Overview
A personal engineering project exploring how photovoltaic production, power electronics and battery storage come together into a single working energy system, from design through construction.
Context
During our 20-day scout summer camp, we stay in a remote meadow without access to the electrical grid. Charging phones, powering lights, and running speakers usually required regular trips outside the campsite.
To solve this problem, I decided to build an autonomous solar power system using a discarded e-bike battery and custom-built power electronics.
Problem
Solar production is intermittent, so making effective use of it requires power electronics that can convert and condition the energy, combined with a battery management strategy that safely stores and releases it when needed.
Goal
Design and build a small off-grid energy system capable of powering the camp throughout the entire summer camp while being recharged by solar panels.
What I've Done
I started by disassembling an out-of-service e-bike battery and testing the individual lithium-ion cells to assess their condition.
To rebuild the battery pack, I built my own spot welder using parts recovered from a microwave transformer and assembled a new battery pack equipped with a Battery Management System (BMS).
I then integrated buck and boost converters to provide the different voltages required by the camp equipment and added solar panels connected to an MPPT charger to maximize the charging efficiency.
The complete system was installed on the campsite and operated as a standalone power source for the duration of the camp.
Results
We were fully autonomous in electricity for the entire 20-day camp.
The system reliably powered lighting, charged phones, and supplied energy to speakers and other small devices without requiring any connection to the electrical grid.
Tools & Technologies Used
- Lithium-ion battery testing and battery pack assembly
- Custom-built spot welder
- BMS integration
- Buck and boost converters
- Solar panels and MPPT charger
- Power electronics and DC energy systems
What I've Learned
This project gave me hands-on experience with battery technology, power electronics, and off-grid energy systems.
I learned how to test and reuse lithium-ion cells, build a battery pack from scratch, design power conversion systems, and integrate solar charging to create a reliable autonomous energy solution using recycled components.