Charger
Using TP4056 Charger with Arduino Uno
What is the TP4056?
TP4056 practical reference
The standard single-cell lithium charging module, often bundled with over-charge/discharge protection circuitry on the same board. Built around the TP4056 linear charger IC (commonly paired with a DW01 protection chip and dual MOSFETs), it takes a 5V USB input and safely charges a single-cell Li-ion/LiPo battery with the correct constant-current/constant-voltage profile, while the protection circuitry cuts off the battery if it's charged too high, discharged too low, or short-circuited — making it the near-universal choice for any DIY project that charges its own lithium battery from USB.
Key specifications
- Chipset: TP4056 linear Li-ion/LiPo charger IC, commonly paired with a DW01A protection IC and dual MOSFETs on the same board
- Input voltage: 4.5V–5.5V DC, typically via Micro-USB or USB-C connector
- Charge voltage: 4.2V constant-voltage regulation for standard single-cell Li-ion/LiPo
- Charge current: Adjustable via an onboard resistor (commonly set to ~1A by default, some boards include a resistor pad to change it)
- Charge algorithm: Constant-current / constant-voltage (CC/CV) with automatic trickle charge for deeply discharged cells and charge termination near full
- Protection features (on modules with DW01): Over-charge protection, over-discharge protection, over-current/short-circuit protection
- Status indication: Onboard LEDs typically indicate charging (red) and fully charged (blue/green), color scheme varies by board
- Interface: Passive power circuit — USB in, battery and load out, no digital interface required
Pinout and connection notes
Always verify whether your specific TP4056 board includes the DW01 protection chip (look for two extra small MOSFETs and a small SOT23-6 IC near the battery terminals) — bare TP4056-only boards without protection should never be used to directly power a load while charging, since an over-discharged or over-charged unprotected cell is a real fire risk. Boards with protection expose separate B+/B- (battery) and OUT+/OUT- (load) pads so the load can draw power safely even during charging.
- IN+ (USB VBUS): 5V input from USB, via Micro-USB or USB-C connector
- IN- (GND): USB ground
- B+ (Battery+): Connect to the positive terminal of the single-cell Li-ion/LiPo battery
- B- (Battery-): Connect to the negative terminal of the battery
- OUT+: Positive output to the project load, present on boards with a protection circuit and separate load output
- OUT-: Negative output to the project load
Integration checklist
- Confirm the exact part number and breakout-board revision.
- Verify supply voltage, current demand, logic levels, and signal direction against the datasheet.
- Check controller pin assignments and bus address or interface mode against the example code.
- Power up with external loads disconnected, then test signals before full integration.
- If readings or communication fail, check power and ground first, then pin mapping, interface settings, and library initialization.
Troubleshooting and reproducibility
Record the board used, wiring, library/version, supply arrangement, and measured behavior. Use the selected board-specific wiring example as the source of truth. Never assume visually similar modules share identical voltage tolerance or pin order.
Setting Up TP4056 with Arduino Uno
Wiring
| Component pin | Arduino Uno pin | Note |
|---|---|---|
| IN+ / IN- | USB / power adapter | Charging input — not connected to the Arduino |
| B+ / B- | — | To the single-cell Li-ion/LiPo battery |
| OUT+ | 5V pin | Bypasses the onboard regulator — fine since a Li-ion cell's 3.0-4.2V range stays close to 5V, but see notes on sag near empty |
| OUT- | GND |
Swipe sideways to see every column →
- TP4056 alone only handles charging — over-discharge and over-current protection depend on whether your specific board also carries the DW01A + dual-MOSFET protection circuit. Check for those extra ICs before trusting it to protect a cell from deep discharge.
- The onboard LED (usually red=charging, blue/green=full) shows charge state, not remaining charge. The snippet above gives a rough state-of-charge estimate instead — roughly 4.2V full, 3.0-3.3V nearly empty for a typical Li-ion cell.
- Size the divider so the battery's worst-case 4.2V never risks the board's ADC reference — a 10kΩ/10kΩ pair (halving the voltage) leaves comfortable headroom on a 5V-reference Uno.
Related Components
18650 Holder
Single-cell 18650 holder for portable project power.
AMS1117 33
Fixed 3.3V linear regulator for powering logic-level components.
LM2596
Adjustable buck converter for efficiently stepping down higher voltages to project logic levels.
MT3608
Adjustable step-up converter for boosting low battery voltages to component requirements.
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