Batteries are omnipresent in both the industrial world and among consumer electronics, operating in well-tuned harmonization with an array of devices and components under different contexts. For instance, a battery, while monitored by a management system or say BMS on an EV, works as the source for fundamentally all the onboard electronic devices. Then as when the battery is the load that sinks power and gets charged, its operation and charging status should be well coordinated with and by the charger to ensure safety and interoperability.

The underlying concern is, since battery tends to work in a dynamic status, how do these devices ensure their interoperability and consistency with the former while avoiding technical issues and guaranteeing safety and consistency? And of course, the answer would be connecting them with a substantial real battery against whose shifting and complex behaviours these devices’ validation can be conducted. However, is this suggestion something realistic and practical in nature?

Power electronics technologies, thanks to their evolution, have provided an outlet for this concern and what engineers can resort to, which is the battery simulator. In this article written by ActionPower, we will cover what a battery simulator is and the technical fundamentals about this versatile power testing instrument.

Charging and Discharging: Interoperation and Functional Anatomy of a Real Battery

A real battery features the bidirectionality that it can both source power for a range of devices, such as complex systems like a whole e-mobility system, or as simple as for a portable consumer device. When the battery works as a load, the battery stores power generated and transmitted to it, such as from solar energy systems and EV charging stations.

Below is a summary of a battery’s dynamic and transient operation during charging and discharging processes:

• When the battery is a load that sinks power: the battery behaves as a dynamic load with state-dependent voltage and impedance, requiring stable absorption of power transients in scenarios such as EV fast charging, regenerative energy recovery, and PV-coupled storage systems.
• When the battery is a source that supplies power:  the battery acts as a constrained power source whose voltage sag and current response under fast load changes are critical in applications like traction inverters, data centers, and consumer electronics.

To conclude further from a technical perspective, the battery’s operation is featured by the following patterns:

• State-dependent electrical behaviour: Various characteristics such as SoC, impedance, and temperature of a battery keep constantly shifting during its operation, for which a battery condition is non-repeatable.
• Fast transient response to power and load steps: Both charging and discharging involve rapid current steps, voltage sag/recovery, and CC–CV or power flow transitions that occur on millisecond-level timescales.
• Bidirectional and mode-switching operation: Batteries frequently transition between sinking and sourcing power, especially in EV, regenerative systems, and hybrid energy architectures.
• Limited controllability of internal dynamics: Electrochemical processes such as polarization, diffusion delay, and thermal coupling affect terminal behaviour but cannot be independently controlled or isolated in real batteries.
• Safety and energy constraints under transient stress: High-power transients, fault injection, or abnormal operating conditions impose significant safety risks and irreversible degradation on real battery packs, the implementation, and disposal of which are at considerable expense.

Fig 2. Summary of Shifting and Dynamic Battery Characteristics during Operation

Drawbacks of Validating with a Real Battery

With the above features and characteristics of a battery in operation discussed, we can spot the underlying challenges if a real battery is implemented for validating and testing battery-tied equipment and devices.

In the first place, the concern is about repeatability. A test bench presumably set up with a real battery cannot reliably reproduce across test cycles the same SoC, temperature, ageing, and usage history. A further challenge is that, due to the complex internal dynamics, it is technically impossible to have a specific fact isolated or independently controlled.

Cost constraints and safety place more limits on test coverage. Assuming that a test bench with a real battery is set up, all testing and validation activities including high-power transients, fault injection, abnormal charging profiles, inevitably accelerate the battery’s ageing and degradation and will eventually hit its end of lifecycle and call for costly replacement, meanwhile posing significant safety risks against these stresses.

Understanding with IEC-and-ISO-Validation Use Cases the Impracticability of Testing by a Real Battery

While the above explanations seem quite subtle for understanding why it is impractical to use a real battery for testing applications, let’s alternatively discuss this option as if in real testing scenarios as per application regulations and standards.

In OBC validation testing, standards such as IEC 61851-1 and ISO 21498-2 require charging to be evaluated under repeatable DC-side conditions, typically with output voltages of 250–450 V, defined charging currents (e.g., 32–80 A), and controlled CC–CV transitions, repeated across identical test cycles.

When a real battery pack is used, each cycle changes its state of charge, temperature, and internal resistance, leading to drift in voltage rise and CV transition behaviour. As a result, the DC-side parameters specified by the standards cannot be reproduced consistently, making real batteries unreliable for repeatable OBC testing.

Introduction to Battery Simulator, Advantages, and Its Functionality

Battery simulators are programmable power equipment that, yet in nature, combine hardware and software, with bidirectional operation capability and replicate the characteristics of a real battery under charging and discharging status. Meanwhile, they offer more flexible and powerful control methods for voluntarily and isolatedly setting up various parameters of a battery, which are interwoven with each other on a real one.

Fig 3. Battery Emulation Software and Setting Interfaces of Action 2020

The principle of battery simulator’s operation resembles a combination of a programmable DC power source and an electronic load. Nevertheless, battery simulator operates as a single platform where the behavior and electrical relations between current, voltage, and impedance are coupled with further advanced electromechanical settings like battery models and internal resistance are available for emulating intrinsic batteries in a unified control method. These features are something not available if a test bench is set up with the combination of source and load as separate testing instruments along the topology.

