SUNMOD03PU – Solar Charge Controller Module
3 A Configurable Solar Charge Controller Module with UART Interface and Load Control with Flasher, Photocell and Load Shutdown Inputs
A Compact Solar Module
Drop it into Your Design. Run Your Product on Solar Power, Day and Night
Fine-tune it for Your Battery, Panel, and Load — All Through a Simple UART Interface
SUNMOD03PU is a compact solar charge controller module designed to simplify the integration of solar power into embedded products. It combines intelligent battery charging, comprehensive protection features, configurable operating parameters, and integrated power switching in a compact module designed for direct integration onto a host PCB. It supports multiple battery chemistries, including GEL, flooded lead-acid, and LiFePO₄ batteries, and provides a UART interface for configuration and diagnostics.
SUNMOD03PU protects itself and the connected system against overvoltage, overcurrent, electrical faults, and common wiring mistakes. Its protection architecture tolerates reverse-polarity connections as well as accidental interchange of the battery, solar panel, and load connections— for example, connecting the battery to the panel input or applying the battery or panel to the load output—without damaging the module.
Protected by Design — Even Against Wiring Mistakes
Built-in MCU • Integrated Power Switches • Up to 50 W Power Delivery
SUNMOD03PU
Outdoor IoT • Solar Lighting & Signaling • Remote Monitoring • Automation • Agriculture • Battery-Backed Embedded Systems
Designed for a Wide Range of Applications
Configure operating parameters, monitor diagnostics, and manage SUNMOD03PU directly from your browser.
Integrate SUNMOD03PU into your application using Behvolt’s SDK, examples, and developer resources including C and Python libraries.
Hardware Backed by a Complete Software Stack
Configure • Customize • Deploy
SUNMOD Configuration Tool
SDK & Developer Tools
Specifications
Power
Up to 25 V / 3 A solar input
Supports solar panels up to 50 W
3 A protected load output
Low quiscent current
Supports standard 12V batteries and some 9V batteries for types: SLA, VRLA, GEL, Flooded and LiFePO4 packs (with BMS)
Mechanical and Integration
Compact 40 mm (L) x 13.5 mm (W) x 16.5 mm (H) standoff on host PCB
2×10 header footprint (2.54 mm pitch)
Built for host PCB thickness up to 3 mm
Net weight: TBD
Control
Configuration and diagnostics over UART
Automatic and Manual modes
Intelligent MCU-based controller
Basic Control over GPIO
Smart Functions
Photocell mode
Flasher mode
Load force-off input
External NTC temperature input (binary)
Protection
Overvoltage
Overcurrent
Short circuit
Reverse voltage and reverse polarity
Reverse current
Battery depletion and overcharge protection
Hardware-enabled watchdog on MCU
Compliance and Environmental
Tested for FCC Part 15B
CE/UKCA compliance in progress
RoHS
Operating Temperature: –20 °C to 70 °C
Storage temperature: –40 °C to 85 °C
Mechanical Drawing
Ready to Try?
Get SUNMOD03PU on your bench and start evaluating your application without designing a host board first.
The SUNMOD03PU Evaluation Kit makes it easy to configure, test, and evaluate SUNMOD03PU before integrating it into your own hardware. It includes a SUNMOD03PU module, USB-C with driverless USB-to-UART connectivity, current-measurement and functional jumpers, and LED indicators for convenient bench evaluation. It works seamlessly with the SUNMOD Configuration Tool across macOS, Windows, Linux, and compatible Android devices.
Downloads and Resources
Datasheet
SUNMOD03PU Datasheet V1.0
2026-OCT-05
Application Notes
SUNMOD03PU Application Notes V1.0
2026-OCT-05
SUNMOD Integration SDK
Integration SDK for SUNMOD03PU (GitHub Repository)
2026-OCT-05
SUNMOD Configuration Tool
SUNMOD Configuration Web Application
2026-OCT-05
CAD Library
KiCad Symbol and PCB Library V1.0
2026-OCT-05
Note: Some of these photos were taken during actual development and testing—not for publication. We’ve chosen to share them as they are, including the occasional imperfect angle, busy workbench, and unpolished detail.
A Gallery Behind the Product
Designed at the Desk. Verified in the Lab. Proven in the Field.
Real hardware. Real software. Real-world testing.
FAQ
Why SUNMOD03PU instead of an off-the-shelf solar charge controller?
SUNMOD03PU is designed to be integrated directly into your PCB, unlike most standalone solar controllers. It combines configurable charging, protected 3 A load control, UART configuration and diagnostics, and built-in photocell, flasher, and load-control functions. Its hybrid direct/PWM architecture also simplifies integration and EMI considerations compared with many switching converter-based solutions.
Can SUNMOD03PU charge 3.7 V / 4.2 V lithium batteries?
No. Do not connect single-cell 3.7 V / 4.2 V Li-ion or Li-polymer batteries directly to SUNMOD03PU. It is intended primarily for supported 12 V SLA/VRLA/GEL/Flooded and LiFePO₄ battery packs, as well as certain supported 9 V configurations.
How is SUNMOD03PU configured? Are the settings retained?
SUNMOD03PU is configured through its UART interface using a text-based protocol or the SUNMOD Configuration Tool. Settings are stored in non-volatile memory and are automatically applied after startup, so the module can operate independently after configuration.
Does SUNMOD03PU use conventional MPPT?
No. SUNMOD03PU uses a smart hybrid charging method combining direct panel-to-battery connection with PWM clamping when required. For low-power systems up to 50 W, this provides an efficient, compact, and easy-to-integrate alternative without the complexity and EMI footprint of a conventional MPPT converter.
Can I connect a solar panel larger than 50 W?
No. Use a panel within the specified 50 W / 3 A limits. A higher-current panel or power source may repeatedly trigger protection, causing unnecessary thermal stress and potentially reducing module lifetime.
What does the SUNMOD Configuration Tool do?
It provides a convenient graphical interface for configuring, testing, and diagnosing SUNMOD03PU. You can configure battery, panel, load, and flasher parameters, read voltages and fault states, and perform other development and diagnostic operations without manually entering UART commands.
What capacity GEL, Flooded, SLA, or VRLA battery can I use?
With the correct panel and charging parameters, typical 12 V SLA/VRLA/GEL/Flooded batteries from 7.2 Ah to 33 Ah can be practically charged within a day. Larger batteries can also be used, but will require more charging time. For LiFePO₄, we recommend approximately 12 V / 3–9 Ah and do not recommend capacities above 12.8 V / 9 Ah. See Example 2 in the SUNMOD Application Notes for details.
Can you customize the hardware or firmware for our application?
Yes. SUNMOD03PU is designed to support a wide range of applications, but we understand that every product has different requirements. If your needs can be met by modifying the firmware or configuration, we can help with that. If hardware changes are required, we can also develop a customized version for your application.
Behvolt can support the entire process—from requirements and design through prototyping, validation, and production support. Tell us about your application and what you need at contact@behvolt.com.
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