Your Role

We are looking for a skilled and analytical System Test Engineer (m/f/d) to drive system-level validation of our Battery Energy Storage Systems (BESS).

You will help build the foundation of our testing function by defining processes, infrastructure, and tools as production scales. The role focuses on validating complete BESS and key subsystems to ensure functionality, reliability, and safe integration of mechanical, electrical, and software components. Additional tasks may include PLC logic implementation, and development of EoL/FAT tooling.

Your mission

System & Subsystem Testing

• Plan, execute, and document system- and subsystem-level BESS tests.
• Verify integration of electrical, software, thermal, and safety systems.
• Conduct functional, performance, and regression tests.
• Analyze deviations and support troubleshooting and root-cause investigations.
• Develop scalable test procedures and contribute to the long-term testing roadmap.

Building the Testing Function

• Help establish internal testing processes, standards, and tooling.
• Support definition of future testing infrastructure and methodologies.
• Enable knowledge transfer and, over time, support additional testing staff.

Documentation & Compliance

• Maintain accurate test documentation and traceability.
• Support CE/EMC and other certification-related tests.
• Provide structured feedback to engineering teams for continuous improvement.

Additional Engineering Tasks

• PLC Programming: Support PLC logic implementation and communication/I/O configuration.
• EoL/FAT Tooling: Contribute to automated test processes, device integration, and reporting.

Your profile

• Degree in Electrical Engineering, Mechatronics, or similar.
• Experience in testing, validation, commissioning, or troubleshooting complex systems.
• Strong understanding of industrial electrical systems, safety, and system integration.
• Practical skills in PLC programming and/or Python.
• Strong analytical, documentation, and problem-solving skills.
• Optional: Experience with BESS, PLC systems (ideally WAGO).
• Methodical, structured, detail-oriented working style.
• Hands-on mindset and comfort with prototypes and hardware.
• Strong communication and cross-functional collaboration skills.
• Proactive and process-oriented, with interest in shaping a growing testing function.

Why STABL Energy?

STABL Energy is one of the most innovative start-ups in the energy transition, ees Award winner 2022, pv magazine award winner 2025 and named a global Top100 Energy Start-up. We are funded by renowned and experienced Tech VCs from Germany, Denmark and Switzerland.

What you’ll love about working with us:

• Agile, open & innovation-driven culture with flat hierarchies, quick decision-making processes and real ownership
• Company pension scheme to support you plan for the future
• Flexible working hours, a hybrid work model, and the option to work remotely from abroad
• Digital meal vouchers with Circula Lunch - enjoy tasty lunches on us!
• Monthly benefit in kind to spend at your favourite stores
• Corporate benefits portal with exclusive employee discounts
• Regular team-building activities and team events
• Company EGYM Wellpass membership to train with no limits at numerous fitness clubs across Germany Ready to innovate, impact, and inspire? Apply Now!

We’d love to hear from you to help us build the energy system of the future! Even if you don’t meet 100% of the requirements, we encourage you to apply anyway. Our motto is 'Hire for attitude, train for skills', so we value potential and lifelong learning just as much as experience.