Thanks to the use of the new B series of Molicel cells (INR-18650-P30B), opposed to A series (INR-18650-P26A), the new McMurtry Spéirling PURE validation prototype (VP1) has a charge time of under 20mins (this includes cooling the cells back down).
McMurtry Automotive says this capability ‘truly unlocks usable electric performance on track days’ and is attributable to: a 23% reduction in DCIR (direct current internal resistance); the fast charge rate raised from 2C to 3C (full SOC — state of charge); and a continuous discharge current of up to 36A.
Thomas Yates, McMurtry Automotive’s managing director, said: “Molicel’s products offer a virtuous circle of lightweighting within our vehicle. Using Molicel’s B series technology significantly contributes to making a lightweight, compact, fast-charging driver’s car with some of the most accessible performance characteristics in the world.”
McMurtry, using Molicel technology, already holds the outright record at the Goodwood Festival of Speed with its innovative electric fan car. McMurtry has now unveiled an improved version of that vehicle, which is available for sale. It is designed for high-performance track use, and the validation prototype (VP1) of the Spéirling PURE was first shown at the Goodwood Festival of Speed 2023.
The improvements achieved include: the top speed being raised from 150 to 190mph; cornering G-force raised by 25%; run time extended to 10 laps of ‘Silverstone National’ at lap-record pace; and a fast charge in 20mins —performance figures resulting from ‘improvements in the battery from both Molicel’s high power cells and McMurtry’s proprietary pack design’.
As part of the 2024 testing programme, the VP1 prototype will be used to attempt racetrack records and to demonstrate multi-lap usable performance beyond the hillclimb discipline that launched McMurtry Automotive to fame at
Goodwood. It is also worth noting that customers’ cars will benefit from using cells that are ‘two generations beyond’ those in VP1 — the P50B cells are not yet available on the market.
This cell is a 5.0Ah 21700 form factor lithium ion cell that offers a charge rate that is some 1.6-times greater than the P30B at cell level. Moreover, Molicel says its performance and more favourable packing efficiency can also help deliver 17% improvements in ‘gravimetric and volumetric energy density’ over what is in the existing prototype.