Senior Product Engineer

ON.energy is building the power infrastructure that makes the AI era possible. As AI demand surges past what the grid and traditional data centers can support, ON.energy provides a new class of power technology proven at gigawatt scale and trusted by the world’s leading cloud and AI companies. Our systems are already deployed across 2.5 GW of hyper-scale campuses, validated by top U.S. national labs, and certified for grid-safe operation by major utilities. With real products in the field, we’re scaling faster than the grid can, transforming power from a bottleneck into a competitive advantage for the companies building the future.

Role Overview

We're looking for a Senior Product Engineer to own the technical design, specification, and continuous improvement of our BESS and DC Cabinet product lines. This is a product role at its core: you'll author technical specifications, drive vendor engagement, perform detailed component sizing, and partner with project, commissioning, and O&M teams to close the loop between field experience and product design. You should have lived through full product development cycles and know how to bring engineering discipline into a fast-moving environment with frequent release cycles.

What You’ll Do

Product Definition & Specification

Author and maintain detailed technical specifications for the BESS and DC Cabinet — electrical, mechanical, environmental, and interface requirements.

Review and approve detailed engineering drawings: SLDs, GAs, schematics, wiring diagrams, panel layouts, mechanical drawings, and BoMs. Own the technical change baseline.

Perform in-depth component sizing: fuses, busbars, cables, contactors, disconnects, protection coordination, short-circuit and arc-flash inputs, and thermal sizing of cabinets (forced air / HVAC, natural convection, hot-spot analysis, derating).

Vendor & Supply Chain Engagement

Lead technical engagement with key vendors — particularly on the DC Cabinet — driving specs into RFQs, evaluating vendor designs, running design reviews, and resolving issues through prototyping, FAT, and serial production.

Qualify alternate suppliers and own the technical side of dual-sourcing and cost-down decisions.

Product Development

Drive iterative product development cycles with the development team, balancing speed with the rigor expected of mission-critical hardware.

Capture design feedback from design reviews, commissioning, and O&M, and convert it into prioritized changes on the product roadmap via a structured ECR/ECN process.

Run trade studies on architecture and component selection where it matters — cost, reliability, lead time, performance.

Project & Commercial Support

Support business development with technical proposals — SLDs, GAs, and SOC analysis across multiple market applications.

Compile and own the product technical information package handed to project engineering.

Co-lead review and validation of BESS- and DC Cabinet-related topics during project execution.

Maintain as-built drawings and the engineering document baseline.

Participate in commissioning, particularly for first-of-kind deployments, and bring lessons learned back into the product.

Required Qualifications

Bachelor's degree in Electrical Engineering, Power Electronics, or a closely related technical field.

6+ years of hands-on engineering experience in BESS, power electronics, UPS, or comparable mission-critical / industrial power systems, with clear evidence of ownership through full product development cycles.

Proven product or system-level design experience on MWh-scale BESS or equivalent DC power equipment.

Demonstrated experience taking a product through the full development cycle — concept, prototype, FAT, field deployment, revision — in an environment with frequent release cycles.

Strong, demonstrable skill in detailed component sizing: fuses, cables, busbars, protection devices, and thermal sizing for enclosed cabinets.

Fluency producing and reviewing SLDs, GAs, schematics, and panel layouts; comfortable in AutoCAD or equivalent E-CAD tools and reading mechanical drawings.

Track record of running technical vendor relationships through design, FAT, and post-deployment.

Excellent written communication — specs, design reviews, change notices — and the ability to translate between engineering, project, and commercial teams.

Willing to travel up to 20%.

Preferred Plus

Experience with data center / UPS / mission-critical power or utility-scale BESS.

Familiarity with UL 9540 / 9540A and NFPA 855, plus the relevant codes for your target market.

Experience with PLM tools and structured ECR/ECN workflows.

For US-based roles - What you’ll get:

Competitive salary + annual performance-based bonus eligibility

Medical, dental, and vision insurance

401(k) with company match

Paid time off and company holidays

For Mexico-based roles - What you’ll get:

Competitive salary + annual performance bonus eligibility

Christmas Bonus (Aguinaldo): 30 days

Major medical expenses and life insurance

Paid time off and holidays (per local policy)

For all roles:

Professional development and growth opportunities

Opportunity to grow with a mission-driven team shaping the future of clean energy

Equal Opportunity: ON.energy is committed to equal employment opportunity and to maintaining a work environment free of harassment, discrimination, or retaliation.

Accommodations: If you need an accommodation during the application process, email recruitment@onenergystorage.com

Benefits vary by role and location and are subject to change.