In spring 2018 a Volvo 7900e battery electric bus was demonstrated on Line A of the Kent Fastrack BRT system.
The bus travelled between the town of Dartford and the Bluewater shopping centre., with each journey stopping off at Greenhithe railway station where the bus had its batteries topped-up using the OppCharge 'opportunity charging' fast charge battery charging system.
Filmed on two visits - with different weather conditions!
More information about OppCharge can be found here:
www.oppcharge.org
Opportunity charging is the term for buses (and maybe in the future other road vehicles too) topping up their onboard stored energy when the opportunity arises. Typically this will be done at the route terminus but on some systems there are additional top-ups at bus stops. Where several bus stops have the required equipment the top-up might even be discretionary, depending on whether the bus really needs it - or not. This already is the situation on a technology demonstration system in Germany where rigid buses need fewer battery top-ups than the articulated buses.
Usually battery buses will receive a full re-charge overnight when they are connected to a charger which also balances the battery cells, this being an action that ensures maximum life of the battery pack.
Mostly buses use batteries for their onboard energy storage but especially in China there are some cities where they use capacitors (of one type or another). The advantage is that capacitors will last the lifetime of the bus (batteries can expect to need replacing after a decade). The disadvantage is that capacitors have a lower energy density, which means that weight for weight
they store less energy, which translates as the bus being able to travel a shorter distance before its onboard energy storage needs topping-up.
In China what are known as 'double electric' buses use batteries for distance energy storage and capacitors for regenerative braking.This is done because capacitors are better able to accept regenerative braking energy than batteries.
The reason why opportunity charging was invented is that to avoid exceeding legally mandated axle weight limits it is not possible for two axle large buses to both carry a full complement of passengers and store enough energy for a full day's duties. Batteries are very heavy plus, as has been found on London's half dozen BYD battery buses, the space required for the batteries reduces the space available for passengers.
Music: On The Cool Side by Kevin MacLeod
Licensed under a CC Attribution 3.0.
incompetech.com/music/royalty...