4 Essential Tools for EV High-voltage Shutdown and Reinitialization

As more people turn to electric vehicles, it's important to remember that, like regular cars, they need their fair share of maintenance to keep running smoothly. Fig. 1 shows an example of a flow for conducting service or maintenance on an EV. Before any repair or maintenance tasks, particularly during shutdown and reinitialization phases, specific electrical tests are crucial. These tests are vital due to the existence of high-voltage components such as batteries and inverters within EV systems. To ensure a safe and effective process, here are our recommended measuring instruments for conducting high-voltage shutdown and reinitialization procedures in an EV.

Fig. 1 : An example of a flow for the EV maintenance process.
  • *Disclaimer:This flow serves as an example of an EV maintenance procedure. For more details and precise information, please consult the service manual from the vehicle’s manufacturer or contact the vehicle’s manufacturer.

1. Temperature measurement

The FT3701 is an infrared thermometer with a two-point laser marker that measures the average surface temperature inside a circle formed by the two points.

Measurement temperature range-60.0 ℃ to 760.0 ℃ (-76 ˚F to 1400 ˚F)
Measurement wavelength8 to 14 μm
Thermal emissivity compensation (ε)0.10 to 1.00
Measurement field diameterφ 100 mm at 3000 mm (3.94 in. at 9.84 ft.)
(distance : spot = 30 : 1)

2. Zero-voltage measurement

DT4261 is a Bluetooth® compatible digital multimeter that can measures voltage, current, continuity, and many more. The safety features of this product make it a must-have tool for EV maintenance.

The DT4261’s terminal shutters make it physically impossible to insert the wrong test lead. They prevent overvoltage and electrical shock accidents.

DC voltage range600.0 mV to 1000 V
AC voltage range6.000 V to 1000 V (true RMS, crest factor 3 or less)
LoZ V600.0 V (true RMS, crest factor 3 or less)
Other measurement functionsDC + AC voltage, DC current, AC current, AC current with clamp-on probe, frequency, resistance, continuity, capacitance, diode test

3. Equipotential bonding test

The RM3548 is a portable 4-terminal DC miliohmmeter. The resistance measurement conducted by this meter with a measurement current ranging from 500 nA to 1 A satisfies the ECE-R-100 and ECE-R136 measurement current requirements of at least 0.2 A. The meter offers stability and precision in a wide resistance measurement range of 3 milliohms (with 0.1 microohm resolution) to 3 megaohms (with 100 ohm resolution).

Resistance range3 mΩ (0.1 μΩ resolution) to 3 MΩ range (100 Ω resolution)
Testing current500 nA DC to 1 A DC
Open-terminal voltage5.5 V DC max.
Temperature measurement-10.0°C to 99.9°C

4. Insulation resistance test

The IR4059, a Bluetooth® compatible insulation tester, spans 5 ranges (50 V to 1000 V) and streamlines EV maintenance with its safety features. For the HV range (500 V or 1000 V), additional safety measures require unlocking and voltage selection to prevent accidents. The test lead, L9788-10, featuring a remote switch and LED, facilitates convenient measurement control and real-time pass/fail assessment.

Rated output voltage50 V DC, 125 V DC, 250 V DC, 500 V DC, 1000 V DC
Overload protection600 V AC (10 s)
Response timeApprox. 0.3 second for PASS/FAIL judgement (based on in-house testing)
Other functionsIndicate MΩ measurement value after a lapse of one minute, Live circuit indicator, Automatic electric discharge, Automatic DC/AC detection, Comparator, Drop proof, Auto power save

Maximizing measurement efficiency and data management

Accommodate all of the measuring instruments in this one carrying case. This carrying case also includes the EV maintenance manual.
Fixed measuring instruments to the chassis with Z5020 to perform the measurement while checking the reading at eye level.
Installing the wireless adapter Z3210 into compatible products enables Bluetooth® connectivity, allowing instruments to connect to the GENNECT Cross mobile app. Storing and comparing data during inspections prevents potential EV electrical issues, maintaining optimal performance.


As voltage levels in EVs continue to rise, caution is increasingly necessary across various maintenance and inspection tasks. Our recommended measuring tools for EV maintenance can be used to safely perform the necessary electrical tests for conducting high-voltage shutdown and reinitialization procedures in an EV.

Explore our reading recommendations for deeper insights into specialized electrical measurements crucial for EV inspections and maintenance. Visit our product page or consult with our specialists for a comprehensive understanding of our offerings. HIOKI is dedicated to providing solutions that guarantee the secure and efficient upkeep of EVs. Take proactive steps today to safeguard the future performance of your electric vehicles.

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