E-Mobility Engineering 019 | In conversation: Stephen Lambert l WAE EVR l Battery case materials focus l Quality control insight l Clipper Automotive Clipper Cab digest l Optimising battery chemistries insight l Powertrain testing focus

May/June 2023 | E-Mobility Engineering 57 be unbolted and lifted off the chassis, and all the powertrain components that need to be replaced are attached to the chassis. With the body off, Clipper Automotive takes the opportunity to inspect the chassis for corrosion, repair it if necessary and renew anti-corrosion treatments. Replacing any worn items in the suspension, such as dampers, springs and bushings, is alsomuch easier and quicker with the body removed. Behind the wheel Driving the Clipper Cab is very simple, and changes to the dash and controls areminimal. The TX4’s key is still used to turn the vehicle on, but the selector for the automatic transmission is gone, its place taken by a rotary selector from Zero EVwith forward, reverse and neutral positions. Also, the fuel gauge has been replaced by a battery capacity gauge. Driving on urban and suburban roads, the powertrain in its current state of tune is a little sluggish when moving off from a standing start, to the point of being a concern when joining a busy road even with the pedal to the floor. Medwell acknowledges that, and says the company plans to address it through a small change to the ECU’s software. “We have reduced the power output of the motor quite a lot, because range is a more important factor than 0-60 times,” he says. “We will tune it up a little because it is a bit slow off the line. It is quite punchy when you go from 20 to 30 mph, but 0-10 needs to be quicker.” Unlike many modern EVs, the Clipper Cab provides useful aural cues about its speed, as the powertrain whines at a pitch that rises with speed but not to the point of being intrusive. Simple conversion The simplicity of the conversion should make the process quick and therefore inexpensive. “The processwill eventually be that a taxi driver comes in, gives us their diesel cab, and 2 days later drives out with an electric version,”Medwell says. At themoment, that timescale is an aspiration, he admits, as there are delays in the supply chain. Building battery boxes and wiring looms in-house takes a couple of weeks, but once these are outsourced it will speed things up, he says. Medwell adds though that the Nissan BMS is difficult to come by if the used pack doesn’t come with one, while worldwide demand for lithium-ion cells exceeds supply. Further, the approval process through the DVSA and the VCA takes about 2 weeks. “If we could find a way to fast track that it would help us get a cab in and out in under a week.” He says the first units will be run in a pilot scheme for a number of local authorities, and Clipper Automotive is now seeking investment to fund construction of the first 10-20 cabs for the scheme. “We will be renting the cabs initially, as that will let us keep an eye on them all,” he adds. “The rental price will match the current TX4 diesel rate, so the drivers can take the savings from fuel themselves. Sales will come later.” EV’s single gear ratio. A sealed sleeve takes the power into the original taxi propshaft, which drives the standard taxi differential through a CV joint. Further, the gearbox has been turned through 90o to suit a rear-wheel- drive car, which also meant blanking off the output that originally sent drive to the Leaf’s left front wheel. One consequence of removing the differential and taking the drive from the second cog was that the Leaf’s electric motor and gearbox effectively run in reverse when the cab is moving forwards, and the original Nissan ECU limits the Leaf to 20 mph in reverse – one reason why Clipper developed its own ECU. “Basically, we can now change anything we like and go at any speed we want,” Medwell says. While some gearboxes are not designed to run for prolonged periods or at high speeds in reverse, Clipper Automotive consulted with an expert who determined that the Leaf gearbox has more than enough durability. The TX4 has a traditional and sturdy steel ladder frame chassis on which the steel body is mounted. That makes the EV conversion process quite simple, Medwell explains, as the whole body can Digest | Clipper Automotive Clipper Cab Some key suppliers HV connectors: Amphenol Cabin heaters: DBK Group ECU: JLCPCB HV cabling: Zero EV Gear selector: Zero EV Battery boxes: In house Three Clipper Cab prototypes in the workshop, the TX2 proof-of-concept vehicle on the left at the back and the two TX4s. The company plans to build an initial batch of 10-20