R&D Test Engineer

Mainspring Energy
Menlo Park, CA

Company Overview

Mainspring Energy is revolutionizing power generation with the world’s most flexible and adaptable onsite power generator, the Mainspring Linear Generator. Commercial, industrial, and utility leaders are choosing Mainspring over traditional options like engines, turbines, and fuel cells to quickly and reliably deliver local power for EV charging, commercial facilities, data centers, and grid-scale operations. The Mainspring Linear Generator is fuel flexible, ramps up and down to meet demand, and utilizes a flameless technology with near-zero NOx emissions.

Backed by top-tier investors such as Khosla Ventures, Bill Gates, American Electric Power, and Lightrock, Mainspring designs, manufactures and delivers its products to customers across the U.S. today, and we’re quickly scaling for international expansion.

Inspired by our vision of the affordable, reliable, net-zero carbon grid, Mainspring is rapidly expanding within the $816B global electricity equipment market, and we’re hiring the best talent to meet growing customer demand around the globe. We welcome a broad range of backgrounds, experiences, and talents to bring fresh perspectives and ongoing innovation to our customers.

We are looking to build relationships with people who share our values:

Pragmatic Optimism. Building a new category of world-class power generation requires the optimism of ambition and creativity, balanced with practicality to solve problems efficiently. The challenges that arise are opportunities for growth.

Excellence without Ego. We bring expertise and commitment to creating the best customer experience, from sales to deployment and service, just as we apply deep technical rigor to building and delivering world-class products. We strive for excellence and behave as leaders with the humility to acknowledge our challenges, both collectively and as individual contributors.

Proactive Collaboration. The integration and cross-disciplinary nature of Mainspring’s business requires intentionally seeking out others who bring different skills, perspectives, and priorities. Our culture of inclusion and respect extends beyond our team to interactions with our partners and customers.

More information can be found at

Job Overview

Mainspring is seeking an R&D Test Engineer who likes to solve challenging cross-functional problems with a mix of computational analysis, hands-on engineering, and team effort. In this role, you will design and execute tests on our system, focusing on acquiring and analyzing complex data streams . You will also have the opportunity to operate our Linear Generator and get exposure to the entire system, including mechanical and electrical components, software, and controls. The breadth of this role is perfect for an engineer or researcher who wants to use their advanced experimental and analytical skills in a fast-paced product development environment. We are looking for an ambitious and curious individual excited to work at the interface of mechanical engineering, systems engineering, signal processing , data science, and software.

Responsibilities

  • Collaborate with engineering teams to steer R&D projects through designing and executing experiments and advanced data analysis, including signal processing techniques
  • Work closely with design engineers to test individual components and their interaction with the rest of the system, with an emphasis on designing and implementing robust data acquisition strategies for lab instrumentation
  • Formulate, lead, and facilitate complex data analysis projects, leveraging your expertise in signal processing to extract meaningful insights from raw sensor data
  • Develop and maintain tools and software to enable other engineering teams to efficiently access, visualize, and analyze datasets from the linear generator
  • Provide feedback to improve the performance and reliability of the linear generator, informed by your detailed data and signal analysis

Qualifications

  • Degree in Mechanical Engineering, or similar engineering field
  • Successful communicator, with a "collaborate-first" mindset, who will interface across a range of teams and personalities
  • Experience with Python and/or Matlab, a basic understanding of data structures, and demonstrated experience with signal processing libraries
  • Experience with instrumentation selection, integration and data acquisition systems in an academic or industrial environment
  • Nice to have:

  • Interest in power generation and energy systems
  • Experience designing and executing tests in an industrial or academic environment, specifically involving complex sensor data and signal analysis

$95,000 - $123,600 a year

This position is onsite at our Menlo Park HQ. The salary will be adjusted to reflect local market conditions based on employee location as well as the experience of the employee. Along with the base salary, Mainspring offers pre-IPO stock options + benefits.

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.

In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.

This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.

Posted 2026-04-01

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