This is my evaluation design for the BQ25886 from Texas Instruments for charging 2 Li-ion cells in series from USB. https://www.ti.com/product/BQ25886

In testing it behaves well with PCs and laptop USB ports & USB chargers that can supply 2A or more. Anecdotally I found this IC less "fragile" than the TP5100 and more feature rich.

The board integrates a battery balance & protection module and dual 18650 holder (this half can snap off for remote locating)

Boards will be assembled and tested using ICs from TI online Store. Cells are not included

Please note I have parts ready to assemble for around 20 boards but may need to assemble your board before shipping. I will try my best to have boards shipped 3-7 days from order date. Message me for other destinations not listed for shipping!

Applications:

• Portable speaker up to 30w
• Raspberry pi "UPS"
• Portable power supply

Ideal for applications with 10-15w constant current or 30w intermittent peak current.

Electrical Features

It will be shipped configured for ~1.6A target charge current and cut off voltage 8.4v

• Standalone operation
• Programmable charge current - max 2A (via 0805 resistor)
• Programmable charge voltage 8.2-8.8v (via 0805 resistor)
• Switched output via internal mosfet (5A max)
• "Instant on" when power applied even if cells heavily discharged
• Charge/Fault indicator status LEDs
• USB input aware, can do basic USB detection
• Low quiescent current across battery terminals. Observed 10-15 microamp.

Safety features:

• Battery temperature monitoring (during charge) via thermistor
• Pre-charge/trickle for heavily discharged cells
• Battery Protection module provides cell voltage balancing, over/under voltage and over current protection (based on HY2120CB battery protection ICs)

Physical Features

• USB Type C input
• Dual PCB mounted holder for 18650 cells
• PCB can be snapped in two for remote battery locating
• 105 x 90 mm x 25mm
• 3.5mm mounting holes with safe PCB track clearances
• Standard 1/10"/2.54mm header holes for status LEDs and switched output

That's about it, any questions on implementation or measurements etc please send a message