Executive Summary
A pure-electric Le Mans programme is feasible only if pace, energy consumption, repeated charging, thermal management and safety can be made to work together.
Electric Le Mans aims to sustain meaningful running over 24 hours, repeat the driving and charging cycle, and produce data that allows the outcome to be evaluated. LMGT3 provides an initial performance benchmark. Comparing driving cycles that include charging stops makes it possible to derive requirements for the vehicle and its energy systems.
The baseline scenario uses a ten-lap comparison cycle. An electric car averaging 3 minutes 40 seconds per lap, with a total pit visit of 4 minutes 2 seconds, completes the cycle in 40 minutes 42 seconds. The initial model's LMGT3 comparison cycle is approximately 40 minutes 50.9 seconds, giving the electric car a time margin of about 8.9 seconds per cycle. This difference sets the starting point for designing running pace and charging stops together.
An installed capacity of 300 kWh, operated from 80% to 10% state of charge (SOC), gives 210 kWh of usable energy under a proportional assumption. Ten laps require net consumption of no more than 21 kWh/lap. The simplified energy model gives approximately 21.1 kWh/lap, slightly above that budget. The first vehicle design task is therefore to reduce consumption at target pace and allocate an operating reserve.
Restoring 210 kWh during 3 minutes 30 seconds of energy transfer requires an average battery storage rate of 3.6 MW. Connection and disconnection shorten the transfer window when included in stationary time. External supply power also covers battery and charging equipment losses and auxiliary loads. Repeated charging curves and cooling performance guide the design of the vehicle and pit energy systems.
Active downforce and a fan rotor energy buffer form a development concept linking corner entry, cornering and exit. The proposed system uses regenerative power to drive the fan, produces the required tyre normal load, and returns rotational energy from the rotor to the drivetrain on exit. Fan consumption and recovered energy are calculated separately from the baseline vehicle model.
This whitepaper connects target pace, stint energy and charging requirements in one vehicle and operating model. Development proceeds from integrated time, energy and mass modelling to repeated battery, charging and thermal tests, vehicle integration and extended endurance running.
01 Purpose and Opportunity
Electric Le Mans aims to build electric racing heritage through endurance, efficiency and reliability.
Broadening the assessment of electric performance
Acceleration, power, battery capacity and range are accessible ways to describe an electric vehicle. Under repeated high loads, however, these figures alone cannot explain the capability of the complete car. The vehicle must be able to recharge after fast running, maintain useful performance as heat accumulates, and withstand repeated use of both its components and operating procedures.
Electric Le Mans extends the assessment of electric performance to repeatability and system integration. It evaluates the complete vehicle in an environment where driving efficiency, pit energy transfer, thermal management and safety affect one another.
Why Le Mans
A 24-hour race requires both pace and sustained operation. The vehicle must be ready for its next stint while drivers, tyres, traffic, temperature and weather change. Performance that appears sufficient at component level may prove inadequate once the car and its operating processes are integrated.
The value of a Le Mans challenge lies in addressing these interacting demands in a public race environment. It connects technology developed on the test bench and track with race operations, demonstrating its contribution through running records and race results.
Opportunities for manufacturers and technology partners
Established manufacturers have an opportunity to connect their racing experience with capability in electric systems. Emerging brands can develop an identity through their own technical and operating experience. Partners in batteries, charging, thermal management, controls and data can assess how their technologies perform within an integrated system.
The programme's lasting assets are its race results and the technical data that explains them. Repeated charging data, cooling design experience, fault response records and energy management models provide a foundation for further research and product development.
Brand value grows through this process. Distance covered, performance sustained and problems resolved give the challenge substance and demonstrate technical capability.
02 Objectives and Scope
Success is defined by safe completion, meaningful running, repeatable operations and reusable validation data.
What completion means
For this project, completion means more than crossing the finish line after 24 hours have elapsed. The car must cover a meaningful distance throughout the race, repeat its charging and driving cycles, and operate safely alongside other competitors.
