Electric Drive Unit Leak Testing

The Sentinel I28 from Cincinnati Test Systems is one of the most advanced commercially available multi-functional test instruments.

This single station air flow and leak detection system has a standard valve manifold design that has been tested for more than 40,000,000 cycles. The manifold is coupled with the latest high-performance pressure transducer that enhances repeatability and precision and also decreases test cycle times. In addition to these features, a high-contrast 24-bit color TFT display offers XY graphing for flow and pressure loss.

Sentinel I28 Leak Testing Technologies

The Sentinel I28 leak detection system can be configured to suit a wide range of mass flow testing or pressure decay testing needs. The system can store up to 99 pre-programmed test sequences and includes 'Parent-Child Programing' which means it can control custom-made test sequences for multi-test applications.

Ethernet, RS232, binary, or a keypad can be used to select the test program. Evaluation of test results can be selected by users (fail/pass/fail, etc.). For test results, the output format can be configured to fulfill users’ requirements.

Pressure Decay/ Mass Flow Test Options

  • Occlusion test (pressure or vacuum test)
  • Volumetric fill leak test—IP67, IPX6 and sealed part leak test
  • Vacuum decay/ pressure decay—pressure change/ time
  • Vacuum decay/ pressure decay—with certified mass flow leak standard
  • Vacuum decay/ pressure decay—pressure change
  • Mass flow—with certified mass flow leak standard (pressure test only)
  • Mass flow—continuous, direct flow reading (pressure test only)
  • Mass flow—direct flow reading (pressure test only)

Differential Pressure Decay Test Options

  • Differential pressure decay/ vacuum decay—pressure change/time
  • Differential pressure decay/ vacuum decay—pressure change
  • Differential pressure decay/ vacuum decay—calculated leak rate
  • Differential pressure decay/ vacuum decay—with certified mass flow leak standard
  • Fixed charge fill: IP67, IPX6 and sealed part leak test

Selectable Test Parameters

  • Test pressure-level compensation (selectable on and off)
  • Rapid test
  • Modifiable environmental drift correction for each test program

Features of Sentinel I28

The Sentinel I28 single-station leak detection system has been developed to ease setup and troubleshooting for operators. The system has a small footprint (12″ x 9.25″ x 8.75″) to enable easy installation in space-constrained areas, such as wall mounting. The entire range of CTS instruments includes test result storage and password-protected program.

Advanced Features

  • XY graphing (flow, pressure, or loss)
  • Robust 32-bit processor equipped with 24-bit A/D converter
  • Language-neutral color LCD with 12 line, 480 x 272 operator display
  • Language options include English, Spanish, Korean and Chinese
  • Modular pneumatic and control packages
  • Expanded instrument control via EtherNet and IP™ communication
  • Indicator light bar detects test status—Pass/ Fail/ In-test
  • Barcode-ready input RS232 alpha-numeric string is stored with test results

Standard Features

  • Precise results are ensured by 'performance factor' calibration feedback
  • Transducer zero and span are automatically reset at the time of auto-calibration
  • Automatic calibration features mass flow leak standard certified for flow and pressure
  • Includes firmware validation documentation
  • Self-test separates the pneumatics of the Sentinel I28 to cross-check a 'no leak' condition
  • The calibration program can be manually configured

Measurement Range

Standard Test Pressure Ranges

  • A standard pressure transducer, valve manifolds and regulator ranges: −14.5, −2, −0.1 to 4″ HG, 0.5, 2, 30, 100, 200, 400, 500, or electronic regulation (PSIG)
  • Optional high cV flow valves and manifold are available in up to 100 psig range and provide five times faster fill and exhaust to decrease cycle times on huge parts
  • Low volume test manifold is available as option
  • A low volume (0.07cc) manifold is available as an option
  • Six point pressure calibration
  • Absolute pressure transducer
  • Electronic regulator available as an option with multi-point calibration
  • Data resolution is 0.00001 psi/ and scc/m

Mass Flow Sensor Ranges

Cincinnati Test Systems will improve the flow sensor and flow range of the Sentinel I28 leak testing system to fulfill the special application needs of users. Users can contact the company’s application engineering team for the available mass flow sensors.

