Embedded Test Engineer Intern

About the Role Rebaba is building circular battery systems from second-life EV batteries. Our products power buildings, industries, and charging infrastructure while reducing costs and emissions. We design and assemble our systems in Sweden and combine hardware, embedded software, and cloud control into one integrated platform. We are now hiring an Embedded Test Engineer Intern to support the automated validation of firmware and hardware layer that keeps our BESS units running safely and reliably in the field. If you want to get hands-on experience with software that controls real energy infrastructure and see your code make a tangible impact, we would love to hear from you. As an Embedded Test Engineer Intern at Rebaba you will work closely with our embedded and electrical engineers on firmware unit and integration testing, hardware-software integration, and automated test pipleines, having real ownership over features and the quality of the end product. Responsibilities

• Build and maintain automated test pipelines (CI) for the embedded firmware running in our BESS units
• Write unit tests for firmware modules in C/C++ using frameworks such as Unity, CppUTest, or GoogleTest, including mocking of hardware dependencies
• Develop integration tests that verify communication between battery management systems, controllers, and peripherals (CAN, Modbus, RS485)
• Design and run hardware-in-the-loop (HiL) tests, including setting up test rigs, simulating sensor inputs, and verifying actuator and safety responses
• Write test scripts and tooling in Python to automate firmware flashing, test execution, data logging, and result reporting
• Investigate test failures, reproduce bugs on hardware, and work with firmware developers to find root causes
• Document test plans, test cases, and test reports clearly to support compliance, traceability, and future engineers
• Collaborate with the embedded, hardware, and software teams during daily work and design discussions

Requirements

• Currently pursuing or recently completed a degree in Embedded Systems, Electrical Engineering, Computer Engineering, Mechatronics, or a related field
• Experience in Python and C/C++
• Familiarity with software testing concepts such as unit testing, integration testing, and test-driven development
• Some hands-on experience with ESP32 (or similar microcontrollers, e.g. STM32, Arduino) through coursework or personal projects
• Interest in CI/CD and test automation
• Comfortable working across electronics, mechanical, and software teams and translating between them
• A genuine willingness to learn, ask questions, and dig into problems independently
• Strong attention to detail and a methodical approach to finding and documenting edge cases

Meriting

• Basic understanding of, or willingness to quickly learn, CAN bus communication
• Comfortable reading datasheets and debugging at both the code and hardware level (multimeter, logic analyzer, oscilloscope basics are a plus but not required)
• Experience with pytest or a C unit test frameworks
• Experience with Git, GitHub Actions, GitLab CI, Jenkins, or similar

Benefits

• A key role in a fast-growing climate-tech company making real impact
• Ownership of the full software stack as we develop it together
• A close-knit team and a product you can see, touch, and demo with conviction
• A clear path to grow as Rebaba scales - in seniority, responsibility, and scope
• Health and Fitness allowance
• Flexible working hours

About Rebaba Rebaba is at the forefront of sustainable energy storage solutions. We specialize in giving second life to electric vehicle batteries, transforming them into efficient energy storage systems. Our mission is to accelerate the transition to renewable energy while reducing waste and environmental impact.