Assessment will record total distance and completed laps, actual running time, charging and maintenance time, unplanned stops, power restrictions and major faults. Running availability is initially defined as actual running time divided by the total assessment period. Charging, maintenance and other stationary time will also be recorded separately. These records explain both how long the car ran and why it stopped.
Targets such as minimum distance and running availability will be set through the time and energy model, vehicle testing and discussions with the organisers. The project's internal technical success criteria will be managed separately from the event's official requirements for finishing and classification.
Completion objectives and performance benchmarks
A programme centred on completion still needs performance criteria. Pace affects vehicle behaviour and interactions with traffic in a multi-class environment, and helps determine the distance that can be covered in 24 hours once pit time is included.
LMGT3 provides the performance benchmark for driving and pit time. Endurance racing data makes the electric car's required pace and operating conditions explicit over the same distance.
| Category | Meaning within the project |
|---|---|
| Overall objective | Safe, meaningful completion of 24 hours, with validation data |
| Performance benchmark | Comparison of time over equal distance using LMGT3 lap and pit data |
| Design targets | Lap time, stint length, energy and charging requirements derived from the comparison model |
| Validation results | Values established through modelling or testing, together with their applicable conditions |
The comparison combines lap time and pit time. Even if faster running offsets part of a charging stop, any associated increase in energy consumption changes the charging requirement. Matching the time of a single cycle is the starting point for assessing 24-hour operations.
Entry pathway and matters for agreement
The project is considering Garage 56 as its entry pathway. Discussions with the organisers will connect the proposed vehicle and operating plan with entry conditions, translating the intended year's regulations and technical requirements into vehicle and pit design.
Matters for agreement include vehicle performance and behaviour, battery protection, high-voltage safety, pit charging equipment, rescue and recovery. Early design discussions also cover power supply, available space, concurrent work during charging, and operating conditions for active aerodynamic devices and energy buffers.
Assessing success
Success combines sustained running, safe and predictable operation, repeatability of the energy system, and traceable technical evidence. Braking behaviour and power restrictions must remain manageable as battery conditions change. Pit personnel must understand the vehicle's state and who has authority to carry out or stop an operation.
Technical results are recorded through driving and charging logs, measurement conditions, calculation methods, and fault and maintenance histories. Each technology's performance is linked to its operating conditions and data for use in subsequent design and research.
Baseline concept and analytical scope
The baseline concept is a battery-electric prototype charged from an external electricity supply. Battery swapping and an onboard combustion generator for propulsion are excluded from the baseline scenario. Other energy sources or swapping arrangements, if investigated, will be assessed as separate alternatives.
The analysis treats the vehicle, battery, charging installation, pit operations and strategy as one system. Fan-based active downforce and rotational energy buffering are evaluated separately, without assigning an assumed performance benefit to the baseline model. Detailed design, committed budgets and schedules, and production business cases belong to later stages.
Within this scope, the next question is how much time and energy a driving cycle requires. Requirements are calculated first, followed by vehicle architecture and operations, then the validation work and collaboration needed to investigate them.
03 Race Time and Energy Budget
Target pace and stint length must be set by combining driving time with pit time, then translating the result into energy and charging requirements.
Comparing a complete cycle
A stint is a continuous period of running. The initial calculation defines one comparison cycle as ten laps followed by one pit visit. Pit visit time is the sum of pit-lane transit and stationary time. The measurement intervals for driving laps and the pit visit must not overlap.
The following table defines the initial time comparison model. The EV column sets out design targets and operating assumptions; the LMGT3 column provides comparison inputs for deriving the required performance. Appendix A records the benchmark data requirements and aggregation method.
| Ten-lap cycle | LMGT3 reference | EV target scenario |
|---|---|---|
| Lap time | Approx. 3 min 57.34 s | 3 min 40.00 s |
| Driving time over ten laps | 39 min 33.38 s | 36 min 40.00 s |
| Total pit visit | 1 min 17.55 s | 4 min 02.00 s |
| Assumed pit-lane transit | 32.00 s | 32.00 s |
| Stationary time | 45.55 s | 3 min 30.00 s |
| Complete cycle | 40 min 50.93 s | 40 min 42.00 s |
With the EV pit visit fixed at 242 seconds, the lap time that matches the reference cycle is:
This is approximately 3 minutes 40.89 seconds. The target lap time of 3 minutes 40 seconds provides 8.93 seconds of time margin per cycle. Additional pit work, traffic, increased consumption and reduced charging power use this margin and are included in the cycle calculation.
