Adafruit bq25185 USB / DC / Solar Charger with 3.3V Buck Board
100 units will be available shortly.
Adafruit bq25185 USB/DC/Solar Charger with 3.3V Buck Board
We're always looking for better ways to make projects portable, ensuring you can power and charge your battery no matter the available source. To take it a step further, we integrated a power supply chip, allowing you to run your project without needing a separate voltage regulator. The result? The Adafruit bq25185 USB/DC/Solar Charger with 3.3V Buck Board—a versatile all-in-one power solution!
At its core, this board features the bq25185 charger chip, which supports USB, DC, or solar charging, power path management, and high charge currents. It’s an excellent upgrade from MCP73833 or MCP73831-based chargers. We also added the TPS62569 buck converter, providing a stable 3.3V at up to 1A with high efficiency, maximizing power output from your battery.
Designed for 3.3V Electronics
Simply connect a 500mAh or larger battery to the JST PH 2-pin port, then charge it via USB or DC/solar input. The board provides two power outputs:
- 4.5V Max Load Output (from the bq25185 power path) – Ranges from 3.0V (low battery) to 4.5V (USB/DC/Solar active) at 1A max.
- 3.3V Regulated Output (via buck converter) – Delivers a stable 3.3V up to 1A, though it may dip to 3.0V when the battery is nearly empty.
Key Features
USB Type-C Connector – Includes 5.1k CC resistors, ensuring compatibility with any computer or power adapter for 5V input up to 1A. Data lines are also broken out on the bottom.
Dedicated DC/Solar Input – Two side pads allow 5–18V input as an alternative to USB. When using solar, the charger optimizes current draw, preventing voltage dips and providing near-MPPT functionality without extra components.
Adjustable Charge Rate – Defaults to 1A but can be lowered to 500mA by modifying the onboard jumper.
Smart Power Path Management – If your circuit draws power while charging, the board prioritizes external power, sending excess current to the battery instead of constantly cycling it, extending battery life.
Regulated Outputs:
- 4.5V Max Load Output – Never exceeds 4.5V, regardless of input voltage. High current draw may cause thermal throttling due to the onboard LDO regulator.
- 3.3V Regulated Output – A dedicated buck converter ensures efficient 3.3V output for low-power electronics.
Status LEDs:
- Orange – Charging
- Red – Fault
- Green – 3.3V Output Active
Additional Features:
- Enable Pad – Allows disabling the 3.3V buck converter when not needed.
- Secondary Battery Monitoring Pads – Check battery voltage via breakout pads on the bottom.
- Mounting Holes – For easy installation in enclosures.
Getting Started
This board is plug-and-play—adjust the charge jumper if needed, then connect:
- Battery → BATT port
- Load Circuit → Use 4.5V Max or 3.3V Regulated output
Both outputs will never exceed 4.5V or 3.3V, but they can drop as low as 3.0V if the battery is nearly empty.
Using with Solar Panels
For solar-powered projects, use a 5–7V solar panel (higher voltage panels will only generate excess heat). Connect it either by cutting the connector and wiring directly or using a 2.1mm adapter cable + terminal block for easy connection to the DC input.
Need More Power?
For a higher charge current or built-in DC jack, check out the bq24074 charger board—it supports up to 1.5A charging and includes an onboard 2.1mm DC plug. It doesn’t include a buck converter, but you can wire up the TPS62569 separately.
The Adafruit bq25185 USB / DC / Solar Charger with 3.3V Buck Board appears in the following collections:
SKU AF-6092
by Little Bird
