LexSWITCH E12 SD

The LexSWITCH E12 SD is a fully electric, low-floor single-deck city bus model offered by LexBuild. A prototype unit, tailored for the Singapore market with three doors, was unveiled to the public in November 2022.

Background

LexBuild is a Singapore-based transport engineering services provider involved in both rail and road projects, but primarily catering to the local bus industry. Apart from being a coach bodybuilder, it offers workshop services and is a distributor of vehicle parts. The company also builds and sells its own coaches under the LexBuild HOLA model range.

The new electric bus, which carries the LexSWITCH branding, is the first known city bus offered by LexBuild. It joins one of several three-door electric demonstrator buses to have emerged in recent years, alongside the CRRC TEG6125BEV03, Volvo BZL – SC Neustar City and Zhongtong LCK6126EVG.

As for the broader electric bus market in Singapore, the Land Transport Authority (LTA) last procured 60 electric buses in 2018. Having been built with LTA specifications in mind, this bus could be offered to LTA as a trial, in line with LTA’s ongoing efforts to rapidly electrify the public bus fleet. Half of all public buses will be electric by 2030, which is about 3,000 buses.

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Early sightings

Photos of the LexSWITCH E12 SD on Singapore roads were circulated on social media in late-June 2022. The bus carried LexBuild badges and had yet to be registered.

Back then, the bus was painted to be what appeared to be the Lush Green livery of the Land Transport Authority (LTA) public bus fleet, featuring the two-toned silver borders across the front and the side of the bus. The livery however does not feature the SG♥Bus decal and operator logo in the photo, which was taken along Tuas South Avenue 5.

Notable features on the exterior were wingless mirrors in place of traditional mirrors, similar to the Smart-Vision Rearview Cameras trialled on an SMRT Bus in 2019 and featured on the LTA Smart Bus. A 360-degree surround-view camera system was also installed.

More photos and videos of the bus would be shared by LexBuild Motors staff on LinkedIn in October 2022, ahead of the bus’ public showcase the following month.

Public Showcase @ SITCE 2022

The bus was first exhibited to the public at the 2022 Singapore International Transport Congress and Exhibition (SITCE), held from 2 – 4 November 2022. It also received a blue exterior wrap that covered up most surfaces that were previously in Lush Green, and this blue bus was also featured in LexBuild promotional materials.

In an interview with The Straits Times, LexBuild’s group chief executive, Mr Charles Tan mentioned that his company spent close to $1.5 million to design the new electric bus in-house. Components were sourced from various countries, and Chinese manufacturer Wisdom (Fujian) Motor was commissioned to assemble the bus in compliance with LTA specifications.

The prototype unit took about 24 months and nearly S$2 million to develop from scratch.

Overview

The prototype unit showcased at SITCE 2022 is tailored for the Singapore market, with three sets of double-leaf doors (similar to new buses like the Linkker LM312 and CRRC C12) to improve commuter flow. The bus also features 2 wheelchair bays, passenger information display systems, and driver assistance features.

Construction

The bus is built with a stainless steel chassis (SUS Stala Tube EN 1.4062) and lightweight aluminium bodywork (LexBuild Aluminum Series 6082 Body).

The face of the bus is defined by striking lines in the headlights, almost similar to the design of a MAN A22 Euro 6, accompanied by a contrasting shade of black in the middle. The aesthetic is boosted by silver lines outlining the curves on the side body panels. This continues to the rear of the bus, where the arrangement of angled taillamps (HELLA Shapeline) is reminiscent of the Linkker LM312.

Battery & Drivetrain

The electric drivetrain is a Voith Electrical Drive System (VEDS HD), paired with Lithium NMC traction batteries from Forsee Power.

The Voith Electrical Drive System (mode: VEDS HD) connects an inverted portal axle directly to an electric motor. According to Voith, the direct-drive concept (without the need for an additional gearbox) reduces weight and complexity while increasing driveline efficiency through optimized recuperation. VEDS also comes with an accompanying inverter and control software.

