Battery Systems for Electric Transportation
Proterra's modular Onyx battery platform gives transit bus OEMs the
energy, durability, and domestic content to keep zero-emission fleets
running route after route, from city buses and airport shuttles to regional
coaches.
Why Transit Is Built for Electrification
Fixed routes, published schedules, and a depot every night. Transit's operating model
makes it one of the most natural fits for battery-electric power, and agencies across North
America already know it.
Fixed Routes, Predictable Energy
Known routes and schedules mean energy use can be modeled precisely, so OEMs can size batteries with confidence instead of
guesswork.
Depot Charging Built In
Buses return to the same depot each night for overnight charging, with on-route top-ups at layovers when longer blocks require it.
Stop-and-Go Is Where Electric Wins
Regenerative braking recaptures energy at every stop, so urban duty cycles, where diesel is least efficient, are where electric drivetrains shine.
Cleaner Air Where People Live
Zero tailpipe emissions on busy streets, at curbside stops, and inside terminals, right where riders, operators, and neighbors breathe.
A Quieter Ride
Smooth, near-silent operation improves the experience for passengers and operators and reduces noise in the neighborhoods buses serve.
Lower Operating Costs
No oil changes, fuel filters, or exhaust aftertreatment, and less brake wear thanks to regen. That means more buses in service and fewer in the shop.
Engineered for the Demands of Daily Service
Transit buses rack up high daily mileage, carry passengers in every climate, and need to stay in
service for years. Every Onyx pack is designed, tested, and built in-house to meet that standard.
Transit challenge
How Onyx responds
High mileage, long service life
Designed to deliver 8 to 10 years of reliable power per pack.
Roof, underbody, and compartment packaging
Flat Onyx Slate and compact Onyx Strata variants give OEMs flexible mounting options, from roof and below-frame placements to tighter compartments.
Passenger safety
Cell-level passive propagation resistance. Tested and certified to meet or exceed UN38.3, ECE R100.03, and SAE J2929.
Summer heat to winter cold
Active thermal management with integrated liquid heating and cooling keeps cells in their optimal range.
Uptime and maintenance
Embedded BMS with module-level diagnostics, no external control box, and serviceable fuses, contactors, and controllers.
FTA Buy America
Manufactured in South Carolina and Buy America compliant, helping OEMs meet domestic-content requirements for federally funded buses.
Testimonials
Proterra employees ride a Proterra Powered Transit Bus
Powering Partnerships - Proterra & ENC
Your Electrification Partner
A Partner From First Design to Aftersales
Electrifying a bus platform is an engineering program, not a parts order. Proterra's team works alongside yours at every stage.
01
Vehicle Design & Consulting
Battery solutions tailored to your platform and duty cycle.
02
Integration & Controls
High-voltage system design and integration with your engineers.
03
Prototype & First Build
Hands-on support for a seamless first integration.
04
Validation & Launch
Review of your Design Validation Plans so packs perform as intended.
05
Marketing & Sales
Support as you promote and sell your Proterra-powered buses.
06
Service & Aftersales
Parts, service, and support long after launch.