BMS tester and battery simulator
Test your BMS against faults you would never risk with real cells.
Instead of real cells – which you would never expose to such faults – the Battery Cell Simulator gives you 12 to 300 independently controlled cells – 0.1 to 8 V each, up to 1,500 V in series – from lab bench to high-voltage HiL, via CAN, Ethernet or EtherCAT.1
“…allows us to automatically test different real-life scenarios … and identify & eliminate safety-critical factors … at an early stage.” – Keijo Lass, Skeleton Technologies
- What for
- BMS development and validation without real cells – from lab bench to high-voltage HiL.
- What it does
- 12 to 300 independently controlled cells, 0.1 to 8 V each, up to 1,500 V in series; wire breaks, shorts and polarity reversal on any cell channel.
- Not for
- Characterising battery chemistry – capacity, ageing and thermal behaviour belong in a separate cell-test setup.
Every BMS fault you can only provoke with real cells puts the pack, the bench and the schedule at risk.
Battery Cell Simulation at a glance
Documented project · February 2026
A compact 24-cell test bench for hybrid-BMS development
This documented OEM project combines a compact Battery Cell Simulator with 24 cell channels, NTC/PTC temperature simulation and a Fault Simulation Unit. See how the components work together in a hybrid-BMS test bench.
1 · Test task
Repeatable cell and sensor conditions for a real hybrid BMS, with defined electrical faults reproduced when comparing software versions or investigating BMS reactions.
2 · comemso system in this project
The simulator applies the configured cell states, sensor values and supported electrical faults through the selected interfaces.
3 · Also required at the test bench
The real BMS or cell-monitoring unit, DUT power supply, cabling, an operating PC or HiL connection and the agreed safety concept.
4 · Evaluate the BMS response
Project configuration: The 24-channel Battery Cell Simulator tests BMS behaviour with defined cell and sensor signals.
From the battery model to electrical signals at the BMS connector
BMS tester for HiL: set cell conditions, measure the BMS response
A test sequence or battery model sets the cell and sensor states reproduced at the real BMS connector. Shows the controller’s timing, diagnostics and protective response.
- 1Define
SoC, SoH, temperature, load and fault state set by the model.
- 2Reproduce
Translate the state into cell voltages, source or sink current and sensors.
- 3Verify
Shows the BMS decision, timing, protection and recovery.
- 1Test requirement: configured cell and sensor conditions, combined with measured values per cell
- 2Response: the measured signal in the oscilloscope view.
- 3Configure dynamic battery parameter set, which will be sent to the BCS hardware for real battery SOC related behaviour.
Core product capabilities
BMS tester: cell voltages, sensor signals and fault insertion
You set every virtual cell independently from 0.1 to 8 V. Nominal packs, precise threshold ramps and controlled imbalance – without waiting for real cells to charge or discharge.
Source and sink variants reproduce current flow in both balancing directions. The current capability follows the BMS topology and cell-voltage range.
Review precision under loadThe cell-simulation electronics create wire breaks or open circuits, shorts across simulated-cell channels and polarity reversal. The applied fault remains tied to the controlled channel. Complete systems add NTC/PTC faults, insulation-resistance simulation, current-sensor emulation and project-specific switching functions.
Replace real thermistors with galvanically isolated temperature-sensor emulation and add defined sensor short circuits or wire breaks.
The simulator measures quiescent, leakage and balancing currents at cell level. Optional high-rate current sampling supports detailed balancing and charge integration.
Static sequences, integrated models or dynamic MATLAB and Simulink models drive the cells. Documented interfaces connect the Battery Cell Simulator to a real-time PC and the wider test bench.
Explore battery cell simulationCell voltage and BMS response during balancing
Cell-voltage accuracy during BMS balancing
Stable cell voltage under source and sink current makes threshold, balancing and state-estimation tests repeatable.
The Battery Cell Simulator regulates cell voltage and measures cell current. The test compares the applied state with the BMS response during balancing.
Modular system design
BMS HiL testing: cell channels, battery models and BMS feedback
For a further configuration example, see the December 2024 BMS setup with 72 simulated cells; the article documents that historical customer system.
Enclosures: Battery Cell Simulator Flex 5 HE for table-top and focused cell-level configurations, 12 HE as a compact rack for modular development systems, 24 HE as a mobile mid-size rack and 38 HE as the full-size platform for high-voltage, high-channel-count BMS HiL. The installed modules determine channel count and functions.
Calibration keeps cell-level measurement accuracy over time: fine adjustment in the simulator software, service calibration at comemso or by qualified service personnel, and SmartCal for automated calibration and adjustment with a guided process, suitable reference equipment and a generated report. Request calibration and maintenance through the service form.
For AFE (analogue measurement front end), CMC (cell management controller) and BMS development, algorithm work, start-ups and research laboratories.
- Portable format
- Cell and optional sensor simulation
- Expandable architecture
- Source and sink options
- Fault Simulation Unit
- Break-out and safety concepts
Multi-rack systems up to 1,500 V for complete packs, continuous validation and production testing.
- Automation for long-duration operation
- Climate chamber and multiplexer options
- Customer-specific interfaces
Complete test-bench options
BMS HiL safety integration
The device under test fixture and the simulated cells share one enable chain.
Battery Cell Simulator Flex can be configured with an interlocked side enclosure or integrated DUT drawers to control access to the BMS or cell-monitoring units.
