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Lunar Energy

Senior Firmware Engineer

Become a Senior Firmware Engineer at Lunar Energy in London or Mountain View. Develop and optimize firmware for cutting-edge home battery systems. Enjoy competitive salary, stock options, and flexible working arrangements.

Lunar Energy

Company Overview

Lunar Energy

Mountain View, CA, United States

2020

Approximately 250 employees (source: lunarenergy.com).

What They Do

Lunar Energy is a pioneering renewable energy startup focused on electrifying homes through innovative clean energy products and virtual power plants. The company, founded by Kunal Girotra, a former Tesla Energy executive, aims to provide scalable solutions that allow homeowners to generate, store, and manage electricity efficiently. Their flagship product is a next-generation home battery system, which is part of a modular hardware ecosystem designed to facilitate the transition to 100% clean energy by replacing fossil fuel appliances with solar-compatible technologies such as heat pumps and induction cooking (source: cbinsights.com). Additionally, Lunar Energy integrates its hardware with Gridshare software, acquired from Moixa, to enable smart energy controls and aggregation into virtual power plants (VPPs) that connect thousands of home batteries for grid balancing (source: cleantechnica.com).

Projects & Track Record

While specific completed projects are limited as Lunar Energy focuses on product development, the company has made significant strides in integrating proven technologies from its acquisition of Moixa, which has managed extensive home battery fleets for smart charging and VPPs (source: investors.sunrun.com). The first home battery system was slated for market launch in late 2022, and ongoing efforts are centered on scaling manufacturing and partnerships with Sunrun for nationwide residential rollouts. Lunar Energy's geographical operations include its headquarters in Mountain View, California, and a software hub in London, UK, targeting U.S. residential customers first while eyeing global VPP expansion (source: cbinsights.com). Key clients include Sunrun, which serves as a lead investor and distribution partner, further solidifying Lunar's position in the renewable energy market.

Recent Developments

In the past two years, Lunar Energy has not disclosed any new funding rounds or major contracts following its emergence from stealth in 2022. The company continues to focus on product scaling and commercialization of its VPP solutions, with the 2022 $300 million funding raise and the acquisition of Moixa marking significant milestones in its early development (source: equityzen.com). Although press mentions in 2025 have referenced unrelated entities, Lunar Energy remains committed to its mission of home electrification and expanding its market presence through strategic partnerships and technological advancements (source: investors.sunrun.com).

Working There

Lunar Energy offers a dynamic work environment primarily focused on engineering roles, with approximately 250 employees engaged in hardware, firmware, software, product development, and R&D. The company actively recruits talent for its Mountain View headquarters and London office, emphasizing a mission-driven culture that attracts savvy entrepreneurs and passionate experts (source: lunarenergy.com). While specific benefits are not publicly documented, the company invites applications for various roles, highlighting its commitment to building a high-impact team dedicated to addressing climate challenges through home electrification (source: lunarenergy.com).


Last updated on 2026-02-23 | Report an issue

Lunar is transforming the way we power our homes by building an ecosystem of all-electric products starting with a next-generation home battery system. The Lunar team is made up of savvy entrepreneurs as well as passionate technology and industry experts who build and deploy products to electrify homes, which are connected through an integrated software platform called, Gridshare

We are looking for a Senior Firmware Engineer to join our ambitious, focused and collaborative team of talented developers to build the features the company needs to succeed in its vision.

Responsibilities

These include:

  • Developing the firmware for our hardware devices including optimisation on the edge.
  • Designing, coding and testing sub-systems that provide high performance functionality on constrained hardware.
  • Writing code across the full embedded stack from bootloader to high-level application firmware.
  • Developing platform firmware to support many components like Flash filesystems, communication stack, Build tool management.
  • Developing firmware in a RTOS environment, porting and maintenance of RTOS.
  • Working on components firmware that integrates with other components of our Lunar System.
  • Driving designs and discussion on system architecture to achieve the desired product functionality.
  • Working with a team in design, development, providing code reviews etc.
  • Supporting System test, reliability and manufacturing teams with special firmware features and debugging.
  • Reviewing performance data of the Lunar system from internal and external test sites.

Your required skills

  • 5+ years' experience developing and architecting software, with experience of the full lifecycle from prototype to production.
  • Experience developing C in bare metal systems and/or RTOS.
  • Experience implementing power electronics firmware control functionality.
  • Ability to integrate hardware and software to develop end to end solutions.
  • Happy working in a small, fast moving team, in which your individual initiative and contributions can have a big impact.
  • Contribute in a multi-disciplinary team following modern software engineering practices (e.g. Git, Continuous Integration).

Good to have

  • Familiarity with automated testing tools and debugging methodologies.
  • Experience with battery management systems and AC/DC converters.
  • Ability to read hardware schematics and PCBs.
  • Experience in any of: Rust / Python.

You should be

  • Happy working in a small, fast-moving team, in which your initiative and contributions can have a big impact
  • Willing to travel to and work from the HQ office in California a few times a year

Joining us gives you

  • Competitive salary and stock options package
  • Private Medical Insurance scheme through BUPA (medical history disregarded)
  • A wellbeing and lifestyle benefits plan through Medicash
  • 5% employer contributions pension matching
  • A budget for work related training of ??1,000 per financial year and an allowance of 4 training days
  • Cycle To Work scheme and Workplace Nursery benefit
  • Access to Spill - Mental Health Support platform
  • Enhanced Maternity + Paternity Pay
  • 25 days annual holiday entitlement + 8 Bank Holidays
  • Flexible start and finish times, fully remote working or hybrid depending on preferences

Location

This role is hybrid, it requires you to come into the London office once every week. You will also be required to travel to the HQ in Mountain View, California every quarter. We would also consider candidates that are interested in eventually relocating to California, USA.

We are proud to be an equal opportunities employer and welcome applications from all suitably qualified persons regardless of their race, sex, ethnicity, disability, religion/belief, sexual orientation, gender identity or expression, nationality, age or social background. We would like to actively encourage applications from those who identify with less represented and minority groups. We do not filter applications by university background and encourage those who have taken alternative educational and career paths to apply.

Apply now

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About the role

February 26, 2026

Full Time

Company

February 26, 2026

Hybrid

Energy Storage

Lunar Energy

lunarenergy.com

  •  London, United Kingdom
  •  Mountain View, California, United States

5+ years

UTC+00:00 — UTC-08:00

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