnect the 5V input and take the output voltage from OUT and OUT- to your circuit.

TP4056 Connections

The following diagram shows a typical setup (from the datasheet). The block diagram also shows the TP456 pinout for the 8 pin SMD device.

Here you can see the two status LEDs (CHRGn, STDBYn), Battery connection (BAT), Current control connection (PROG) and TEMP connection. Some LI batteries have an internal thermistor that you can connect as shown above. In the breakout boards available generally TEMP is not used and connected to Ground.

TP4056 reverse polarity protection

The TP4056 does not give you reverse polarity protection so if you wire up the battery the wrong way round then you’ll get smoke!

Actually, there is no TP4056 reverse polarity protection and the DW01A battery protection IC (on the breakout board) is being used in the wrong way (or not in the best way)! If used correctly the DW01A does provide reverse polarity protection for a battery.

DW01A Battery Protector Chip

On some breakout boards there are an extra 2 chips. One is the DW01A and the other is a dual N Channel MOSFET required by the DW01A chip.

This chip provides battery protection but it is not used in the right way on this board and so only provides short circuit protection (and over current protection). It should provide all of the following:

Charger input protection

  • Short Circuit detector.
  • Over current detector.
  • Charger Detector.
  • Reverse charger detection (overstress high current?).

Battery monitoring

  • Overcharge Detector (battery voltage too high).
  • Overdischarge Detector (battery voltage too low).

DW01A and TP4056 breakout Board

On the breakout board, the chip is soldered to the TP4056 so this can never be connected the wrong way round at the charger input. At the other side the DW01A does not protect from connecting the battery the wrong way round!

  • Stops discharging at voltages below 2.9V; Here trickle charge activates. The DW01A threshold is ~ 2.4V; So it will never activate.
  • Stops charging at voltages above 4.2V. The DW01A threshold is ~ 4.3V; So it will never activate.

The only function that will operate is the overcurrent protection and short circuit protection. These will activate at around 3A when using the 8205A dual Mosfet.


This article continues on page 2, where you can find out how to use the TP4056 in the correct way (most circuits are not correct).

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