--- title: 'R&D Test Engineer at Mainspring Energy' canonical: 'https://feeny.ai/job/r-d-test-engineer-mainspring-energy-menlo-park-3k9wkqbp044e' type: 'job' last_seen: '2026-09-07' --- # R&D Test Engineer at Mainspring Energy - **Company:** Mainspring Energy - **Location:** Menlo Park, CA - **Compensation:** $109k–$124k - **Work type:** onsite - **Posted:** 2026-08-21 - **Last confirmed live:** 2026-09-07 - **Apply:** https://jobs.lever.co/mainspringenergy/bf0521c6-2d3b-47a8-a9c4-0f79db22543b ## Job description Job Overview Mainspring is seeking an open-minded, curious, and highly motivated R&D Test Engineer who likes to solve challenging cross-functional problems in both a research and production environment. In this role, you will design and execute tests on the Linear Generator, focusing on new electrical and software changes that improve product capabilities and performance.You will lead critical sub-system and system-level development and validation tests on new releases of our product and gain exposure to the entire system, including electrical and mechanical 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. ## Responsibilities - Perform hands on work and work directly with technicians to troubleshoot, retrofit, and operate our Linear Generator test units - Collaborate with engineering teams to steer R&D projects by designing and executing experiments that inform product design - Analyze data, generate reports and communicate results with engineering teams to facilitate learnings and design releases - Manage test priorities on a daily basis to meet higher level deadlines with a focus on throughput and completing high value studies - Develop & improve processes and infrastructure to support testing on our next generation products ## Qualifications - Master’s degree in electrical engineering, mechanical engineering, physics, or equivalent with 3+ years of applicable experience - Experience designing and executing tests in an industrial or academic environment, specifically involving instrumentation and data analysis - Successful communicator, with a collaborative mindset, who will interface across a range of teams and personalities - Proficiency in programming with Python/ MatLab/ C++ (at least one) - Strong organizational and project management skills ## About Mainspring Energy ## Company Overview - **One-liner**: Mainspring Energy designs and manufactures fuel-flexible linear generators that provide low-emission, dispatchable onsite power for utilities, data centers, and industrial customers. - **Entity Type**: Private (Series F) - **Headquarters**: Menlo Park, California, United States - **Founded**: 2010 - **Founders**: Shannon Miller ## Core Business - Primary industry: Electric Power Generation - Target customers: B2B – utilities, data center developers, enterprise, industrial - Mission statement: "Redefining how local power is delivered to capacity constrained companies and communities" – enabling clean, reliable, and fuel-flexible power. ## Products & Services - **[Linear Generator (LGen)]**: A flameless, fuel-flexible generator that converts gaseous fuels (natural gas, biogas, hydrogen, propane) into electricity with near-zero NOx emissions. Modular (0.25 MW per unit), fast-ramping (0-100% dispatchable), 46% electrical efficiency (LHV). Standardized 2.5 MW configuration (10 units). Suitable for grid-parallel or grid-independent operation, microgrids, and balancing renewables. ## Market Standing - **Valuation/Market Cap**: Not disclosed (private company) - **Key Metrics**: Annual revenue $117M (latest fiscal year); total funding $813M; 407 employees - **Notable Investors/Partners**: General Catalyst (led Series F, 2025, $258M), Lightrock (led Series E, 2022, $140M), BloombergNEF (grant), and others. - **Growth Signals**: Powering the largest U.S. EV truck charging depot; >1 GW of capacity trusted by Fortune 500 companies and utilities; headcount growing +3.4% YoY; job postings up +121.4% YoY (62 active openings); recently expanded into data center market. ## Competitive Advantages - **Fuel Flexibility**: Single generator can seamlessly switch between natural gas, RNG, hydrogen, and propane without hardware retrofits. - **Near-Zero Emissions**: <1.5 ppm NOx (0.05 lb/MWh) – meets stringent air quality standards. - **Dispatchability**: 0-100% load following, grid-independent operation, capable of firming renewables. - **Low Maintenance**: Only two moving parts, no oil changes, modular design reduces downtime. - **High Efficiency**: 46% electrical efficiency (LHV) across all scales. - **Fast Deployment**: Factory-built, skid-mounted units enable rapid installation. ## Strategic Focus - Scaling manufacturing and deployment to meet growing demand from data centers and utilities. - Advancing hydrogen and biogas compatibility to support long-term decarbonization. - Expanding standardized 2.5 MW configurations to lower installed cost and accelerate timelines. - Building a diverse, cross-disciplinary team to drive innovation in power generation. ## Why Work Here - Culture of inclusion, respect, and collaboration across engineering, operations, and field teams. - Emphasis on growth: "We invest in your growth because progress requires people who keep getting better." - Hybrid/Remote options: headquarters in Menlo Park, manufacturing facilities, and remote field service roles. - Active hiring across engineering (mechanical, electrical, software), operations, supply chain, and field service. - Competitive salary ranges (e.g., Engineer ~$107k, Controls Engineer ~$109k, Manufacturing Engineer ~$91k) plus benefits. - Diverse talent origins from Tesla, Stanford, Apple, SunPower, and other top clean energy companies. ## Sources 1. [mainspringenergy.com/company](https://www.mainspringenergy.com/company) 2. [mainspringenergy.com/careers](https://www.mainspringenergy.com/careers) 3. [jobs.lever.co/mainspringenergy](https://jobs.lever.co/mainspringenergy) 4. [linkedin.com/company/mainspringenergy](https://www.linkedin.com/company/mainspringenergy) 5. [mainspringenergy.com/product](https://www.mainspringenergy.com/product) ## Other roles at Mainspring Energy - [Senior Package R&D Technician](https://feeny.ai/job/senior-package-r-d-technician-mainspring-energy-menlo-park-p5bhgn8zstg3) — Menlo Park, CA - [Electrical R&D Technician](https://feeny.ai/job/electrical-r-d-technician-mainspring-energy-menlo-park-v6xqfjjj185n) — Menlo Park, CA - [Field Service Manager](https://feeny.ai/job/field-service-manager-mainspring-energy-menlo-park-4r34cp3e1w3x) — Menlo Park, CA - [Senior DevOps Engineer](https://feeny.ai/job/senior-devops-engineer-mainspring-energy-menlo-park-5k0yq2053sz8) — Menlo Park, CA - [Manager, Technical Writing Team](https://feeny.ai/job/manager-technical-writing-team-mainspring-energy-menlo-park-yts3j77w15xc) — Menlo Park, CA - [Senior Software Engineer in Test](https://feeny.ai/job/senior-software-engineer-in-test-mainspring-energy-menlo-park-w2wmp8mnhv03) — Menlo Park, CA - [Senior R&D Reliability Technician](https://feeny.ai/job/senior-r-d-reliability-technician-mainspring-energy-houston-5rj77bqr2jp9) — Houston, TX - [Staff Supply Chain Project Manager](https://feeny.ai/job/staff-supply-chain-project-manager-mainspring-energy-remote-rendybj0xsv9) - [Staff Electrical Engineer, Electronics Design](https://feeny.ai/job/staff-electrical-engineer-electronics-design-mainspring-energy-menlo-park-4zzzyqt83v2e) — Menlo Park, CA - [Senior Electrical Engineer, Electronics Design](https://feeny.ai/job/senior-electrical-engineer-electronics-design-mainspring-energy-menlo-park-8f4mvzwnrbfe) — Menlo Park, CA