Discover the Technical Advantages of Battery Simulators in Lab and Testing Scenarios

In the previous context, we have discussed those drawbacks and downsides of, supposing it can be really implemented and set up within the environment, testing with a real battery. By contrast, engineers can have their minds at ease on that front when conducting testing applications with a battery simulator. Handling correspondingly those concerns, including cost, safety, controllability, and repetitiveness, a battery simulator offers the following technical advantages:

Cost-Effectiveness and Reduced Total Cost of Ownership

Battery simulators enable continuous testing without consumable energy storage elements, reducing operational overhead while supporting long-duration, high-cycle, and stress-oriented test programs.

Advanced options such as the TITAN Series Battery Simulator Power Supply (previously ABS) further allow scalability for reaching even 10 MW power levels, meanwhile uncompromising inter-system communication and operation dynamics with advanced power electronics technologies. Users do not have to replace the whole system as with old-school power testing equipment, which is unscalable and requires a repurchase in case required specifications scale up.

Fig 4. TITAN Battery Simulator Power Supply and Emulation Software by ActionPower

Programmability and Controllability

Battery simulators offer software-defined control over both electrical and behavioural battery characteristics, enabling test conditions to be configured with high precision and adjusted instantly as test objectives evolve.

Beyond basic voltage and current limits, battery behaviour can be shaped through parameterized models that describe how the terminal voltage responds to state of charge (SoC), internal resistance, load current, and dynamic operating conditions. Charging and discharging processes, including CC–CV transitions, current ramping, and operational boundaries, are fully deterministic, allowing complex test scenarios to be executed in a controlled and repeatable manner across a wide range of applications.

Repeatability

Battery simulators reproduce identical electrical conditions across repeated test runs. Defined parameters and dynamic behaviours remain stable over time, ensuring consistent results for regression testing, comparative evaluation, and standards-based validation.

Transient response capability

Designed with high-bandwidth control loops, battery simulators accurately reproduce fast electrical transients such as load steps, regenerative power flow, voltage sag, and recovery dynamics, which are critical for validating modern power electronic systems.

Coverage of extreme and abnormal operating conditions

Battery simulators support controlled injection of abnormal states, including voltage excursions, current limits, and dynamic disturbances, enabling comprehensive test coverage without compromising system safety or test continuity.

How Do Battery Simulators Enhance Safety Compliance for Industrial Testing Applications?

Battery simulators have their places across industrial compliance validations ranging from low-power testing scenarios, such as for consumer devices, up to megawatt high power contexts, including for data centers and battery energy storage systems (BESS) where a converter or PCS has to be validated.

Testing Electric Vehicles (EV) Subsystems with Emulated Battery

Testing environment setup with new energy vehicles expects a dynamic power control with transient responsiveness as if it is a vehicle in real driving status where speed constantly shifts with regenerative braking taking place in between sporadically and consecutively. Transient CC-CV charging profiles, bidirectional power flow for regenerative scenarios, programmed impedance, and realist voltage sags under load changes are all covered by batter simulators for testing engineers’ convenience to replicate real-world conditions.

• Deterministic limits: programmable OVP/UVP, current limits, power limits, and slew-rate constraints to prevent unsafe excursions.
• Repeatable charging validation: CC–CV transitions, current ramps, and voltage windows can be executed consistently for compliance-oriented test plans.
• Safe transient and regenerative testing: controlled sourcing/sinking behaviour for drive-cycle transients and regenerative events, without uncontrolled energy return.
• Fault injection without hazard escalation: defined voltage dips/steps, interruptions, and limit behaviours to validate protection functions and fail-safe responses.

High Power Testing Application for BESS (Battery Energy Storage Systems)

For BESS and PCS (Power Conversion System) validation, battery simulators provide a compliance-friendly way to test high-power bidirectional operation, grid-support modes, and protection coordination under controlled DC conditions. They enable stable emulation of battery-side behaviour while supporting long-duration cycling and abnormal-condition verification.

• Bidirectional compliance testing: stable charge/discharge operation with programmable power ramps and boundary enforcement.
• Protection and interlock verification: controlled over/undervoltage and overcurrent conditions to validate trips, interlocks, and sequencing.
• Thermal and endurance test support: repeatable profiles for long-cycle validation without physical pack handling risk.
• Abnormal condition coverage: programmable impedance and transient dynamics to evaluate DC bus stability and control robustness.

AI Data Center and UPS Continuity Testing

In AI data centers, battery simulators support safety-compliant validation of high-power DC architectures such as UPS, battery backup systems, DC bus converters, and energy storage interfaces. They enable controlled testing of ride-through events, load transients, and protection behaviours under repeatable conditions aligned with reliability and safety requirements.

• Ride-through and switchover validation: programmable voltage sag, step response, and recovery to verify UPS/DC bus stability during fast transitions.
• High-current transient control: accurate load-step emulation and current slew limits to prevent unsafe overshoot on sensitive power rails.
• Protection behaviour verification: repeatable abnormal profiles to validate OCP/OVP/UVP coordination and shutdown behaviour.
• Reduced operational risk: safer lab validation for high-energy backup scenarios without handling large physical battery strings.

Optimize Your Product’s Consistency and Safety with ActionPower’s Battery Simulators

We appreciate your attention to this article where we covered thoroughly the advantages and applications of battery simulators as well as their role in improving and proving a product’s robustness and reliability against emulated transient operation and fault conditions.

ActionPower’s portfolio of battery emulation hardware and software supports both consumer-level power testing and large-scale system validation, spanning DC power ratings from 15 kW to 10 MW. These solutions are available in multiple structural and architectural configurations, including rack-mounted modular platforms and high-power cabinet-based systems, to accommodate diverse testing requirements.

You may contact us for expert suggestions about selecting the right model or explore with our power supply wizard for identifying the correct model option, filtering by current, voltage, and power ratings.