HIOKI BATTERY INSULATION TESTER BT5525: Detect contamination that could cause defects.
Improve battery cell productivity through high-speed testing.


Detect contamination that could cause defects. Improve battery cell productivity through high-speed testing.

Detecting minuscule insulation defects caused by contamination (Break Down Detect function)

The BDD function is a proprietary testing function that can detect minuscule internal short-circuits caused by contamination (with metallic matter) at the stage before battery cells are filled with electrolyte. By identifying and eliminating defective parts at an early stage in the production process, the BDD function helps prevent the risk of hazards such as fires and accidents caused by heating after battery shipment. In addition, minuscule internal short-circuits in cells accelerate battery degradation. The BDD function will contribute to the production of batteries with greater durability and electrical performance.

Preventing testing do-overs due to erroneous judgments

The BT5525 provides a contact check function to determine whether the instrument has made proper contact with the circuit under test by measuring the capacitance between the measurement terminals (stray capacitance and the capacitance of the circuit under test).

Stable insulation resistance testing, even in noisy environments

Hioki succeeded in significantly reducing the effects of external noise by drawing on insulation resistance tester measurement technology and design expertise cultivated over many years.
As a result, the BT5525 can perform stable, variation-free insulation resistance testing at a level of quality that lets its detect internal short-circuits caused by contamination.


Accuracy guaranteed for 1 year
Main functions Insulation resistance test
Break Down Detect function (BDD)
Contact check function
Output specifications Output voltage : 25 V to 500 V, Setting resolution 1 V
Charging current
(Current limit function) : 50 µA to 50 mA*1*2*3, Minimum setting resolution 10 μA
Short-circuit current : 60 mA or less
Discharge current : 40 mA or greater

*1: Constraints involving the output generator will result in an error, making measurement impossible, if a capacitive load of approximately 50 μF or greater is connected while using a current limit setting of 5.1 mA or greater.
*2: When using a current limit setting of 5.1 mA or greater, measurement will be forcibly stopped if the output voltage is not at least 20 V at 200 ms after the start of measurement. Measurement will be possible 1 s after forcibly stopped.
*3: If the set current limit value is from 5.1 mA to 50.0 mA, the current will be limited to 5 mA after the output voltage reaches the set voltage.
Measurement specifications Resistance value display range : 0.050 MΩ to 9999 MΩ
Resistance range : 2 MΩ, 20 MΩ, 200 MΩ, 2000 MΩ, AUTO
Basic specifications ±1.5% rdg.±2 dgt.
25 V ≤ V < 100 V [0.05 MΩ to 2 MΩ],
100 V ≤ V ≤ 500 V [0.2 MΩ to 20 MΩ]
Time specifications Test time : 0.050 s to 999.999 s, OFF
Comparator delay time : 0.001 s to 999.999 s, AUTO
Display update speed : 1 PLC
Sampling time : 1 PLC to 100 PLC
Memory functions Panel save function : Saves up to 15 sets of measurement conditions
Measured value memory function : Saves up to 999 measured values in the instrument's internal memory
Judgment functions Test modes : Continuous test, PASS STOP, FAIL STOP
Comparator function :
UPPER_FAIL : Measured value > upper limit value
PASS : Upper limit value ≥ measured value ≥ lower limit value
LOWER_FAIL : Measured value < lower limit value
Various functions Break Down Detect function (BDD) : Detecting minuscule insulation defects caused by contamination
Contact check function : 2-terminal capacitance measurement method
Automatic data output function : Automatic output of measurement results via communication interface after completion of test
Command monitor function : Screen display of commands being sent and received
External I/O monitor function : Screen display of output signal ON/OFF and input signal status
Analog output function : Converts measured values to 0 to 4 V DC and outputs
Interfaces USB, LAN, RS-232C, EXT. I/O
Power supply 100 V to 240 V AC
Power consumption Approx. 20 VA*4

*4: Power supply conditions are 220 V supply voltage, 50, 60 Hz supply frequency, 200 V test voltage, 2 mA current limit, and load (1 GΩ resistor and 0.1 μF capacitor connected in parallel).
Maximum rated power 100 VA
Dimensions and mass Approx. 215 mm (8.46 in) W × 80 mm (3.15 in) H × 306.5 mm (12.07 in) D (excluding protruding parts), Approx. 2.8 kg (98.8 oz)
Included accessories Power cord ×1, EXT. I/O male connector ×1, EXT. I/O connector cover ×1, EXT. I/O interlock cancellation jig ×1, Startup Guide ×1