There are a number of methods that can be followed to increase the amount of time an electric bus can be operated in service. The first is to perform battery change outs. Many systems, including Chattanooga, regularly swap battery packs. In a span of 10-15 minutes, the bus can be back in service with a fully charged battery.

A second way to increase the amount of time an electric bus can be operated is to "opportunity"charge the batteries during brief, normally secheduled midday layovers (e.g., at bus stops). These recharge episodes are frequently conducted at higher power levels than are applied during conventional, overnight charging in order to maximize the amount of energy returned to the bus during the brief charge opportunities (also referred to as "fast charging"). Some opportunity charging systems incorporate "inductive" coupling hardware that facilitates automatic initation and termination of the charge process, thereby allowing the driver to attend to other tasks. Several opportunity charging research projects are currently underway.

A third method for increasing the amount of time an electric bus can be operated is to purchase advanced technology batteries, such as nickel-cadmium batteries. Although much more expensive than conventional lead-acid batteries, ni-cads can double the range of electric buses and have a longer life span.

An auxiliary power unit (or APU) can also be integrated into an electric bus to achieve improved operating range. By utilizing a second fuel and an engine/generator, electricity can be created that can significantly add to the range of the bus. Electric vehicles that use two fuels are referred to as "hybrids"

Do electric buses have transmissions?

Can cells in a battery pack be replaced?

Is an electric vehicle more energy efficient than an ICE vehicle?

The 22-foot bus, which is the predominant electric bus in operation today, is governed around 45 miles per hour. The 40-foot hybrid-electric bus operating in New York is governed at 55 miles per hour.

It should be noted that "fuel" costs can vary based on battery size and/or the efficiency of the battery charger, and local electricity costs.

There are two primary configurations of hybrid-electric propulsion systems: series and parallel. Both systems utilize an electric motor, a battery or ultracapacitor, and an ICE with generator. In the case of the series hybrid configuration, only the electric motor is mechanically coupled to the wheels; the battery, ultracapacitor, and ICE/generator provide the electricity that powers the motor. In the parallel hybrid configuration, a secondary method of turning the wheels is provided; in addition to making electricity to power the motor by turning the generator, the ICE is almost mechanically coupled to the wheels to enable a more direct traction pathway by bypassing the generator and electric motor. While one approach isn't necessarily better than the other, there are some key differences to keep in mind. Because the ICE is not mechanically coupled to the wheels in the case of series hybrid, it can operate in a more efficient regime and can also be temporarily turned off for all-electric, zero-emission operation. Parallel configurations are typically designed so that the electric motor provides traction at low speeds, the ICE provides the power at higher, constant speeds, and both work together during periods of acceleration.

Plug-in hybrid buses are also under development. As with the hybrids that do not require connection to the electric utility grid, plug-in hybrids have the ability to run on energy stored in onboard batteries and in the fluid fuels that power the ICE. They differ from more conventional hybrids, however, in that they have larger-capacity batteries that can be recharged by connection to the utility grid. Advantages of plug-in hybrids are the potential to operate in quiet, zero emission mode on demand for portions of the duty cycle, reduction in fuel costs resulting from a portion of the refueling being accomplished with relatively low-cost grid electricity, reduced emissions, and the ability to charge-balance battery systems more effectively. Disadvantages include the added weight and higher replacement costs of the larger battery systems.

Energy draw for air-conditioners and heaters is more significant. Therefore, many electric buses do operate the AC and heat through a separate system that is powered by an alternative fuel such as compressed natural gas or propane. There are a number of efforts underway to produce low energy consumption/high efficientcy air-conditioning systems.

Although electric buses are more expensive to purchase than comparable-sized diesel buses, remember that the cost of fueling the bus is significantly less. Additionally, because there are fewer components and daily maintenance is normally limited to batteries, regular maintenance costs can also be lower. Thus, the life cycle cost of an electric bus (including purchase and operating costs) can be equal to or even lower than comparable diesel buses.

 Is special training required for drivers and mechanics?

Maintenance training on electric buses is extremely important. Electric buses are not any more complicated than buses with internal combustion engines, but they are different. An alternative fueled bus utilizes all of the same components as a diesel bus with the exception that the fuel is different ( as well as some fuel delivery components). An electric bus utilizes a propulsion system that is unlike any other motor vehicle. Thus, understanding the unique elements of electric propulsion systems is critical to ensure dependable operation.

 Can electric buses operate up hills?

A charge depleting hybrid utilizes a generator that may or may not maintain the battery state-of charge, depending on the application. Thus, if the bus runs out of the fuel necessary to operate the APU, and the batteries are depleted, the bus will not operate, even if more fuel for the APU is added.

AC and DC motors come in different sizes with different torque curves. As each have different characteristics and advantages, it is important to discuss the types propulsion systems available during the purchase of an electric bus.

And, of course, power plants are not located where people live and work. Additionally, it is easier to scrub for emissions at the relatively low number of power plants then the millions of motor vehicles traveling our streets.

It should be noted that the way the electricity is created will play a major role in determining this percentage. Clearly, power generated from water or wind will result in a 100% reduction in emissions.

And one other point must be made. Power plants which operate on coal or similar types of fuels have made great strides to reduce emissions. It is much easier to maintain and police the few power plants then the millions of cars, trucks, buses, etc., used by the public.

 What is better...conductive charging or inductive charging?

Conductive chargers use the more traditional electrical plug concept.