EV Infrastructure
Charging Calculators & Site Planning
A 350 kW charger almost never gives you 350 kW for long. Pick a vehicle (car, Class 8 semi or air taxi), pick a plug, and watch where the power actually goes — then put a dozen of them on one electrical service and see what the site really needs.
1 · Vehicle
2 · Charger
3 · Session
Compare
Pin up to 3 vehicle + charger combos to overlay their curves. Classes mix freely, so try a Model 3 against a Tesla Semi.
Power delivered vs. time
Data table (per-minute samples)
State of charge vs. time
Minutes per 10% slice
| Slice | Min | Avg kW |
|---|
Pinned combos
| Combo | Time | Avg kW | Peak kW | kWh | Range | Limit |
|---|
How we calculate this: vehicle session
Delivered power at every 1-second step is min(car curve at this SOC after temperature, charger rating, charging voltage × cabinet amps, 800V fallback ceiling, station output limit). The lowest of those is what the chart shows; whichever wins most of the session names the "main limit".
The 500 A rule. A cabinet has a current ceiling as well as a power rating. Most 350 kW CCS cabinets stop at 500 A, and power is volts × amps, so a 400 V-class pack sitting at 345–390 V is physically capped near 173–195 kW. Pack voltage is modelled as a straight line from vMin at 0% SOC to vMax at 100%.
Losses. Energy into the pack is integrated from the delivered power; energy billed at the plug is that divided by 0.94 on DC (0.92 on AC), so the meter always reads more than the pack gained.
All numbers are estimates. Real sessions also carry HVAC and control loads, SOC calibration windows and cabinet sharing, none of which are modelled here.
Station battery
Discharge
Grid & queue
Fleet mix
The queue repeats until the battery hits its reserve floor.
Station SOC vs. time
One session under the station's output limit
Per-session log
| # | Vehicle | From | To | kWh | Time | kW |
|---|
Full charges by battery size
| Size | Usable | Full charges | Then |
|---|
How we calculate this: buffered station
Usable energy. size × stack × depth of discharge. The session pool is the slice between the starting SOC and the reserve floor, so a 250 kWh cabinet at 90% DoD, 100% → 10%, offers 250 × 0.9 × 0.9 = 202.5 kWh of stored energy.
Energy per vehicle. The Section 1 session is integrated with one extra ceiling: the station's output limit (cabinet limit × stack, plus the grid service if grid assist is on). Pack energy is then divided by 0.94 for vehicle-side losses to get energy at the cabinet, and again by the discharge efficiency to get energy pulled from the cells. Both limits are applied to delivered power, the same way the charger's own rating is.
Counting charges. Identical back-to-back sessions are subtracted from the pool until the next one will not fit; the remainder is replayed against the session's own energy curve to find how far the last vehicle actually gets. With a gap and grid assist, the battery recovers between vehicles, which is the sawtooth in the chart.
Output limit. If the cabinet limit sits below the car's curve, the session simply takes longer, and the "main limit" reads station output limit and the session chart flattens at that ceiling.
Estimates only. Auxiliary loads (HVAC, controls, thermal management), cell balancing, SOC calibration windows and utility demand limits are not modelled.
Station battery
This tab's own battery. Nothing here touches the other tabs.
Session for throughput
Sessions per day needs to know what a session costs, so this tab picks its own vehicle.
Grid service
Conversion
Recharge window
Station SOC vs. time on the grid
What a service upgrade buys
| Breaker | Cont. A | kW | Time to full |
|---|
Daily throughput
How we calculate this: grid recharge
Three-phase power. P(kW) = √3 × V × I × PF / 1000. The √3 (about 1.732) is there because the three phases peak 120° apart, so the line-to-line voltage is √3 times the phase voltage. Sanity check: 480 V × 100 A × 0.98 × √3 ≈ 81.5 kW. Single-phase drops the √3: P = V × I × PF / 1000. Apparent power, kVA, is the same sum without the power factor.
The 80% rule. A continuous load may only use 80% of a breaker's rating, so a 100 A breaker is good for 80 A continuous. Charging is a continuous load. Switch the toggle off if the number you have is already the continuous draw.
Into the battery. min(grid kW × charge efficiency, battery max charge rate), tapering above 90% SOC down to 30% of that rate at 100%, the same constant-current-then-constant-voltage behaviour the vehicles show, for the same reason. Integrated in 1-second steps.
Daily throughput takes 24 hours of grid energy at the continuous draw, carries it through the charge and discharge efficiencies and the vehicle-side losses, and divides by the pack energy one session needs. The battery does not add energy over a day: it buys burst power. The grid service sets the ceiling.
Estimates only. Utility demand charges, transformer limits, voltage drop on long runs and station auxiliary loads are not modelled.
Battery on board
Charging station
Mission
What this trailer is hauled out to do, for the charges-per-trip and kWh-per-ton figures.
Add-ons
Units
Weight breakdown
| Component | Weight | Share | Basis |
|---|
Deck layout, top down
Mission check
Every battery × every station
How we estimate this: trailer weight
Site
Anything still plugged in when the window closes is reported as departed at its achieved SOC.
Stations
Quick add creates ordinary stations. Every one of them is editable afterwards.
Selected station
Configuration changed since the last run.
Site power vs. time
Data table (site power over time)
Stations
Selected station
State of charge
Data table (selected station)
How we calculate this: site power sharing
Why fast charging slows down
As the anode fills up, lithium ions have fewer places to slot into. Push current too hard at a high state of charge and metallic lithium plates onto the anode instead, which means permanent capacity loss and a dendrite/short risk. The BMS taper above roughly 60–80% is the insurance policy.
Fast charging dumps waste heat into the cells faster than the coolant loop can pull it out. A cold pack can't accept high current either (ion mobility collapses), which is why preconditioning on the way to a charger matters so much. Too hot or too cold, the BMS cuts power to protect the cells.
Power = volts × amps, and a cabinet has a ceiling on each. Most 350 kW CCS cabinets top out near 500 A, so a 400 V-class car physically cannot exceed about 175–200 kW no matter what the sticker says; an 800 V car draws the same power at half the current and gets the full rating. Tesla went the other way, roughly 700 A but only 500 V, so a 400 V Tesla really does see 250 kW at a Supercharger, while an 800 V car plugged into one has to split its pack and settle for a fraction of its peak.
A charger's kW only means something relative to the pack it is filling. 250 kW into a 75 kWh Model 3 is 3.3C, which is ferocious. A 1.2 MW megawatt cabinet into a Tesla Semi's 850 kWh is 1.4C, which is why a megawatt still needs half an hour. Air taxis sit at the other extreme: tiny packs charged at 2–3C, several times a day, and replaced on flight hours rather than range loss.
Each of these gets a longer treatment in the articles.