From installed capacity to an energy budget
Assume an installed capacity of 300 kWh, departure at 80% SOC and return at 10% SOC. SOC describes the battery's state of charge. The initial calculation converts the SOC difference directly into a proportion of installed energy:
In this baseline model, energy scales proportionally with SOC, giving an average net consumption budget of 21 kWh/lap over ten laps. Appendix A sets out the method for adjusting usable energy to battery conditions.
Energy available for driving is the 210 kWh window less pit entry and exit, waiting and operating reserves. The 10% lower SOC limit remains the boundary of the operating window. These allocations reduce the normal lap budget below 21 kWh/lap.
Energy consumption per lap
The baseline energy model assumes a vehicle mass of 2,000 kg, CdA of 0.70 m², drive efficiency of 93%, friction coefficient of 1.5, ClA of 2.5 m², rolling resistance coefficient of 0.015, and auxiliary power of 5 kW. CdA is the product of drag coefficient and reference area. ClA here denotes the magnitude of the downforce coefficient multiplied by reference area.
| Energy term | Example calculation | kWh/lap |
|---|---|---|
| Aerodynamic drag | 8.07 ÷ 0.93 | 8.68 |
| Rolling resistance | 1.55 ÷ 0.93 | 1.67 |
| Acceleration energy | 18.12 ÷ 0.93 | 19.48 |
| Cooling and auxiliaries | 5 × 220 ÷ 3,600 | 0.31 |
| Regenerative recovery | −18.12 × 0.50 | −9.06 |
| Total | Sum before rounding individual terms | Approx. 21.07 |
Calculated consumption is approximately 21.1 kWh/lap, exceeding the 21.0 kWh/lap budget by about 0.1 kWh/lap. Individual terms are displayed to two decimal places; the total is calculated before rounding.
The table is an initial energy balance combining drag, rolling resistance, acceleration, auxiliaries and recovery. Appendix A sets out the speed-profile-based lap calculation and the records associated with each input.
The model calculates battery-side recovery as 50% of the 18.12 kWh mechanical energy term. Time-resolved recovery depends on braking speed, drivetrain and battery conditions, and tyre limits.
Charging requirements and model boundaries
Restoring the cycle's energy budget of 210 kWh in 210 seconds requires an average storage rate of 3.6 MW. Replenishment at each stop is set by the preceding stint's consumption and the target departure SOC.
This calculation uses 210 seconds of actual energy transfer. Including connection, checks, shutdown and disconnection within a 210-second stop shortens the transfer window and raises the required power. Chapter 05 develops this time allocation into charging system requirements.
Time and energy are calculated for the same vehicle following the same speed profile. The driving, battery and pit models jointly determine lap time, stint consumption and charging duration.
04 Vehicle and Energy Systems
Mass, battery architecture, aerodynamics, drivetrain and braking must be developed together to meet the lap-time and energy targets simultaneously.
Mass budget and battery architecture
Increasing battery capacity may extend a stint, but also increases mass and packaging demands. Cooling, crash protection and high-voltage components must be included. The vehicle mass budget must cover the body and structure, battery, drivetrain, cooling, suspension and brakes, electrical equipment, and loads carried in the specified operating condition, using consistent accounting boundaries.
The design calculation 300 kWh ÷ 0.50 kWh/kg gives 600 kg. Using cell specific energy gives cell mass, to which the enclosure, wiring, cooling and protective structures are added. Using pack specific energy gives the mass included in that pack configuration. Appendix A records the specific-energy basis and mass scope.
The model uses 500 Wh/kg as its specific-energy design assumption. Battery development addresses specific energy, charge acceptance, cycle life and safety within the same cell and pack configuration.
