Battery and Power Systems Engineer

SiFly; Santa Clara (CA); On-site; USD 120,000 - 165,000; Full time

Job summary

SiFly is building a new category of aircraft: vertical-takeoff, long-endurance drones that deliver helicopter-level performance at drone economics. Onsite in Santa Clara, CA, we seek a lead engineer for battery packs and high current distribution.

You’ll own pack architecture, BMS requirements, safety testing, and vendor collaboration for a hands-on role. The role combines bench work, shop floor, and customer-site problem solving with a focus on reliability, safety, and scalable production as

Qualifications

• Electrical engineering depth with high-voltage battery experience.
• You’ve taken a lithium-ion pack from cell selection through to a shipping product.
• BMS electronics experience. Ability to specify architecture options and firmware behavior.
• Hands-on bench capability: instrument a pack, run thermal characterization, interpret data.
• Battery safety test experience.
• You anticipate failure systematically - DFMEA, worst-case analysis, derating.
• First-principles thinking about propulsion, power systems, and radio tech.
• Hands-on role at a small company; bench, shop, flight line, and customer site work.
• You use AI as a real tool and can cite a concrete example of its impact.

Responsibilities

• Drive pack architecture and cell evaluation.
• Evolve pack designs: structure, materials, thermal paths, tolerance analysis.
• Define BMS hardware architecture and firmware requirements.
• Own charger architecture and charge-rate strategy.
• Lead battery safety analysis, testing campaigns, and documentation (UN 38.3, IEC 62133).
• Lead hardware analysis for safety: DFMEA, derating, thermal margin.
• Support Manufacturing, Quality, and Supply Chain through NPI and ramp.

Skills

High-voltage battery

BMS architecture

Cell selection

DFMEA

Thermal analysis

Bench testing

Battery safety testing

AI workflows

Job description

At SiFly, we're building a new category of aircraft: vertical-takeoff, long-endurance drones that deliver helicopter-level performance at drone economics. After thousands of flight tests and years of engineering, our NDAA-compliant platform flies more than 2 hours in hover or 3 hours in forward flight on a single charge - matching the capability of traditional helicopters at a fraction of their cost and operational burden. We merge aerial robotics, perception, and onboard intelligence to cut complexity and minimize human intervention, and our unique approach to communications and networking unlocks remote operations from day one. It's an ambitious mission, and we're a small team that moves fast.

The role

A lead engineer for battery packs and high current distribution in our products. This can include cell selection, architecture, thermal and electrical design, BMS tuning and characterization on the bench. You'll also play a role in cell and pack vendor relationships, our manufacturing partners, and the safety testing and certification.

What you'll do

• Drive pack architecture and future cell evalutions

• Understand and evolve our pack designs including structure, materials, thermal paths, tolerance analysis - and characterize them on the bench.

• Drive BMS hardware architecture, and specify the BMS firmware requirements: what it must do, and how it must fail.

• Own charge control: charger architecture, charge-rate strategy, and the throughput consequences of both.

• Drive battery safety - the analysis, the test campaigns, and the documentation - including UN 38.3 and IEC 62133.

• Lead hardware analysis in support of safety: worst-case circuit analysis, DFMEA, derating, thermal assessment, protection coordination.

• Support Manufacturing, Quality, and Supply Chain through NPI and production ramp.

What we're looking for

• Electrical engineering depth with real high-voltage or high-energy battery system experience.

• You’ve taken a lithium-ion pack from cell selection through to a shipping product.

• BMS electronics experience. Ability to specify architecture options and firmware behavior. History of working with cell monitoring, balancing, protection circuits, isolation measurement.

• Hands-on bench capability: you can instrument a pack, run the thermal characterization, and interpret the data.

• Battery safety test experience

• You anticipate failure systematically - DFMEA, worst-case circuit analysis, derating and stress analysis, thermal margin.

• First-principles thinking and a drive to understand the "why" behind traditional approaches to propulsion, power systems, and even radio technologies.

• This is a hands-on job at a company that is still small. You'll be at the bench, in the shop, on the flight line, and sometimes at a customer site working out why a deployed system is misbehaving - alongside new product development, not instead of it.

• You use AI as a real tool, not a talking point. We want to hear one specific example of something you did with AI that surprised you - a workflow you rebuilt, a problem you came at sideways, an analysis that wouldn't have been worth doing by hand. We care less about which tools you use than about what you've changed about how you work. We're enthusiastic about the leverage and unforgiving about errors.

Nice to have

• Both aerospace and automotive high-voltage battery context.

• Charging infrastructure design, and mechanical pack design alongside the electrical side.

Details

• Onsite in Santa Clara, CA.

• Compensation range $120-165K