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A Complete Guide to Abbreviations for Electric Bus Fleets

The electric bus industry is full of abbreviations, and perhaps some of them you may not be familiar with. Don’t worry, you don’t need to have them all memorized! To help you get through the noise and make you look like a true expert we have compiled a list of some of the most frequently used ones.  

Please see them below. Did we miss one? Do let us know in the comments below and we can add it. 

BEBs  (Battery-Electric Buses) – an electric bus that is driven by an electric motor and obtains energy from on-board batteries. 

ZEBs (zero-emission bus) – a zero-emission bus uses electricity to power a battery, a number of companies are manufacturing zero-emission buses that operate without overhead wires. ZEBs include battery-electric buses and Fuel-cell buses. The great advantage of these buses is that they don’t require gasoline, oil changes, or an internal combustion engine. They also don’t emit exhaust. Zero emissions buses can cost hundreds of thousands of dollars less per year than diesel and CNG buses. Generally, there are also fewer moving parts so they are cheaper and easier to maintain. 

TCO (Total Cost of Ownership) – an estimate of the total cost to own a bus from the time of purchase by the owner through operation and maintenance, all the way to the time it leaves the possession. Includes all the expenses such as insurance, maintenance, repairs, service, etc. This is frequently mentioned in discussions about electric buses, as the TCO of electric buses is usually much lower than that of Diesel buses. 

Opportunity charging – otherwise known as on route or overhead charging. This allows you to quickly charge your battery compared to overnight charging which could take up to 6-7 times as long. The advantage is you can use buses with smaller batteries which can be charged along the route, eliminating range anxiety. 

Depot charging – this type of charging usually occurs overnight when the buses are not used for a longer period of time. 

DOD (Depth of Discharge) – an alternative method to indicate a battery’s state of charge. The DoD indicates the percentage of the battery that has been discharged, or drained, relative to the overall capacity of the battery. 

SOC (State of Charge) – the level of charge of an electric battery relative to its capacity. It is the measurement of how much energy is left in a battery. This is equivalent to the fuel level in a gasoline car or diesel bus. 

C-rate – a measure of the rate at which a battery is being discharged, relative to its maximum capacity. 

OCPP (Open Charge Point Protocol) – an application protocol for communication between Electric Vehicle (EV) charging stations and a central management system, also known as a charging station network.

BMS (Battery Management System) – an electronic system that manages a rechargeable battery (cell or battery pack). The main purpose of the BMS is to protect the battery from operating outside its safe operating area, monitoring its state, and calculating secondary data.

CHAdeMO – the trademark name of a quick charging method for battery electric vehicles delivering up to 62.5 kW by 500 V, 125 A direct current via a special electrical connector. This quick charging method started in Japan and is predominantly used in the U.S. and Japan.

CCS (Combined Charging System) – The name of a quick charging method for battery electric vehicles delivering 200kW via a special plug-in electrical connector, or up to 350 kW via an overhead pantograph. The connector is different than a CHAdeMO connector. This quick standard originated in Europe and is predominantly used in Europe and the US.

LMS (Charging Management System) – in an electric vehicle (EV), an LMS controls the charging process.

CPO (Charge Point Operator) – a company operating a pool of charging stations or chargers.   

V2G (Vehicle-to-grid) – A battery electric vehicle can pull energy for the grid for driving, or can supply stored energy to the grid. In this case the vehicle acts as energy storage to support the grid’s needs. 

ICE (Internal Combustion Engine) – an engine that generates motion by the burning of petrol, oil or other fuel with air inside the engine, the hot gases produced being used to drive a piston or do other work as they expand. 

PHEV (Plug-in hybrid electric vehicle) – This electric vehicle combines a gasoline or diesel engine with an electric motor and a large rechargeable battery. PHEVs combine the fuel-savings benefits of hybrids with all-electric capabilities of battery-electric or fuel-cell vehicles.

kW (kilowatt) – a kilowatt is simply a measure of power, or equal to 1,000 watts. This is a unit that is usually used to measure the charging speed of a charger. To visualize it, this unit of power is like the flowrate of water through a pipe. 

kWh (Kilowatt Hour) – a measure of electrical energy equivalent to the power consumption of one kilowatt for one hour. This is a unit usually used to measure the storage capacity of a battery. To visualize it, this unit of energy is like the volume of fuel in a gas tank. 

OEM (Original Equipment Manufacturer) – manufacturer and seller of vehicles, vehicle parts and related services. However, there are also business models where the OEM remains the owner of the battery and only rents it out.

HEV (Hybrid Electric Bus) – this type of electric bus combines a conventional internal combustion engine propulsion system with an electric propulsion system. These types of buses normally use a Diesel-electric power train. 

DC/DC (Direct Current to Direct Current converter) is a category of power converters. In a battery electric vehicle, this system converts high voltage from the battery packs to low voltage. The low voltage powers the vehicle accessories, such as the low voltage batteries, air system, and lighting.  

EVSE (Electric Vehicle Supply Equipment) Includes all components that supply electricity to an electric vehicle, commonly called charging stations or charging docks. This may include transformers and cabling in addition to the charge station itself. They supply electric power to the vehicle and use that to recharge the vehicle’s batteries. 

FCEV (Fuel Cell Electric Vehicles) a type of vehicle that uses compressed hydrogen gas as fuel to generate electric power via a highly efficient energy converter, a fuel cell. They are more efficient than conventional internal combustion engine vehicles and produce no tailpipe emissions. 

Acronyms for all Buses

Now that you’re an expert with the acronyms for electric buses, here are a few more bus acronyms to add to the list. These are applicable to all buses, not only electric. Take a look at the short list below. 

CAN (Controller Area Network) a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each others’ applications without a host computer.

HVAC (Heating Ventilation and Air Conditioning) the cooling, dehumidification, and filtration of the air within the passenger compartment of your vehicle. 

ECU (Electronic Control Unit) any embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a vehicle.

TCU (Telematics Control Unit) the embedded onboard system that controls wireless tracking, diagnostics and communication to/from the vehicles. 

ABS (Anti-lock braking system) a safety anti-skid braking system. Operates by preventing the wheels from locking up during braking, thereby maintaining contact with the road surface.

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