Vehicle mass is the sum of the chassis, battery, drivetrain, cooling, reinforcement and loads carried in the defined operating condition. When using an existing LMH chassis, removed components and added electric components are recorded in the same mass budget. That budget connects the vehicle architecture to the energy model's 2,000 kg assumption.
Integrating aerodynamics and tyres
Aerodynamic development must address both the grip required for target pace and the energy consumed on the straights. Downforce, drag, cooling flow, ride-height variation and stability in traffic should be assessed together. Rolling resistance also requires correction for aerodynamic normal loads and operating conditions.
Active downforce adds tyre normal load where it is needed. The grip model uses tyre load sensitivity, temperature and surface conditions to calculate the resulting grip and cornering performance.
Active downforce controls tyre normal load. Vehicle mass and inertia remain in the acceleration, braking energy and structural-load calculations. Fan-system design combines cornering performance with fan power, added mass, airflow and tyre loading.
Drivetrain and regenerative braking
Motors and reduction ratios should be selected for efficiency and thermal loading across the actual speed and torque range, alongside peak power. Driven-axle layout and regenerative braking distribution must also account for vehicle behaviour, packaging and mass.
Regeneration operates within battery charge acceptance, motor and inverter limits, and tyre grip. Recovery may fall at high SOC or when thermal limits are reached. Friction brakes must still provide the required deceleration and stability. The transition between regenerative and friction braking must be designed and validated to remain predictable to the driver.
The value of regeneration depends on its relationship with running time. Recovering more energy may worsen the complete cycle if it lengthens braking zones or destabilises the car. Energy targets and braking strategy must be adjusted within the same lap model.
The fan rotor energy buffer concept
The proposed fan rotor energy buffer routes part of the regenerative power above battery charge acceptance to the fan on corner entry, maintains the required downforce through the corner, and electrically recovers rotational energy from the rotor on exit.
Fan input power is divided between energy stored by accelerating the rotor, work on the airflow and losses. Recoverable energy is determined by rotor inertia, the permitted speed change, aerodynamic and mechanical losses, and generation and power-conversion efficiency.
Here, is the moment of inertia in kg·m² and is angular velocity in rad/s. The expression gives the change in mechanical rotor energy in joules; dividing by 3,600,000 converts it to kWh. Electrical recovery must account for aerodynamic and mechanical losses during deceleration and losses in conversion. Reducing rotor speed may also change downforce, so the grip required on corner exit constrains the recoverable amount.
Regenerative power available to the fan is bounded by battery charge acceptance and the limits of the motor, inverter, tyres and DC link. The DC link is the direct-current power connection between conversion devices. When regenerative power is insufficient, the battery supplies the fan or its operating state is adjusted.
Chapter 03's baseline calculation excludes additional fan consumption and recovery. The fan concept's energy balance allocates braking energy between battery recovery and fan supply. Chapter 07 sets out the comparison of the baseline vehicle, fan operation, and combined fan operation and energy recovery.
05 Safe Charging and Thermal Management
Charging performance is the ability to transfer the required energy safely within the available time and repeat the process through subsequent driving cycles.
Stationary time and actual charging time
A pit visit is divided into transit and stationary time. Stationary time must then distinguish connection, state checks, energy transfer, shutdown and disconnection. Whether operations can overlap depends on equipment, procedure design and the applicable conditions.
The baseline stationary-time budget is 210 seconds. In a scenario allocating 30 seconds to connection, checks, shutdown and disconnection, 180 seconds remain for energy transfer. Storing 210 kWh in that window requires an average storage rate of 4.2 MW.
Stationary time consists of operating tasks and energy transfer. Power ramp-up, ramp-down and temperature restrictions are included in the charging curve; the total energy stored over the transfer window determines the required stop duration.
Power measurement boundaries and supply infrastructure
Energy stored in the battery, electrical energy entering its terminals, charger output and supply-side input must be distinguished. Internal heating, conversion and transmission losses, pumps and cooling loads must be accounted for at the appropriate boundaries.
Supply power is calculated by adding internal battery losses, charging and transmission losses, and auxiliary demand to the 3.6 MW average storage rate. Cell voltage and current, charge acceptance across SOC, and system efficiency determine charger and supply requirements.