Selectable Test Units of Measure

Units of measure can be either instrument global or according to each test program


  • PSIV
  • PSIG
  • mmH2O
  • cmH2O
  • inH2O
  • ATM
  • kg/cm2
  • mmHg
  • cmHg
  • inHg
  • Pa
  • kPa
  • MPa
  • Torr
  • Bar
  • mBar


  • scch
  • sccs
  • sccm
  • slph
  • slps
  • slpm
  • s


  • min
  • sec 
  • msec


Tooling Control

  • Part marking control
  • Up to 12 outputs and 12 inputs, with up to 5 programmable tooling motions with feedback
  • Expanded control via EtherNet and IP™ communication
  • I/O 24 VDC—optional I/O cable 'Cable, CTS, A12-610(standardx2)'
  • Tooling I/O is connected externally

Test Data Storage

  • Selectable part serialization in the test data stream
  • Up to 5000 LIFO part results, such as barcode, time, date and test results
  • Expandable download via USB port
  • Allows SPC data tracking for part traceability
  • Waveform analysis and external test data storage via the interface with the QualityWorX CTS DataHub

Electrical Requirements and Connectivity

  • Ethernet TCP/IP, EtherNet/IP, Telnet
  • RS232(2)
  • 88-264 VAC, 47-63 Hz, or 22-26 VDC (optional)
  • Barcode ready (RS232)
  • Mobile text
  • Email alerts
  • Includes ¼″ colder fitting for test line attachment
  • USB mass storage device for restore, backup and reports (FAT32 and USB1.0, 1.1, 2.0)

The World Leader in Leak Testing Equipment

Cincinnati Test Systems has over 35 years of experience in designing and manufacturing high-precision, reliable, repeatable instrumentations for complex leak test applications in manufacturing settings. The company’s application engineers will work with customers to design a customized solution that suits their requirements.

All instruments offered by Cincinnati Test Systems are CE certified and come with a two-year limited warranty. For all standard instruments, normal delivery will take two to four weeks plus delivery time.

Customers can contact Cincinnati Test Systems to receive the Sentinel I28 leak detection system or other leak testing systems.

Solving Common Electric Vehicle (EV) Battery Testing Challenges

The electric vehicle (EV) sector is a progressive market, but specifications and needs are still emerging, rendering it hard for producers of components, such as EV batteries, to develop processes and define test limits that are reliable for a high-quality product. Rigorous leak testing is also a crucial element of EV battery production.

Electric Drive Unit Leak Testing

Image Credit: Cincinnati Test Systems

The majority of the components, such as modules, cells, packs and coolant systems, in an EV battery are sensitive to leaking. Such components should be leak-tight to prevent customer inconvenience and even disastrous failure. Particularly in off-roading vehicles, battery packs should be water-tight and stop dust from entering the parts and causing safety and performance problems.

When battery components are tested, they become particularly sensitive to several issues, like barometric pressure fluctuations and temperature changes.

It is equally difficult to detect the slightest leaks in huge volume parts, such as EV batteries employed for larger commercial and passenger vehicles. Leak testing instruments demand the precision, sensitivity and traceability required to deal with the latest but major needs of EV battery testing.

Considerations for Electric Vehicle Battery Testing


  • Tracer gas is preferred over air leak testing techniques
  • Assuring cell integrity for the product life


  • Establishing the leak rate of the module cooling circuit
  • Lack of clear industry standard across manufacturers

Cooling Circuits

  • Testing the validity of circuit connections
  • Testing tubes, plates and complete cooling circuit with variable leak rates

Battery Packs

  • Lack of clear industry standard across manufacturers
  • IP67 standards are general and IP69K for adverse surroundings

Additional Challenges of Leak Testing EV Battery Packs

Among all the battery parts, battery packs represent the highest number of challenges to leak testing. The size of the component is a major problem because it is harder to consistently test huge volumes.

EV packs are prone to part expansion at irregular rates. Differences in atmospheric pressure and temperatures also have an impact on the pressure in the components, leading to differences in the test outcomes.

Flexible components and ballooning parts pose a major challenge when it comes to leak testing and can affect the outcomes unless the right equipment and test method have been selected to tackle the special challenges of the application.

Electric Drive Unit Leak Testing

Image Credit: Cincinnati Test Systems

The objective with all electric car battery testing, such as packs, is maximized cycle time, cost-effectiveness and a repeatable, reliable test with low gage R&R.

Cincinnati Test Systems has the solutions and services required by users to solve leak test issues and fulfill their EV battery testing objectives.

