SparkFun Thing Plus - ESP32-S3
The SparkFun Thing Plus ESP32-S3 is a feature-rich Feather-compatible board with 16MB flash, 8MB PSRAM, Qwiic I2C connector, MicroSD slot, LiPo charger with fuel gauge, and USB-C OTG. It packs the most peripheral integration of any ESP32-S3 board, designed for data logging and field-deployed projects.
Best for data logging and field deployments needing battery, SD card, and Qwiic, skip if size or cost is the primary concern.
Where to Buy
Pros
- 16MB flash — double the standard, room for large firmware, OTA, and file systems
- MAX17048 fuel gauge provides accurate battery percentage readings
- MicroSD card slot for local data logging without WiFi dependency
- Qwiic / STEMMA QT connector for plug-and-play I2C sensors
- Single-cell LiPo charger with power path management
Cons
- Higher price point than Espressif reference boards and XIAO alternatives
- 58.4x22.9mm is larger than the XIAO (21x17.5mm) or QT Py (22x17.8mm)
- 21 GPIO pins — fewer than the DevKitC's 45 due to Feather form factor
Peripheral Integration
The Thing Plus stands out for what SparkFun built around the ESP32-S3 chip. The MicroSD card slot provides local storage independent of WiFi connectivity. The MAX17048 fuel gauge IC gives accurate battery percentage readings over I2C — most boards only tell you voltage, which maps poorly to remaining capacity.
The Qwiic connector is compatible with SparkFun's 300+ Qwiic sensor breakouts and Adafruit's STEMMA QT ecosystem. This I2C plug-and-play system eliminates wiring errors and speeds up prototyping. Combined with the MicroSD, you can build a complete data logging system — sensor, storage, and battery management — with no soldering.
Storage and Memory
16MB of flash is double what Espressif's reference boards offer. This extra storage matters for three scenarios: large OTA update partitions (you can keep the current firmware while downloading the new one), extensive SPIFFS or LittleFS file systems for web server assets, and fat firmware images with many libraries.
The 8MB PSRAM matches the DevKitC and XIAO, providing ample buffer space for data processing, camera frames, or ML model weights. The combination of 16MB flash and 8MB PSRAM gives the Thing Plus the highest total memory of any board in this comparison.
Battery Management
The single-cell LiPo charger charges via USB-C when connected and automatically switches to battery when USB is disconnected. Power path management means the device runs from USB power while charging the battery, rather than cycling through the battery.
The MAX17048 fuel gauge is the real differentiator. It uses a ModelGauge algorithm to estimate remaining battery capacity from voltage curves, compensating for temperature and load. Your firmware can read battery percentage over I2C and make decisions — transmit a low-battery alert, reduce sample rate to extend life, or trigger a graceful shutdown.
Full Specifications
Processor
| Specification | Value |
|---|---|
| Architecture | Xtensa LX7 |
| CPU Cores | 2 |
| Clock Speed | 240 MHz |
Memory
| Specification | Value |
|---|---|
| Flash | 16 MB |
| SRAM | 512 KB |
| PSRAM | 8 MB |
Connectivity
| Specification | Value |
|---|---|
| WiFi | 802.11 b/g/n |
| Bluetooth | 5.0 |
I/O & Interfaces
| Specification | Value |
|---|---|
| GPIO Pins | 21 |
| ADC Channels | 14 |
| SPI | 2 |
| I2C | 1 |
| UART | 2 |
| USB | USB-C (OTG) |
| Qwiic | 1x Qwiic / STEMMA QT |
| SD Card | MicroSD slot |
Power
| Specification | Value |
|---|---|
| Input Voltage | 5 V |
| Deep Sleep Current | ~10 uA |
| Battery Charging | Single-cell LiPo charger |
| Fuel Gauge | MAX17048 fuel gauge |
Physical
| Specification | Value |
|---|---|
| Dimensions | 58.4 x 22.9 mm |
| Form Factor | Thing Plus (Feather-compatible) |
Who Should Buy This
MicroSD logs data locally when WiFi is unavailable. LiPo charger with fuel gauge manages solar-charged batteries. Qwiic connects weather sensors without soldering. 16MB flash holds weeks of buffered data.
Qwiic GPS module connects instantly. MicroSD stores track logs. Fuel gauge reports battery level to the application. Feather form factor fits standard enclosures.
SparkFun boards carry a premium for their integration and documentation. The XIAO ESP32S3 has the same chip with battery charging at a lower price, or the ESP32-S3-DevKitC for raw capability.
Better alternative: Seeed Studio XIAO ESP32S3
At 58.4x22.9mm, it is 3x larger than the XIAO. The Feather form factor is designed for enclosures, not wearables.
Better alternative: Seeed Studio XIAO ESP32S3
Frequently Asked Questions
What is the fuel gauge and why does it matter?
The MAX17048 fuel gauge IC estimates remaining battery percentage using voltage modeling. Unlike raw voltage readings which vary with load and temperature, the fuel gauge provides accurate state-of-charge. Your firmware can report actual battery percentage to users or adjust behavior based on remaining power.
Is the Thing Plus compatible with Feather accessories?
Yes. The Thing Plus uses the Feather-compatible form factor with matching pin layout. Feather Wings (add-on boards) from Adafruit, SparkFun, and third parties should be compatible, though always verify pin assignments for your specific Wing.
Thing Plus vs XIAO ESP32S3: which should I choose?
Choose the Thing Plus for data logging (SD card), battery monitoring (fuel gauge), and Qwiic ecosystem. Choose the XIAO for compact size (21mm vs 58mm). Both have 8MB PSRAM and battery charging, but the Thing Plus adds SD and fuel gauge.
Can I use the MicroSD card and WiFi simultaneously?
Yes. The SD card uses SPI, not the same interface as WiFi. You can log data to SD while maintaining a WiFi connection. The ESP32-S3's dual-core architecture handles both tasks on separate cores without conflict.
Does the Thing Plus support camera modules?
The ESP32-S3 chip supports cameras via DVP interface, but SparkFun does not break out the camera pins on the Thing Plus. For camera projects, use the ESP32-S3-DevKitC or XIAO ESP32S3 Sense.