Charging infrastructure must be developed with the vehicle. Supply capacity, peak power, cables, connectors, cooling, controls and emergency shutdown all need definition. Local energy storage could supplement instantaneous supply power, but replenishing that store and meeting the total energy demand must also be included.
Thermal management over repeated cycles
Thermal development measures temperature rise, thermal equilibrium and headroom at the next departure across repeated driving and charging cycles. These results determine cooling capacity and charging and power controls.
Monitoring must cover cell-to-cell variation and local peaks, tabs, busbars, connectors, motors and inverters as well as average battery temperature. Cooling options should be compared on heat rejection, mass, pumping power, leakage, serviceability and insulation requirements. Cooling with airflow while driving and cooling while stationary need separate assessment.
The baseline model allocates 5 kW to cooling, pumps and other auxiliaries. Active downforce fan power is a separate energy term. Changes to the cooling configuration update mass, drag and power consumption alongside thermal headroom.
Safety states and operating authority
High-voltage safety requires control of the vehicle during normal running, charging, servicing, faults and incidents. Vehicle and charger status indications, permission to transfer energy, emergency shutdown and release authorisation must be consistent. Responses to sensor and communication failures must be defined alongside normal operation.
Safety design defines connection locking, permission to transfer energy, fault shutdown, electrical-state checks after shutdown and release conditions. Work authorisation is tied to equipment protection states and electrical safety assessment; the software display communicates those states to personnel.
Battery fault and incident response connects driver rescue, protection of nearby personnel, vehicle recovery and isolation. Defined roles and stop authority are exercised in training that includes night operation, rain and failed connections. Detailed procedures are maintained in the trackside operating documentation.
06 Race Operations over 24 Hours
Operations over 24 hours adjust pace, stints and charging to heat accumulation, degradation, traffic, weather and faults.
The baseline scenario and time accounting
The first operating model should assume normal running without relying on favourable neutralisation periods. Driving, pit visits and maintenance must be accounted for without overlap, linking the energy consumed and replenished in each cycle.
The battery starts the race charged, while the final stint may not require a subsequent recharge. Dividing 24 hours by a single cycle time therefore does not give an exact lap count or number of stops. Initial and final conditions, remaining energy, treatment of the final lap and actual race conditions must be included.
The model should produce running time, pit time, energy charged, peak temperatures, power restrictions, and fault and recovery time alongside total distance. Results should be compared across changing conditions rather than reduced to one favourable outcome.
Changing conditions and degradation
Traffic changes average lap time and acceleration and braking patterns, and may affect cooling. Rain and temperature changes affect grip, target pace and energy consumption together. Where possible, they should be represented as operating conditions that evolve over time rather than as independent corrections added to a result.
Each cycle updates temperature, usable energy and charge acceptance. Charging curves and power-limit data from repeated testing are applied to the cycle's state, together with tyre and friction-brake loads when regeneration is restricted.
If charging fails or available power falls, the operating model compares shorter stints, reduced pace and additional stops. The next driving and charging plan is adjusted within safe operating limits.
Neutralisations and pit decisions
Safety Car, Full Course Yellow and Slow Zone are modelled as separate scenarios with their applicable track sections, pit access, vehicle positions and restart conditions. The intended year's rules are applied to each time and energy calculation.
The hypothesis that neutralisation can reduce the relative cost of charging should be evaluated by scenario. Waiting at low SOC for a favourable intervention cannot replace the baseline plan. Minimum return-to-pit energy and thermal limits must be maintained.
The amount charged should reflect the next stint's demand, temperature, the actual charging curve and the timing of the return to the track. Safety and permitted working arrangements must be established before combining charging with driver changes or tyre work.
Data and human decisions
The operating system should use SOC, usable energy, temperature, charge acceptance, traffic and weather to present options for the next stint and stop. Required functions include remaining-stint forecasts, charging-time forecasts, thermal warnings, scenario comparisons and event records.
Forecasts show their input conditions and expected range. Missing data or model error beyond defined thresholds triggers a return to predefined operating rules. AI can support forecasting and scenario comparison.
