Ray Espinoza
San Jose,CA
Summary
Hands-on battery and energy storage specialist with 6+ years spanning residential solar storage, custom UPS systems, second-life EV repurposing, and autonomous vehicle platforms. Assisted Building and multiple BESS from the ground up - including a 1,000kW+ containerized system- and supported high-voltage AV battery systems at Zoox (Amazon) with Hazardous Voltage Level 4 certification.
Overview
2
2
Languages
1
1
Certification
7
7
years of professional experience
Work History
High Voltage Battery Technician
Fortescue / WAE - contracted to Zoox
03.2025 - 05.2026
- Completed Hazardous Voltage Level 4 certification through Avonside Safety Management - authorizing solo high-voltage work in live battery environments with full arc flash PPE (40 Cal suit).
- Served as Person-in-Charge (PIC) for daily HV operations: establishing safety barriers, controlling site access, enforcing lockout/tagout, and completing daily safety mitigation assignments.
- Performed fleet-wide rework of Zoox AV battery packs - systematically replacing fuse trays in the HVJB (High Voltage Junction Box) across multiple units, requiring precise disassembly, component replacement, and reassembly to spec.
- Conducted voltage, resistance, and hipot testing using Hioki precision testers to verify electrical integrity before pack sign-off and return to Zoox for vehicle integration.
- Performed thread repair/rethreading, silicone reinstallation, module replacement, busbar and fuse service, and cooling system pressure testing to ensure zero-leak certification before shipment.
- Deployed on-call to emergency field sites including Foster City, San Francisco, and Las Vegas to assess and resolve battery system failures in live Zoox AV environments.
- Assisted end-of-line testing and provided final technical sign-off before battery packs were returned to Zoox and installed into autonomous vehicles.
- Contracted to Zoox (Amazon) for high voltage battery technician services.
Electrical Technician
Relyion Energy Inc
01.2024 - 03.2025
- Joined as the company's first technician, promoted to Lead Technician as the team scaled - overseeing technicians and serving as primary technical liaison to systems and mechanical engineers.
- [Project 1] - Medical UPS (Fresno Children's Clinic): Built a custom UPS from scratch using refurbished Nissan EV cells - constructing the cell framework, connecting cells via copper busbars, and integrating a BeagleBone microcontroller with relay banks, capacitors, resistors, and a custom Relyion Nissan Monitoring V3 PCB for charge management and cell balancing.
- Delivered system to a Fresno children's clinic for 24/7 backup power for life-critical refrigeration units storing medicine and medical devices.
- [Project 2] - 720V Second-Life BESS: Designed and built a second-generation BESS using repurposed Kia EV packs (8 modules, ~320V nominal) - disassembled full EV packs sourced from dealerships, harvested and tested individual cells, and integrated 18 batteries with 2 BMS units and updated control architecture.
- [Project 3] - 1,000kW+ Containerized BESS: Engineered and commissioned a 1,000kW+ containerized BESS across two climate-controlled shipping containers - housing 78 LG Chem 6.5kWh lithium-ion modules across multi-shelf rack systems.
- Integrated dual controller panels, 6 BMS units, HVAC thermal management, rooftop cooling, temperature sensors, transducers, fire alarm, communications antenna, and distribution panels with breaker protection.
- Performed busbar fabrication, wire crimping, labeling, conduit routing, and circuit landing - co-executed full build with one colleague from empty containers to commissioned system.
- A company focused on energy solutions, specializing in battery systems.
Apprentice Electrician
Semper Solaris
09.2021 - 12.2023
- Installed Tesla Powerwall, Enphase, and other residential battery storage systems - including multi-unit configurations (up to 8 batteries) for high-capacity residential customers.
- Installed EV charging stations (Level 2) in residential settings, running dedicated circuits, mounting hardware, and commissioning chargers to manufacturer specs.
- Upgraded main and sub-panels, installed load centers, inverters, disconnects, and conduit systems to NEC code requirements.
- Interpreted blueprints, schematics, and work specifications - coordinating with engineers on panel sizing and load requirements for solar + storage systems.
- Tested and commissioned complete residential solar + battery systems end to end including continuity, voltage, and amperage verification.
- A company specializing in solar energy solutions and electrical services.
Apprentice Electrician
Swift Voltage Inc
07.2021 - 11.2021
- Ran circuits to panel boards, bent conduit, installed light fixtures, upgraded panels, installed outlets, and set up junction boxes per NEC code.
- Diagnosed electrical faults using voltmeters and multimeters across residential and light commercial projects.
- A company providing electrical services and solutions.
Battery Technician
ALONGI BROTHERS INC
10.2019 - 07.2021
- Diagnosed automotive electrical system faults - testing battery capacitance, continuity, and component-level failures for emergency roadside and at-home service calls.
- Provided battery replacement and warranty services while completing IBT Electrical Trainee Program concurrently.
- A company specializing in automotive electrical services.
Education
High School Diploma -
Los Banos High School
Los Banos01.2014
Electrician Course Certification -
Institute For Business And Technology
Santa Clara, CASkills
- Live High voltage
- Low Voltage Wiring
- Power tools operation
- Electrical troubleshooting
- Battery storage
- Battery testing
- pack module replacement
Certification
- State of California Electrical Trainee (ET) certification
- Hazardous Voltage Level 4
Languages
English
Native or Bilingual
Spanish
Native or Bilingual
Work Availability
monday
tuesday
wednesday
thursday
friday
saturday
sunday
morning
afternoon
evening
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Timeline
High Voltage Battery Technician
Fortescue / WAE - contracted to Zoox
03.2025 - 05.2026
Electrical Technician
Relyion Energy Inc
01.2024 - 03.2025
Apprentice Electrician
Semper Solaris
09.2021 - 12.2023
Apprentice Electrician
Swift Voltage Inc
07.2021 - 11.2021
Battery Technician
ALONGI BROTHERS INC
10.2019 - 07.2021
High School Diploma -
Los Banos High School
Electrician Course Certification -
Institute For Business And Technology