Test Engineer

Job Title: Test Engineer, ESS

Location: This role will be based in Sacramento, CA. During the first 3-6 months, the position will be based in our Burlingame, CA headquarters for onboarding before transitioning permanently to Sacramento.

Department: ESS Engineering

Reports To: Senior Manager, Test Engineering

Position Type: Full-time

Peak Energy is the first American venture to advance globally proven Sodium-Ion battery systems as the storage standard for the new era of renewable energy on a resilient grid.

Sodium-Ion is cheap, readily available and safe, making it the leading contender in a rapidly evolving market.

Our leadership team is powered by decades of expertise in scaling gigawatt-level innovation at world-class companies such as Tesla, Northvolt, Apple, Powin, Enovix, Zipline, Solid Power, and Fluence. We are backed by strategic investment and product partners such as TDK Ventures and Eclipse Ventures.

We are a team of engineers, operators, entrepreneurs, and partners driven by a shared ambition to set the new performance standard for renewable energy and grid resilience.

We are looking for a Test Engineer to support our testing and functional verification efforts for our energy storage systems, from battery to power electronics. This role works closely with design and simulation teams to understand risks, develop procedures, set up and run tests, and report on findings that directly inform the design direction of our products.

You will interface tightly with design, simulation, and manufacturing engineering partners across a fast-moving, early-stage energy company. This role sits at the intersection of technical rigor and rapid iteration, with a direct impact on product safety, reliability, and performance.

The ideal candidate is a self-starter who is hungry for knowledge, holds themselves and others to high standards, and brings a get-it-done attitude to every challenge — big or small.
We are open to all levels.

• Lead and conduct comprehensive testing of functional, thermal, electrical (HV/LV), and mechanical systems across our energy storage products
• Develop test strategies, plans, and procedures to evaluate key risks against performance, reliability, abuse/safety, and functional requirements
• Spearhead the design and acquisition of testing equipment and infrastructure
• Collaborate with engineering teams to ensure design integrity and drive improvements
• Analyze complex test data, report findings, and drive system enhancements
• Identify, diagnose, and resolve intricate technical issues during testing
• Perform root cause analysis on system failures and develop corrective and preventive actions
• Drive innovation in testing methodologies and practices
• Interface tightly with design, simulation, and manufacturing engineering partners to inform design decisions
• Maintain detailed records of tests, analyses, and corrective actions; prepare reports and presentations for internal and external stakeholders
• Drive and participate in a culture of rapid prototyping and automation

• Bachelor's degree in Mechanical Engineering, Electrical Engineering, Aerospace Engineering, or a related field
• 1-4+ years of experience in test engineering, preferably within battery storage or renewable energy sectors; includes relevant internships and student group projects
• Strong understanding of electromechanical engineering first principles
• Proficiency in data processing and analysis tools
• Excellent problem-solving skills with the ability to think critically and act decisively
• Strong communication skills with the ability to present complex technical information clearly to both technical and non-technical stakeholders
• Ability to work collaboratively in a fast-paced, dynamic environment
• Proactive ownership mindset with a strong sense of accountability

• Experience with battery systems, energy storage, or power electronics testing
• Familiarity with automated test systems or rapid prototyping workflows
• Background in reliability, abuse, or environmental stress testing

Peak Energy is committed to building a diverse and inclusive workforce. We strongly…