Accountable operating personnel retain strategic authority. Protective functions should not depend on an experimental strategy model. Charging events, power restrictions, driver feedback and fault responses should be recorded on a common timeline to support subsequent decisions and post-race analysis.
07 Feasibility Limits and Validation
Development tests connect lap energy, repeated charging, thermal management and vehicle behaviour to system requirements.
What the current calculation establishes
The example exposes tight time and energy constraints. The target EV cycle is approximately 8.9 seconds shorter than the comparison cycle, but calculated energy consumption already slightly exceeds the budget. Pit work, charging losses and operating reserves make the requirements more demanding.
Design adjusts target pace, stint length, capacity, mass, aerodynamics and charging capability together. More capacity changes vehicle mass, driving consumption and replenishment energy alongside stint length. The integrated model calculates these relationships.
Development tasks and test outputs
| Development area | System impact | Tests and deliverables |
|---|---|---|
| Pace and lap energy achieved together | Excess driving time or charging demand | Lap and energy models using the same speed profile, calibrated against measurements |
| Pack specific energy and vehicle mass | Changed acceleration, braking, tyre and energy demands | Pack architecture, complete vehicle mass budget and component measurements |
| Repeated high-power charge acceptance | Longer stops and restricted power at departure | Charging curves across SOC and temperature, with repeated cycle tests |
| Heat rejection and temperature spread | Accumulating thermal restrictions or departure from safe limits | Thermal equilibrium and transient tests with local measurements |
| Braking with limited regeneration | Higher consumption and altered vehicle behaviour | Braking tests at high SOC, high temperature and low grip |
| Net benefit of the fan concept | Consumption and mass offset performance gains | Fan maps, rotor inertia, recovery measurements and vehicle dynamics comparisons |
| Pit procedures and fault responses | Longer stops or inability to release safely | Repeated timing measurements and failure drills |
| Entry and infrastructure conditions | Changes to architecture or operating plans | Applicable regulations and technical discussions with the organisers |
Each development task is linked to input data, the responsible discipline, acceptance criteria and deliverables. Criteria follow from the test purpose and system requirements.
Fan comparison tests use the same driving conditions for the baseline vehicle, fan operation, and combined fan operation and energy recovery. Lap time, consumed and recovered energy, tyre loading and added mass establish each configuration's contribution.
Test deliverables comprise input data and calculation records, component performance curves, repeated-cycle logs and operating conditions. Entry preparation connects the intended year's regulations and the organisers' technical discussions to design requirements.
Validation stages
The first stage is model validation. Establish the benchmark data sources and timing intervals, then connect lap-time, energy, mass and charging models. Distinguish assumed inputs from measurements and calculate the range over which requirements remain achievable under adverse conditions.
The second stage covers cell, module and charging tests. Measure charge acceptance, heat generation, usable energy and changes over repeated cycles across the expected SOC and temperature range. Establish the effects of cooling and interconnections when extending cell results to pack level.
The third stage is integrated system testing. Operate the battery, charger, cooling and protective functions together under normal cycles and communication, connection and power faults. Confirm that component-level performance survives integration.
The fourth stage is vehicle testing. Measure pace and consumption during the same runs, including behaviour under regenerative limits and changing tyre conditions. Use differences between model and measurement to update charging plans, mass assumptions and aerodynamic design.
The final stage is extended endurance operation. Evaluate the car and its personnel together through night running, changing weather, crew handovers, repeated charging and fault response. These results, together with the organisers' requirements, inform the assessment of entry readiness.
Criteria for progression and redesign
Progression requires the preceding stage's results to satisfy system requirements. Lap consumption must fit within the budget after energy reserves are allocated. Charging must fit within the pit budget after actual work and losses are included. Thermal and electrical safety limits must be established from the selected components and validation results.
When a requirement is missed, the cause is classified as model error, a component limit or an incompatible combination of targets. The response is further testing, a configuration change or an adjusted target.
The development priorities are energy consumption at target mass and pace, and repeated replenishment in time for the next stint. The following chapter defines the work and collaboration needed to deliver them.
