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Series-ER: Electric-range hybrid
Zero-emission travel where and when you need it

Electric without the worry

Using the same components from our Series-E hybrid-electric system, we have developed Series-ER to extend the electric travel time and distance without the worry of charging, without investing in non-standardized charging infrastructure, without taking power off the grid, and without decreasing the number of passengers on board when adding extra battery packs.

Recently, San Francisco Municipal Transportation Agency (SFMTA) set up zero-emission zones or green zones using Series-ER paired with geofencing technology. The green zones — nine in total — are located in population-dense neighborhoods most affected by air pollution. Each of the zones have a large presence of traffic that is contributing to a high rate of air pollution

Series-ER components diagram
Series-ER components

Series-ER is more electric and practical

  • Series-E with a larger battery
  • Same proven drive components
  • Up to 35% daily EV miles
  • No range challenges – no charging infrastructure required
  • Operationally adaptable
  • One step closer to fully electric

Electric drive modes

Series-ER extends the electric driving range and provides electric operating modes such as:

  • Extended EV range: Driving on all-electric power in no- or low-emission areas can be programmed according to each transit agency’s specifications, to shut the engine off in a tunnel or other preferred areas.
  • Electric accessories: Our Accessory Power System options can power all conventional electric loads, such as cooling fans and pumps, plus all hybrid cooling systems.
  • Stop/start technology: With bus accessories powered by the Accessory Power Systems (APS), the engine can be shut off at stops to prevent idling and emissions. Our stop/start function can be programmed with a global positioning system to automatically shut down the engine at specified locations.
  • Depot drive: The engine can be shut down in specified locations to allow for electric drive mode in low- and no-emission areas, when traveling < 500 yards.

Our series hybrid system

  • No mechanical link between the diesel engine and the axle
  • All power comes from the electric motor
  • Power flows in series from engine to generator to traction motor
  • Adaptable to all electric
Our series hybrid system

Complete integration & support

BAE Systems provides our customers with the most comprehensive power and propulsion systems integration and support in the industry. While others often just ship their system parts to prime bus manufacturers to install, we've sent a certified Application Engineer along with our cutting edge power systems to make sure they are integrated properly from day one, including on-site technical advice and thorough training. Then we back that work with our Flexible Service Plan – customized to fit the customer's business model – including a coordinated spares management program.

  • 35' - 40' North American buses; 12 - 18m European buses
  • 60' articulated buses
  • Double deck buses
City bus diagram and rendering
Articulated bus diagram and rendering
Double decker bus diagram and rendering