BESS Sizing for EV Charging | Battery Power & Energy Requirements
A practical framework for evaluating BESS power, energy capacity and operating strategy alongside EV charging demand.
BESS sizing for EV charging should begin with the difference between the site charging profile and the grid capacity that can be made available. Power and energy are separate design variables: the required BESS power depends on the peak support requirement, while energy capacity depends on the duration and operating strategy.
Define the BESS sizing problem
Peak Power Gap
Estimate the charging demand that must be supported above the permitted grid import or site operating limit.
Support Duration
Determine how long the BESS must provide the required power during the relevant charging window.
Daily Energy Profile
Map charging energy, grid import, solar generation and BESS operating windows over a representative day.
Operating Strategy
Define peak shaving, load shifting, renewable utilisation, backup or combined objectives before final sizing.
Questions before final BESS selection
What determines BESS power?
The peak power difference that the storage system must support or manage during the target operating condition.
What determines BESS energy?
The magnitude and duration of the required support, together with usable energy, operating limits and the selected control strategy.
How does solar change the model?
Solar generation can alter the site net-load profile and create opportunities for coordinated charging and storage operation.
What about future chargers?
Future charging points should be included in the site model where expansion is expected, otherwise the initial BESS architecture may be undersized.
Relevant ABG BESS + EV Charging Solutions
Smart Integrated BESS + EVSE Station
Integrated BESS and EV charging architecture for configured site requirements.
Ultra-High Power DC Charging System
High-throughput charging platform for sites requiring detailed power planning.
BESS sizing inputs for an RFQ
- Sanctioned load and grid limit
- Transformer rating
- Charger quantity and power
- Hourly or interval load profile
- Vehicle arrival/departure pattern
- Daily charging energy
- Solar capacity and generation profile
- Peak-shaving or backup objective
- Desired support duration
- Future expansion requirement
Evaluating BESS sizing for EV charging? Share your site load profile for a technical assessment.
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