About The Client
TrendSolar is a U.K.-based renewable energy company providing solar solutions for off-grid users in developing countries. Since 2015, they have designed and financed systems ranging from 70Wh home units to 32kW mini-grids, empowering communities with sustainable energy and connectivity.
Business Context
TrendSolar partnered with ITR to develop a Pay-as-You-Go (PAYG) solar system that delivers affordable, accessible energy and Internet connectivity to low-income communities.
At the core of this solution is a solar box device equipped with a battery that stores energy converted from solar panels, ensuring continuous power supply. To streamline user payments and accessibility, the system includes an Android smartphone with a custom OS and a default app that enables seamless PAYG transactions. Additionally, a web portal provides TrendSolar with real-time insights into device performance, usage patterns, and payment tracking, ensuring efficient operations and customer management.
Project Scope
ITR developed a Pay-as-You-Go (PAYG) solar system for TrendSolar, integrating hardware, firmware, mobile apps, and cloud services.
- Hardware: Solar Box with MPPT charging, battery management, BLE connectivity, LCD & keypad, and flash storage for usage data.
- Firmware: Token-based access control, real-time battery monitoring, and remote power management.
- Mobile Apps:
- Customer App (Android) for device setup, payments (M-Pesa, Tigo Pesa), and usage tracking.
- Agent App (Android) for user registration, activation, and support.
- Cloud & Web Portal:
- APIs for token validation, mobile payments, and device monitoring.
- Web portal for admin control over devices, payments, and customer accounts.
Solution Overview
End-to-End IoT Architecture
The TrendSolar PAYG system integrates hardware, firmware, mobile applications, and cloud services for seamless energy access and remote management.
At its core, the Solar Box stores and distributes power, featuring an MPPT charging controller, battery management system (BMS), and Bluetooth Low Energy (BLE) module for communication with the Customer App.
The firmware enables secure token validation, real-time energy tracking, and remote power control. It also supports Over-The-Air (OTA) updates, allowing TrendSolar to deploy security patches and performance enhancements remotely, keeping devices up to date in the field.
Users manage their energy access via the Customer App, which connects to the Trend Cloud backend via GPRS or SMS for token purchases and usage tracking. The Trend Cloud handles payment processing, token generation, and device monitoring, with a web portal providing administrators real-time insights into device status and customer activity, ensuring efficient remote management.
Local-friendly Payment Method
To make payments easy and accessible, the TrendSolar system is integrated with local mobile money services like M-Pesa and Tigo Pesa, which are widely used in African countries. This allows users to pay for energy directly from their mobile phones without needing a bank account.
When a user adds funds through M-Pesa or Tigo Pesa, the Trend Cloud system processes the payment and sends a secure energy token to the Customer App via the Internet or SMS.
Real-Time Monitoring & Remote Management
The Solar Box continuously collects and logs data, including power usage, battery status, and device health metrics. This data is transmitted to Trend Cloud via the Trend Customer App, which synchronizes logs over GPRS or SMS, ensuring reliable data updates. The firmware’s onboard flash memory can store up to 11 years of usage data under optimal conditions, providing a redundancy mechanism in case of network downtime.
The Trend Web Portal offers real-time insights into device performance, allowing administrators to track active subscriptions, analyze user energy consumption trends, and automate system alerts for bad battery conditions or non-payment lockouts. The backend system supports over-the-air (OTA) firmware updates, enabling seamless deployment of performance optimizations to Solar Boxes in the field.
Business Value
With a fully integrated IoT ecosystem developed by ITR, this PAYG solar solution simplifies deployment, automates revenue collection, and enhances remote management. It empowers TrendSolar to deliver affordable, sustainable power to underserved communities worldwide.
Technologies
Cloud:
- Google Cloud Services
- Databases: MySQL, Redis
Web technologies:
- HTML/CSS/JavaScript
- CodeIgniter
Mobile technologies: Native Android Development
Firmware development: C/C++
PCB design: Altium Designer
