Battery Software & Controls Integration Engineer, Energy Storage

About Redwood Materials Redwood Materials was founded in 2017 by JB Straubel, co-founder and former CTO of Tesla, on a simple but radical idea: the critical minerals powering the energy transition already exist. They just need to come back. Today Redwood is the largest lithium-ion battery recycler in North America — recovering, refining, and redeploying critical minerals from end-of-life batteries back into the supply chain. On the energy side, Redwood has deployed the largest second-life battery project in the world, delivering power to AI data centers in months rather than years using proprietary energy architecture engineered entirely in-house. The company is profitable, the market it operates in is projected to grow 20 to 50 times over the next decade, and Redwood is the only company with the supply chain, the technology, and the operational scale to lead it. About the Role At Redwood Materials, we are architecting the future of grid-scale energy storage by transforming diverse, second-life automotive batteries and new assets into a unified, software-defined Battery Energy Storage System (BESS). We are looking for a deeply technical, hands-on Battery Software & Controls Integration Engineer who lives at the intersection of electrochemistry, embedded BMS firmware, and high-voltage pack hardware. In this role, you won't just write high-level communication wrappers—you will get your hands dirty in the lab bringing up heterogeneous OEM battery packs off-vehicle, reverse-engineering proprietary BMS architectures, and validating the underlying battery state estimation algorithms. You will evaluate the accuracy of native OEM BMS outputs (SoC, SoH, SoP, cell balancing, and thermal limits) against physical pack behavior, while deploying and integrating Redwood’s in-house battery control and estimation algorithms to extract safe, maximum performance from aged and mixed-chemistry assets. You will also serve as the technical anchor with external automotive OEMs, defining the low-level firmware hooks and safety handshakes required for stationary grid operation. This position is based in our San Francisco office and operates on an onsite work model. Key Responsibilities • Hands-On Pack Bring-Up & Reverse Engineering: Lead physical benchtop and lab bring-up of diverse second-life EV battery packs. Probe wiring harnesses, capture and decode proprietary CAN/CAN-FD/LIN/Ethernet traffic, spoof vehicle-level wake/keep-alive and crash/interlock signals, and command pre-charge and main contactor sequencing to run packs safely off-vehicle. • OEM BMS Algorithm Validation: Design and execute rigorous hardware and HIL test campaigns to audit native OEM BMS algorithms under stationary grid duty cycles. Validate the accuracy of existing BMS state estimations—including State of Charge (SoC), State of Health (SoH), dynamic charge/discharge power limits (SoP), internal resistance growth, and fault thresholds—against true electrochemical and thermal performance. • In-House Algorithm Integration: Implement and integrate the software for Redwood’s proprietary battery state-estimation, degradation-mitigation, and active balancing/derating algorithms (in Rust or C/C++) either atop or in bypass of native OEM BMS telemetry, reconciling discrepancies between legacy automotive logic and second-life pack realities. • Software Gateways & Deterministic Control Interfaces: Architect and deploy resilient, low-latency software abstraction layers and translation gateways on embedded targets that normalize heterogeneous pack telemetry, manage complex fault state machines, and interface seamlessly with our Power Conversion Systems (PCS) and site controllers. • Technical OEM & Supplier Leadership: Serve as the primary technical counterpart to external automotive OE