Feature: Electrifying game-viewing vehicles
Ever thought the game-viewing experience would be instantly better without the clatter and fumes of a dieselpowered vehicle? So did Cliff Barker …
The task seemed simple enough. A new ultra-luxurious seven-star game lodge wanted to offer a next-level safari experience for its clients. The solution? Electrically powered game-viewing vehicles. The catch? It had to be done in six months. We visited Barker Performance Products to investigate how they tackled this clean-sheet project and drive the finished product.
No stranger to engineering challenges, Cliff Barker started building his first offroad racing vehicles back in the 1970s and hasn’t stopped building specialist 4x4s. He estimates he has built more than a thousand game-viewing vehicles over the years and it was a long-time client, Cheetah Plains, who approached him requesting that he develop an all-electric vehicle.
THE ENGINEERING CHALLENGE
In addition to his lack of experience in the field, a move to electric power brought a whole new set of challenges. Following detailed study and calculations that included expected vehicle weight, minimum range and required performance, specifications for the electric drivetrain were determined. These accounted for sufficient acceleration and speed to outrun a charging elephant, adequate gradeability to climb a dry riverbank, and it needed to withstand specific operating conditions including rough road vibrations, high ambient temperatures, wading capability and dust intrusion. Local availability of suitable electric motors, batteries, inverters and other components was virtually non-existent and they had to be sourced from abroad. A suitable electric motor was available from an Italian manufacturer, but the company was unwilling to supply in small quantities. Eventually, the same motor was sourced from an American agent, along with battery modules of the type used by Tesla.
ELECTRIC DRIVETRAIN
For ease of maintenance, Cliff wanted to retain as much of the standard Toyota Land Cruiser 70 Series 4,0-litre V6 drivetrain as possible. Using an adaptor plate, the electric motor was mounted onto the standard bellhousing and supported by a pair of brackets that attach to the standard engine mountings.the standard Toyota gearbox, transfer case, propshafts and axles, including ratios, were also retained.
For optimum performance, he calculated that a reduction gear ratio of 3,0:1 would be required. With the second-gear ratio of the standard Toyota gearbox being 2,46:1, he decided that locking the gearbox in second gear would provide an adequate interim solution. However, a single-speed 3,0:1 reduction gearbox was designed to replace the original gearbox. Utilising the same mountings and other attachment points, it is directly interchangeable and will allow the resale of the original Toyota engine and transmission as a complete package to offset the conversion cost. Prototypes of this purpose-built gearbox have been manufactured and are currently undergoing testing.
Most EV batteries are installed at floor level for practical reasons and to lower the vehicle’s centre of gravity. However, this was not considered ideal because of potential dust and water intrusion. Considering the engine compartment is large enough to accommodate both inline and V8 engines, there was space to spare for the electric motor as it does not take up much more real estate than a powerful starter motor once fitted. This enabled the installation of the battery pack on a tray above the electric motor in the engine compartment, an ideal position to provide suitable cooling and protection against damage. Also fitted in the engine compartment is a 12 V battery used to run electrical systems including wipers and lights, the inverter and battery charging point. The standard brake booster was retained but a vacuum pump provides the required boost.
The electric motor is rated at 100 kw and 235 N.m of torque maintained from zero to approximately 3 500 r/min before steadily declining to the 8 000 r/min limit. The lithium-ion battery pack consists of 10 modules from a Tesla Model S battery, which typically uses 16 modules. Each module comprises of 444 individual cylindrical cells, each 18 mm in diameter and 65 mm high. They provide a total battery pack capacity of approximately 46 kwh and a full charge provides a range of around 80 km when game viewing, or 100 km in normal on-road driving. Considering a typical game drive is approximately 30 km, this additional range means a fleet of vehicles does not need to be charged at the same time overnight. This was an important consideration given the limited power available at a remote game lodge reliant on solar power.
SUSPENSION IMPROVEMENTS
In addition to the electric drivetrain, several modifications have been developed by Cliff to enhance the experience. Although the battery pack is fitted in the engine compartment, the unladen front axle load is the same as the original vehicle. A typical load of passengers is considerably lighter than the maximum payload for which the vehicle had originally been designed, so it was possible to soften both the front and rear suspension. Modified leaf springs, complemented by additional
coil springs and specially tuned Koni shock absorbers were made to provide a more comfortable ride for guests. An interesting idea currently undergoing testing is a link-coil design to replace the leaf springs and further improve ride quality.
OTHER REFINEMENTS
To enhance passenger comfort, individual seats replaced the typical benches.the seats are shaped to provide extra lateral support and seat cushion densities optimise comfort, reduce bumping off-road and are heated for early morning or evening game drives. Other thoughtful touches include charging points and storage boxes for cameras, external mountings for cooler boxes and a fold-away table built into the front bull bar.
MANUFACTURING CAPABILITY
Located in the Apex industrial township in Benoni, Barker Performance is a registered motor vehicle builder, with both the Toyota Land Cruiser as well as Land Rover Defender 110 conversions fully SABS homologated. In addition to final assembly, all steelwork is mandrel bent and fabricated in-house before being sandblasted and powder coated. An in-house trim department manufactures seat frames, moulds the specially designed cushions, and cuts and sews the seat covers. Production capacity is 120 vehicles a year with conversions customised to operators’ requirements and carried out on both new and used vehicles.
DRIVING IMPRESSION
I had the opportunity to drive the electrically powered Toyota Land Cruiser development unit, both on- and off-road. Currently being used to finalise the reduction gearbox and suspension, the vehicle appears completely standard with subtle “Electric” badging down the flank. The unique dashboard and instrument cluster are the only clues to the hightech drivetrain. After turning the standard Land Cruiser key to “On” and depressing the accelerator, the EV accelerated smoothly and strongly. The ease of modulating the throttle was quickly apparent, complemented by regenerative braking, which is adjustable but generally set between 25 to 45%. Charging the battery and extending range, re-gen allows single-pedal driving in most situations, further improving smoothness and comfort. Even though the vehicle was unladen, the ride quality was outstanding and would no doubt be even better with passengers.
With four electric game-viewing vehicles already operating reliably and successfully, and further projects in the pipeline, this has the potential to set the standard for silent and environmentally friendly game-viewing vehicles in the future. And Barker Performance Products is on the cutting-edge of this new technology.