BESS-backed EV charging hub
125 kW / 250 kWh BESS + 2 × 60 kW DC chargers
Two 60 kW DC chargers (four 30 kW CCS-2 outputs) on a protected AC bus, with a 125 kW / 250 kWh BESS on the same bus. With the grid present, chargers run directly from the grid and the PCS charges the battery from spare capacity. On grid failure, a coordinated isolation panel opens and the battery forms the AC bus so all four outputs keep charging.
How the energy moves.
Conceptual single-line diagram · 2 × 60 kW EV chargers | 4 × 30 kW outputs | 125 kW PCS | 250 kWh battery
Scroll the diagram sideways →
Single lines represent power circuits, not individual conductors. AC links L1 + L2 + L3 + N; PE to all equipment. Protective-device ratings, cable sizes, neutral switching, earthing and transfer sequencing are final-design items. Backup is ~2 h subject to usable energy, conversion losses and charging demand.
Grid available
- Grid → AC bus → both EV chargers, without passing through the battery.
- Grid → AC bus → PCS → battery charging.
- EMS limits battery charging to spare incoming grid capacity.
Grid unavailable
- Grid isolation opens; utility backfeed is blocked.
- Battery → PCS → AC bus → both chargers / four cars.
- Combined AC demand is held within the 125 kW PCS rating.
Technical specification.
Charging
- EV chargers2 × 60 kW DC
- Outputs4 × 30 kW CCS-2 (two guns per charger)
- Aggregate DC output120 kW
- AC design basis400 V 3-phase / 230 V P-N · 50 Hz
Battery energy storage
- Rated power / energy125 kW / 250 kWh
- PCS125 kW bidirectional · 181 A nominal AC
- Battery window680–900 V DC (abs. max 950 V) · 200 A max
- PCS moduleIP20 · forced air · -30 °C → +60 °C (derates > 45 °C)
- Indicative backup250 kWh / 120 kW ≈ 2.08 h ideal
Grid interface & protection
- Main incomerEnergy meter + breaker · surge / earth protection
- Grid isolation / transferCoordinated PCC panel · no backfeed off-grid
- Branch protectionBreakers per charger and PCS feeder
- DC sideBMS · DC fuse / isolator · contactors & pre-charge
- ControlTOBOR EMS charge / discharge limits
Design-basis values from a TOBOR project offer. *Cycle life depends on cell OEM specification, depth of discharge, temperature, C-rate and end-of-life criterion. Final ratings, certifications and performance guarantees follow the approved project-specific design.
- Public charging hubs and highway stops with unreliable supply
- Fleet depots that cannot afford charging downtime
- Malls, hotels and offices adding fast charging with backup
- CPOs needing guaranteed uptime per charging point
Want this design at your site?
Tell us your vehicles, loads and grid connection. Our engineers adapt the design and send a single-line diagram with the offer.
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