Traction batteries supplied by Forsee Power (model: ZEN SLIM) are mounted on the roof, in the rear, and in the floor of the bus. At just 135 mm in height, these extra-thin modular batteries allowed easy integration into the chassis of vehicles while optimizing weight distribution. These use the Lithium nickel manganese cobalt oxides (NMC) chemistry, which is more energy-dense than Lithium iron phosphate (LFP) batteries used on electric buses previously procured by LTA. Battery systems were produced in Zhongshan, China.

Interior

The LexSWITCH E12 is a low-floor single-deck bus, offering step-free access across the entire length of the bus. It features a three-door configuration, with an entrance door at the front, an exit door in the middle, and a second exit door at the very rear of the bus.

LexSWITCH specifications cite a passenger capacity of 24 seated and 58 standing, for a total of 82 passengers.

Present LTA specifications require two wheelchair bays on all new buses, in line with providing for an ageing population. They also offer more standing space, as well as room for unfolded prams. Both wheelchair bays are also equipped with USB charging ports.

The third door area has the last row of seats on a raised platform accessed via a single step. The width of the rear door is 1.2 m, contributing to ease of passenger access.

Passenger Information Display System

LTA specifications also require the provision of Passenger Information Display Systems (PIDS) for commuters. On the LexSWITCH E12, an external and internal LCD display screen is fitted, with additional interior LED displays mounted at the front and rear.

Drivers’ Cab

The LexSWITCH E12 is fitted with an ACTIA dashboard. In place of analogue dials, the dashboard features a digital instrument cluster in the centre, displaying the speedometer, throttle, state-of-charge, and air pressure among other parameters. On the left side of the dashboard, some physical switches have been replaced by a digital touchscreen.

Driver assistance features supplied with the LexSWITCH E12 are largely supplied by TNT Surveillance, featuring a forward- and side-collision warning system, an anti-Fatigue system, and a 360-degree surround-view camera system. The surround-view monitor is positioned to the right of the dashboard, which is less visually intrusive as compared to other buses which have had the system retrofitted onto the dashboard area.

 

The digital mirrors are Smart-Vision Rearview Cameras supplied by Safety Tech, with digitally-processed images having the benefit of compensating for low lighting, shadows and glare. They also improve visibility in wet weather compared to traditional mirrors. Furthermore, the left side mirror can be positioned nearer to the bus driver, improving line-of-sight visibility without obstruction from passengers or the front door.

CCTV monitors and air-conditioning controls are found above the driver’s cab.

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Technical Specifications (Prototype)

Lexbuild commissioned Chinese electric vehicle manufacturer Wisdom (Fujian) Motor Company Limited (also known as Weisheit) to assemble the bus to LTA-compliant specifications. Prior to LexBuild’s acknowledgement of Wisdom Motors’ involvement in a Straits times article, Lexbuild International Pte Ltd was already cited as a customer of Wisdom Motors on the Wisdom Motors website.

Construction

Source material: This local SME has created an electric bus that’s getting global attention | The Straits Times

According to Lexbuild, the bus uses light and durable honeycomb composite materials instead of conventional plywood for its floorboard, and ultralight aerogel instead of foam for insulation. This decreases its weight and energy consumption, and maintenance costs and needs.

To accommodate the batteries’ unusual distribution and other features, LexBuild said it worked with a variety of partners to design a brand-new chassis and other systems and technologies. It is also able to offer the aluminium structure as a knock-down kit for third-party assembly. Lexbuild also claimed that its battery supplier (Forsee Power) developed first-of-its-kind battery modules based on its specifications for the bus.

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Additional Photos

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See Also:

• Linkker LM312 – another model of 3-door electric single-deck bus
• 60 Electric Buses procured by LTA
• Electric Buses in Singapore

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References:

• 威驰腾 (wisdommotor.com)
• LinkedIn Post by Peter Leong
• Made in S’pore: Local bus builders eye slice of electrification pie | The Straits Times
• Singapore Bus Manufacturer LexBuild Chooses Forsee Power Ultra-thin ZEN SLIM For Their New Electric Bus | Business Wire
• This local SME has created an electric bus that’s getting global attention | The Straits Times
• Technical Specifications from LEXSWITCH Brochure @ SITCE 2022