08 Development Path and Collaboration
Development proceeds through modelling, components, system integration, vehicle development and entry preparation, with collaboration organised around each stage's expertise and deliverables.
The first development task
The baseline scenario must first be consolidated into one consistent input set. Benchmark data, speed profiles, mass boundaries, SOC and energy definitions, and charging procedures need to be connected. Manage the input set around this whitepaper's baseline values, recording the applicable conditions and reasons for changes when using values from earlier editions or alternative scenarios.
The first deliverables are a reproducible lap and stint model, an assumptions and sources register, sensitivity results and priority tests. Battery and charging partners define the test scope; model and test results guide vehicle packaging and component specifications.
Deliverables by stage
| Stage | Deliverables | Basis for progression |
|---|---|---|
| Baseline model | Consistent time, energy and mass models, with an assumptions register | Clear target combinations and validation priorities |
| Key component tests | Charging, thermal and regeneration data | Demonstrated performance and repeatability within stated conditions |
| System integration | Combined battery, charger, cooling and protection results | Required behaviour maintained under normal and fault conditions |
| Vehicle validation | Pace, consumption, braking, tyre and pit-operation data | Model-to-test differences understood and managed at vehicle level |
| Entry preparation | Endurance results and technical and safety submissions | Organiser requirements and internal readiness criteria satisfied |
The development schedule is built from each stage's test scale, personnel and facilities, and equipment lead times. Deliverables and progression criteria are linked to that schedule.
Required collaboration
Vehicle development requires the integration of aerodynamics, dynamics, structures, tyres and braking. Battery work requires cell characterisation, pack design, repeated charging and degradation tests. Charging and thermal teams must jointly define power and heat flows across the vehicle and trackside installation.
Operations and safety specialists must connect high-voltage states, pit procedures, incident response and entry requirements. Data specialists support measurement reliability, model calibration, operating decisions and analysis. Each collaboration should be defined by the question to be answered and the evidence to be produced, as well as by the technology supplied.
The fan rotor concept is a research task linking aerodynamics, rotating machinery, power conversion and vehicle control. It proceeds alongside baseline vehicle development, with fan consumption, recovery and vehicle behaviour covered by a separate model and comparison tests.
Using data and results
Data access, disclosure, intellectual property and publication principles should be agreed early. Public summaries and internal design information should be distinguished, while externally reported performance remains traceable to measurement conditions and evidence.
Charging, cooling, braking and operating experience will support further research and the development of high-performance vehicles and components. The resulting data and market needs guide product development priorities.
The next step
Electric Le Mans proposes to demonstrate electric endurance performance publicly and turn the experience into technical knowledge and brand credibility. Achieving that objective requires completion to be translated into time, energy, mass, thermal and safety requirements, then into questions that can be tested.
The next step is an integrated time, energy and mass model, followed by repeated charging and thermal tests linked to vehicle design. This work defines the vehicle architecture and partnerships, leading into vehicle integration, extended endurance running and entry preparation.
Appendix A Baseline Scenario and Calculation Methods
Inputs and their status
| Parameter | Value | Status and scope |
|---|---|---|
| Lap length | 13.626 km | Baseline lap length |
| Comparison distance | 10 laps, 136.26 km | Baseline comparison cycle |
| EV lap time | 220 s | Design target scenario |
| EV pit-lane transit | 32 s | Time comparison assumption |
| EV stationary time | 210 s | Stop budget including operating tasks and energy transfer |
| Reference driving time | 2,373.38 s over 10 laps | Initial comparison input |
| Reference pit visit | 77.55 s | Initial comparison input |
| Installed energy | 300 kWh | Initial design assumption |
| SOC window | 80% → 10% | Operating assumption; energy conversion to be calibrated by testing |
| Usable energy | 210 kWh | Proportional SOC calculation, before allocating additional reserves |
| Vehicle mass | 2,000 kg | Energy-model assumption; must be linked to the complete mass budget |
| Specific energy | 500 Wh/kg | Design assumption; accounting basis tracked in the model definitions below |
| CdA / ClA | 0.70 / 2.5 m² | Baseline aerodynamic model inputs |
| Drive efficiency | 93% | Constant-efficiency assumption; replace with speed and torque maps |
| Friction / rolling resistance coefficient | 1.5 / 0.015 | Baseline tyre model coefficients |
| Regenerative recovery | 50% of 18.12 kWh | Battery-side recovery from the mechanical energy term |
| Auxiliary power | 5 kW | Baseline auxiliaries, excluding the active downforce fan |
| Active fan consumption and recovery | Excluded from baseline | To be included in the separate concept assessment |
Model definitions and calculation records
- Time comparison: Initial inputs are 2,373.38 seconds of driving over ten laps and a 77.55-second pit visit. The displayed lap time is rounded; multiplying it by ten differs from the driving aggregate by 0.02 seconds. Calculations use the aggregate's precision. This is a single-cycle time model; 24-hour results incorporate the starting and finishing conditions and cycle-by-cycle changes in Chapter 06.