EV Battery Component Testing Systems

Cincinnati Test Systems has more than 35 years of know-know in providing leak test solutions for the most challenging applications in the automotive industry and beyond. The company’s leak testing systems have been demonstrated to provide repeatable and reliable testing and support engineers to improve their test cycle times without affecting the quality.

At present, Cincinnati Test Systems is using that success and knowledge to consult with manufacturers in the EV market and provides leak test instruments and services that help users define, understand and deal with EV battery leak testing standards and needs.

Sentinel 3520.

Sentinel 3520. Image Credit: Cincinnati Test Systems

Sentinel I28.

Sentinel I28. Image Credit: Cincinnati Test Systems

TracerMate II.

TracerMate II. Image Credit: Cincinnati Test Systems

Manufacturers employ the leak testing technology (such as the afore mentioned devices) of Cincinnati Test Systems to perform an array of leak and function tests to fulfill EV battery testing standards, such as:

  • Inspections of module assembly cooling circuits
  • Battery pack leak testing
  • Call/ punch leak tests
  • Cooling plate leak tests
  • Battery pack electrical connector leak tests
  • Cooling circuit hose assembly leak tests
  • Testing the finished cooling circuits before cover install
  • and more

Factors such as temperatures, leak rate, part size and part expansion do not have to delay the introduction of the EV battery, particularly when users adopt a scientific method to establish the most optimal test method.

Cincinnati Test Systems is currently working with some of the leading automotive and EV suppliers and manufacturers, providing novel, economical solutions to address those problems that keep electric vehicle battery testing engineers awake at night.

Sentinel 3520: A Leak Tester for Large-Volume EV Batteries

Detecting slight leaks in massive components is quite challenging. The Sentinel 3520 instrument has been designed with the robustness, accuracy and features required to handle an array of battery applications, in which things like bulk volume and ballooning pose problems.

The Sentinel 3520 instrument provides the sensitivity needed to consider the leak rates that are being worked by battery manufacturers, as they zero in on the right specifications for the latest application.

The leak tester performs pressure decay and flow testing for huge battery packs and trays, and also covers applications with leak rates of 15 to 20 scc/m. The Sentinel 3520 instrument has a vacuum to 95 psig range and includes complete PID loop electronic regulators.

Sentinel I28: The Right Choice for Leak Testing Battery Cooling Circuits

The Sentinel I28 system also supports differential pressure leak testing, which is perfect for low-volume and low-leak rate components, like cooling plates.

For a complete battery pack cooling circuit, the Sentinel I28 instrument offers a low-cost, user-friendly solution with excellent performance, allowing users to efficiently perform the leak test. The highly modifiable system includes a vacuum to 500 psig range and combines both with and without a PLC.

Choosing leak rates for EV cooling circuits that employ mixtures of water and glycol usually corresponds with a combustion engine cooling circuit meant for non-liquid leak rates and a test pressure that corresponds with that of its regular operating pressure.

An application like this is generally associated with pressure measurement technologies, such as the Sentinel I28 instrument. If the instrument is cooled using freon gases, then a tracer gas technology is the perfect test method for quantifying tolerable EPA release levels of refrigerant and to enable sustained system operation.

Reliable Testing to Catch Even the Smallest Leaks

With more range of off-roading and leisure vehicles going electric, leak testing of battery packs has turned out to be even more crucial to safeguard the components of batteries against aggressive off-road surroundings, which can mean being immersed in or subjected to mud, dust, water, etc. for an extended time.

In a few cases, if water happens to enter the battery pack and/ or parts, it may lead to combustion and similar problems. Hence, to ensure the best operational safety and performance in such conditions, these battery packs should be leak tested to suit the accurate needs, such as testing to IP67 standards.

To fulfill the IP67 standards, and other IP standards, leak test methods should be able to rapidly and consistently test to very low target leak rates. For EV battery cases and packs, this implies the use of a tracer gas method (TracerMate II) or a volumetric fill test with a vacuum (Sentinel I28).

Get Better Results with the Proven Solutions for EV Battery Pack Testing

Customers can contact Cincinnati Test Systems to learn more about how the company can help them with their EV battery testing requirements. At Cincinnati Test Systems, the team will help customers choose the most optimal leak testing product that suits their applications.

Cincinnati Test Systems also offers custom-designed electric vehicle battery testing equipment to address special testing challenges.

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