Senior Embedded Software Engineer, BMS Firmware

About P6

P6 is a founder owned battery engineering company in Zagreb. The founders spent a decade shipping battery systems in automotive before building P6 to bring that discipline to markets that rarely get it. We design and deliver battery packs across the full lifecycle: concept and cell selection, mechanical and electrical design, BMS hardware and software, validation and certification testing, and series production, for customers in drone and UAV, robotics, defence and industrial markets.

The role

We are expanding our BMS engineering capacity for new series production programs. You own BMS firmware at P6: architecture, core algorithms, communications, safety and integration, through to production flashing and EOL support. Firmware goes from bench bring up through validation readiness to series production in the thousands of units. You work closely with the hardware, systems and validation teams.

What you will do

• Design and implement BMS firmware: measurement, balancing, protection state machines and diagnostics (ARM Cortex-M class MCUs, bare metal or RTOS).
• Develop battery state estimation (SOC, SOH, SOP) and thermal management logic.
• Implement CAN communications, bootloaders, and production and field diagnostics.
• Implement safety mechanisms aligned with the system level safety concept.
• Build unit and integration tests, HIL setups and continuous integration; manage releases.
• Support pack validation, certification testing and production line bring up (flashing, EOL sequences).
• Learn to use Napolitanke as the ultimate colleague bribing mechanism.

What we look for

• 3+ years of professional experience in embedded C on ARM Cortex-M class MCUs, bare metal or RTOS (FreeRTOS or similar).
• Firmware taken to production or field deployment.
• CAN communication protocol experience.
• Structured testing practice: unit tests, integration tests, test automation.
• English good enough to defend a design in front of a customer.

Bonus points

• Experience in battery, power electronics or automotive domains.
• Battery state estimation work (coulomb counting, OCV methods, Kalman filtering).
• Python tooling for test automation and data analysis; MIL/SIL/HIL workflows.
• Formula Student accumulator or BMS background.

What we offer

• Gross annual salary: EUR 40,000 to 55,000, depending on experience.
• 25+ days of annual leave.
• Hybrid work in Zagreb: lab and workshop presence for hardware and integration work, flexible otherwise.
• Full design ownership from concept to delivered pack, on international programs across drone and UAV, robotics and industrial markets.
• No corporate perks yet: no gym membership, no fruit basket, no branded hoodie. That budget goes into lab equipment and the salary range above. There is coffee, and sometimes there is burek for birthdays.

How to apply

• Send us your CV and the thing you have done that you are proudest of to [email protected], subject “Senior Embedded Software Engineer”. Applications in English or Croatian. We look forward to your application, even if you do not meet every requirement.