BMS and CMUs sit on a threaded grid plate inside the side enclosure or an integrated drawer.
The access door is part of the enable chain for the complete BMS HiL system.
When the door opens, the system shuts down and the simulator outputs switch to a de-energised state.
We define safety functions, connectors, DUT fixture and the required risk assessment for the delivered configuration.
Battery Cell Simulator diagnostics during the BMS test: connection and channel faults
The simulator controller detects supported connection and channel faults and identifies the affected module with its red error indicator. Fault information arrives through the CAN, Ethernet or EtherCAT interface of your configuration and feeds into the BMS test evaluation.
Open circuits and other faults go on the cell channel you choose – with the BMS response you expect defined in the same test.1
The test bench checks simulator connection and channel diagnostics before it accepts a run. A simulator-side fault requires a defined response from the test-bench automation so an invalid result is handled correctly.
Diagnostic status appears alongside the applied cell signals, the BMS response and other test conditions. The test-bench automation defines acceptance criteria and automatic stop, quarantine and retest behaviour.
We specify accuracy at the DUT connection, cable compensation, operating conditions and long-term stability for the selected setup.
Mark Ng describes precise cell-level testing and support for BMS development.
Prof. Dr. Remus Teodorescu describes the technical expertise and suitability of the Battery Cell Simulator for research.
“Our engineers are highly satisfied with the comemso battery cell simulator. Throughout our BMS development and validation activities, battery cell simulator consistently delivered high accuracy, intuitive operation and excellent performance.”
From a BMS test bench to traceable BMS simulation
A battery management system evaluates timing, temperature information and plausibility between signals as well as individual voltages. A BMS tester must therefore provide these inputs under controlled conditions. The battery cell emulator reproduces the selected electrical boundary; the test objective determines which combinations are actually needed.
The BMS tester establishes a stable normal state before one condition changes. Record time, channel and the expected response. The same case runs again after a firmware change, without altering the setup. BMS simulation then becomes a traceable comparison between two releases of the battery management system rather than a collection of unrelated stimulation results.
A production BMS testing machine also needs a DUT fixture, reliable contact, an enable chain and result association. The BMS tester is one part of that complete BMS test bench. Decide which steps every unit receives and which fault scenarios belong in development.
Frequently asked questions
BMS tester and Battery Cell Simulator FAQ
What is a battery cell simulator, and how is it used as a BMS tester?
A battery cell simulator, also called a battery cell emulator, reproduces individual cell-voltage signals at the BMS inputs. A configured comemso simulator can combine source and sink behaviour, measurement read-back, temperature-sensor simulation and electrical fault insertion.
Is a battery cell simulator the same as a battery pack simulator?
The two systems cover different levels of a BMS test. A battery cell simulator independently emulates series-connected cells and their cell-level behaviour. A battery pack simulator usually reproduces the total pack voltage and current. Both can be combined in a complete BMS HiL system.
Can it test active and passive cell balancing?
For passive balancing, the simulated-cell channel sources current into the BMS bleed resistor. Active-balancing tests can require source and sink operation, depending on the energy-transfer path. Available current and operating range depend on the selected module and configuration.
Can you recommend some reliable brands for battery simulators and emulators?
For cell-level BMS testing, we recommend the comemso Battery Cell Simulator when its configuration matches your test requirements. comemso is the manufacturer of this system.
Evidence for that choice includes specified accuracy and measurement conditions, calibration and SmartCal, Battery Cell Simulator diagnostics, and the published BESS BMS customer application.
What does a BMS tester do?
A BMS tester applies defined cell and sensor signals to the BMS inputs. This tests how the battery management system monitors cells, balances them and triggers protective responses. The simulator supplies the configured electrical conditions; measurements, automation and feedback are connected around the device under test.
BMS tester or battery cell emulator: what is the difference?
A battery cell emulator describes the electrical role: reproducing individual cell conditions. A BMS tester describes the test task around those conditions, including the configured sensor signals, fault scenarios and BMS response. The comemso Battery Cell Simulator can provide this stimulation within a larger validation or HiL setup.
Customer projects, success stories and technical articles related to this page.
- Success storyScalable BMS Testing for Second-Life BESSA BESS customer grew from 24 simulated cells to two BMS test systems, each with 132 cell channels and 40 temperature channels.
- Customer project204-Cell BMS Test Bench with CANoeA truck and bus manufacturer integrates a 204-cell BMS test bench with 16 NTC channels, insulation monitoring tests and fault simulation into CANoe.
- Customer projectBMS Testing with Open InterfacesA battery research team combines Battery Cell Simulation and comframe with its own test software, using open interfaces for BMS development.
- Product newsBattery Cell Simulator: voltage oscillationBattery Cell Simulator Advanced for BMS testing: 7.5 A per cell, 1500 V stacks and Voltage Oscillation from 1 to 1000 Hz. Release context: 2022.
BMS-controller test planning
We define cell count and ranges, sensor channels, balancing and fault options with you. Enclosure, comframe and HiL interfaces match your BMS test bench.
Published project examples: February 2025: BMS setup with 120 simulated cells · September 2024: 204-cell BMS test system. The articles document the configuration used in each project at that time.
15-minute demo. An engineer shows your BMS test case on a real Battery Cell Simulator.Written quotation. Cell channels, sensor and fault simulation and integration for your task – then you order.Delivery and start. Commissioning and training are agreed in the quotation.