Senior/Staff Firmware Engineer - BMS

About 1X We’re an AI and robotics company based in Palo Alto, California, on a mission to build a truly abundant society through general‑purpose robots capable of performing any kind of work autonomously. We believe that to truly understand the world and grow in intelligence, humanoid robots must live and learn alongside us. That’s why we’re focused on developing friendly home robots designed to integrate seamlessly into everyday life. We’re looking for curious, driven, and passionate people who want to help shape the future of robotics and AI. If this mission excites you, we’d be thrilled to hear from you and explore how you might contribute to our journey. Role Overview We are looking for a cross-functional Firmware / Embedded Engineer to develop and maintain the battery management firmware for a production humanoid robot. In this role, you will own the firmware that monitors, protects, and manages a high-energy lithium-ion battery pack operating under demanding and highly dynamic load conditions. You will work closely with hardware architects, electrical engineers, systems engineers, and test engineers to ensure firmware reliably bridges hardware capabilities and higher-level system requirements across prototype and production platforms. The battery system in a humanoid robot operates unlike most conventional applications. Load transients are severe and unpredictable — peak currents can cause significant bus voltage sag within milliseconds as actuators respond to real-time control policies. The pack must sustain continuous cycling in uncontrolled thermal environments while maintaining cell-level safety and accurate state estimation. There are no established BMS reference designs for this load profile. The ideal candidate reasons from electrochemistry and circuit fundamentals, builds reliable firmware for safety-critical systems, and is comfortable developing novel solutions where existing vendor toolchains and application notes fall short. Responsibilities Develop and maintain BMS firmware including cell voltage monitoring, current measurement, temperature sensing, and protection enforcement across a multi-series lithium-ion pack Implement state-of-charge (SOC) and state-of-health (SOH) estimation algorithms that remain accurate under high-rate transient loads, temperature variation, and cell aging Architect cell balancing firmware (passive and/or active) that manages cell-to-cell divergence during both operation and charging, accounting for the wide SOC excursions typical of this application Responsible for the testing, validation, and verification of initial firmware releases to ensure functionality, reliability, and performance requirements are met Implement pack-level protection logic: overcurrent, overvoltage, undervoltage, overtemperature, and short-circuit detection with deterministic response times and safe- state transitions Design brownout prediction and mitigation firmware — characterize and manage bus voltage sag under peak actuator loading to prevent cascading subsystem failures Develop CAN/CANopen interface firmware for real-time reporting of pack state to the central controller, supporting both cyclic status data and diagnostic/configuration messaging Collaborate with hardware architects to define BMS hardware requirements, sense circuit topology, and protection coordination between firmware and hardware safety mechanisms Implement pre-charge sequencing, power-on/power-off state machines, and coordination with the system-level power distribution architecture Develop production test hooks and end-of-line validation routines for battery pack acceptance, including cell matching verification and impedance measurement Document firmware architecture, interfaces, and assumptions; improve code structure, readability, and maintainability