- Benchmark records: Current inputs define the baseline scenario. Linking the underlying session, lap and pit records with their aggregation method is a task in establishing the dataset. Until that record is attached, the inputs are classified as scenario values rather than measurements of a particular continuous stint or official class averages.
- SOC and energy: The baseline calculation scales installed energy proportionally with SOC. The battery model uses energy measurements to adjust usable energy for voltage, temperature, degradation and power restrictions.
- Drive efficiency: The 93% input is a constant efficiency applied to drag, rolling resistance and acceleration terms. Whether it includes internal battery losses remains a model-definition decision. The integrated model assigns each loss to its accounting stage and includes the difference between terminal and stored energy once when connecting consumption to the SOC budget.
- Specific energy: The cell or pack basis of 500 Wh/kg is a decision for battery configuration selection. A cell basis adds pack hardware mass separately; a pack basis records the components and mass included.
Basic time and energy equations
The initial equations use seconds for time, kWh for energy and kW for power. Energy is an amount consumed or stored; power is the rate of energy transfer. One MW equals 1,000 kW. Specific energy, in Wh/kg, is stored energy per unit mass.
is the number of laps, is lap time, is pit-lane transit time and is stationary time.
Reserves and other consumption are allocations within usable energy. They must not be counted again as energy remaining below the lower SOC limit. Other consumption includes pit movement and waiting that are not already represented in the lap model.
is the energy to be restored and is actual energy transfer time.
Transfer time differs from total stationary time. When replacing the constant-power calculation with a charging curve, integrate the rate of energy storage over the available window. If terminal power is used instead, account for internal battery losses.
The lap model calculates vehicle motion and energy using the same speed, gradient and aerodynamic conditions. It calculates instantaneous wheel power, applies efficiencies and power limits separately to positive drive power and recoverable braking power, then adds auxiliary consumption. It uses the same energy accounting basis as the component balance, counting drag consumption and regenerative recovery once each. Records for the initial 8.07, 1.55 and 18.12 kWh inputs include the source speed profile, integration intervals and calculations.
Required benchmark data records
Lap and pit data should identify the race year, session, vehicle, sample size, selected intervals and exclusion criteria. State whether the comparison uses medians, means or an actual continuous stint, and check for overlap between in-laps, out-laps and pit intervals.
Selecting only fast laps or mixing neutralised and normal running can change the target. Where lap and pit statistics from different cars or periods are combined, label the result as a constructed comparison scenario, distinct from an observed stint.
Appendix B Sources and References
Project material
This whitepaper is the project's central account of its purpose, system architecture, baseline assumptions, calculations and development plan. Presentation materials summarise the arguments and calculations developed here.
The eight chapters consolidate the project's earlier 16-part whitepaper. Appendix A maintains the baseline inputs and calculation methods.
External references
- ACO, Garage 56 the spirit of Le Mans, 20 May 2016. Historical purpose of Garage 56 and background to safety and performance discussions.
- Woodford, Ransil and Chiang, Advanced Batteries Beyond Li-ion, 2012. Cell and pack mass and energy metrics.
- NASA NTRS, Study of flywheel energy storage for space stations, 1984. Rotational energy storage and electrical recovery principles.
External references checked: 3 November 2026.