Fnirsi BTM-24 Multifunctional Car Battery Tester

The FNIRSI BTM-24 is an advanced, user-friendly 12V and 24V battery tester designed to replace multiple diagnostic tools. It provides a comprehensive assessment of battery health, including voltage, starting current up to 2000A CCA, state of charge (SOC), state of health (SOH), internal resistance, and the performance of the alternator and charging system. This device offers a quick and clear diagnosis, helping you determine if your battery is functioning correctly or nearing the end of its service life.

Advantages

The device utilizes a non-destructive diagnostic method, allowing you to test the battery without applying a load. It features a one-tap cranking test that records real-time voltage drops during engine start-up, as well as a dynamic charging test that monitors voltage waveforms to evaluate the alternator and voltage regulator. With its 2.4-inch color TFT display, the tester provides excellent readability in both day and night modes. The robust, insulated crocodile clips and built-in protections against reverse polarity and overvoltage ensure safe and reliable operation for both the user and the vehicle electronics.

Suitable for

• Passenger cars and motorcycles
• ATVs and golf carts
• Boats and marine equipment
• Delivery vehicles and trucks
• Professional workshops and fleet maintenance
• Used car inspections

When it may not be suitable

This device is designed for standard lead-acid, AGM, GEL, and EFB batteries and may not provide accurate results for unconventional or lithium-based battery chemistries. It is intended for diagnostic purposes and cannot repair damaged battery cells or restore a dead battery.

Key specifications

• Supported voltages: 12V and 24V
• Starting current range: Up to 2000A CCA
• Supported standards: CCA, EN, DIN, IEC, JIS, GB
• Battery types: AGM, GEL, EFB, and lead-acid
• Voltage measurement range: 6–30V
• Display: 2.4-inch color TFT
• Safety features: Reverse polarity and overvoltage protection
• Cable length: 61 cm

How to use

To begin, connect the insulated clamps to the battery terminals. Select the appropriate battery standard and type in the intuitive menu. For a health check, the device will perform a non-destructive analysis and display a status rating of GOOD, CHARGE, or BAD along with technical parameters. To perform a cranking test, follow the on-screen prompts while starting the engine to record the voltage drop. For alternator diagnostics, monitor the real-time voltage waveform while the engine is running to observe how the system responds to electrical loads.

What to consider before purchase

• Ensure your battery type is supported (AGM, GEL, EFB, or lead-acid).
• Verify that the 61 cm cable length is sufficient for your specific vehicle battery location.
• Note that the device interface is available in English and Chinese.

Usage recommendations: Always ensure the battery terminals are clean and free of corrosion before attaching the clamps to ensure accurate readings. Store the device in the provided carrying case when not in use to protect the screen and cables from damage.