The battery-electric Mercedes-Benz eCitaro is an extension of the successful Citaro range, although its frontal appearance is different. In the cab, there is a high degree of commonality. The manufacturer has deliberately made the eCitaro almost identical to its sisters from a driver’s perspective to simplify fleet integration.
Energy is stored in up to 10 modular battery packs. Four are where the engine would otherwise be, with the remainder on the roof. With the maximum number fitted, batteries account for 2,500kg of a GVW of 13,700kg.
The location of those above the saloon can be ‘trimmed’ to optimise weight distribution, and Daimler says that its balanced charging strategy maximises their lifetime. Opportunity replenishment will be offered later if required.
Climate control is managed smartly. A heat pump incorporated into the air-conditioning unit ensures the greatest efficiency, and waste heat from a braking resistor is used in the saloon.
The Mercedes-Benz eCitaro shares Sideguard Assist with the Tourismo. It works on the same basis, with radar detection and a seat-shaker warning; as with the coach, it seems likely that automatic braking will follow later.
Where the eCitaro can slow automatically is via Preventive Brake Assist. Daimler calls it a world first for buses. It warns of frontal collisions, including with pedestrians, and it can engage partial braking. Daimler stresses the ‘partial’ aspect, which takes account of passenger safety.
On the road, the eCitaro drives in a similar way to a diesel Citaro. In place of a tachometer, it has a power gauge. The needle’s default position is 12 o’clock; it moves to the right when charge is taken from the batteries, and to the left when it is returned.
A retarder-style lever forms the right-hand stalk. It activates regeneration, which also engages during the brake pedal’s initial travel.
Most noticeably different from other electric buses is the eCitaro’s behaviour when the accelerator is released. It coasts, with no regeneration until either the stalk or the brake pedal are touched. The distance that it can freewheel is enormous; Daimler says that with a competent driver at the helm, that greatly increases energy efficiency.