GB/T 45797-2025Road vehicles—Low-voltage electrical system performance requirements and test methods (English PDF)

5.1 Static current

Obtain the static current of the vehicle and each controller; check for any non-designed static current; assess whether the vehicle meets the transportation time requirements and starting requirements after long-term storage. After testing according to 6.5, the vehicle static current, the static current of controllers and other components, the vehicle static current under different usage scenarios shall not exceed the design value.

5.2 Electrical balance

Obtain the relationship between energy generation and consumption between the battery, generator or DC/DC converter, and electrical loads; assess the rationality of the power system selection. After testing according to 6.6, the SOC change and transient voltage of lead-acid batteries shall meet the requirements of Table 1. Other battery requirements can be determined through negotiation between the supplier and the buyer.

5.4 Vehicle withstand voltage variation

5.4.1 DC power supply voltage range

Inspect the performance of each vehicle component within the minimum and maximum power supply voltage range. After testing according to 6.8.2, the functional status of each vehicle component shall meet Class A as defined in GB/T 28046.1.

5.4.2 Overvoltage

5.4.2.1 Prolonged overvoltage

Simulate the output voltage rise caused by power supply system failure. After testing according to 6.8.3.1, the functional status of each vehicle component shall meet Class C as defined in GB/T 28046.1.

5.4.2.2 Auxiliary starting overvoltage

Simulates the excessively high voltage input to various components of a 12 V vehicle system during auxiliary starting. After testing according to 6.8.3.2, the functional status of each vehicle component shall at least reach Class D as defined in GB/T 28046.1; it may be required to reach a more stringent Class B if necessary. This requirement applies to vehicles with a 12 V low-voltage power supply system.

5.4.2.3 Instantaneous overvoltage

Simulates the effect of a disconnected load connection or load current injection on the vehicle in the power distribution system. After testing according to 6.8.3.3, the functional status of each vehicle component shall meet Class A as defined in GB/T 28046.1.

5.4.3 Superimposed AC voltage

Simulates the ripple voltage that occurs under DC power supply. After testing according to 6.8.4, the functional status of all vehicle components shall meet the Class A definition of GB/T 28046.1.

5.4.4 Slow voltage drop and rise, slow voltage drop and fast voltage rise

5.4.4.1 Slow voltage drop and rise

Simulates the voltage changes during the gradual discharge and charging of a battery.

Test according to 6.8.5.1. When the voltage is not lower than USmin specified in Table 7 or Table 8, the functional status shall reach Class A as defined in GB/T 28046.1. When the voltage is lower than USmin specified in Table 7 or Table 8, the functional status shall at least reach Class D as defined in GB/T 28046.1.

5.4.4.2 Slow voltage drop and fast voltage rise

Simulates the voltage change of a battery gradually discharging and rapidly recovering to the maximum supply voltage (USmax). The test shall be conducted according to 6.8.5.2.

When the voltage is not lower than USmin specified in Table 7 or Table 8, the functional status shall reach Class A as defined in GB/T 28046.1; when the voltage is lower than USmin specified in Table 7 or Table 8, the functional status shall at least reach Class D as defined in GB/T 28046.1.

5.4.5 Transient changes in supply voltage

5.4.5.1 Transient drop in supply voltage

Simulates the instantaneous voltage drop caused by the blowing of a conventional fuse in other circuits. After the test is conducted according to 6.8.6.1, the functional status of all vehicle components shall at least reach Class B as defined in GB/T 28046.1.

Whether a drop to Class C is permissible may be determined through negotiation between the supplier and the buyer.

5.4.5.2 Reset characteristics

This test examines the reset performance of various vehicle components under different voltage drops. The test shall be conducted according to 6.8.6.2. For equipment with a reset function, the functional status shall at least reach Class C as defined in GB/T 28046.1.

5.4.5.3 Starting characteristics

This test examines the performance of various vehicle components during vehicle startup. The test shall be conducted according to 6.8.6.3. The functional status of relevant equipment operating during vehicle startup shall reach Class A as defined in GB/T 28046.1. Other functions shall be determined according to Table 3 or Table 4 in GB/T 28046.2-2019. This test is not required for low-voltage power supply systems without a low-voltage starter.

5.4.6 DC/DC superimposed square wave

Simulate DC/DC output voltage changes. After testing according to 6.8.7, the functional status of each vehicle component shall meet Class A as defined in GB/T 28046.1. This test is not required for low-voltage power supply systems without DC/DC.

5.4.7 Short-term power interruption

5.4.7.1 Interruption time variation

Test the performance of short-term power interruption for each vehicle component under varying interruption time conditions. Test according to 6.8.8.1. When the interruption time tmicro <= 100 µs, the functional status of each vehicle component shall meet Class A as defined in GB/T 28046.1; when the interruption time tmicro > 100 µs, the functional status of each vehicle component shall at least reach Class C as defined in GB/T 28046.1.

5.4.7.2 Recovery time variation

Test the performance of short-term power interruption for each vehicle component under varying recovery time conditions. After testing according to 6.8.8.2, the functional status of all vehicle components shall at least reach Class C as defined in GB/T 28046.1.

5.4.8 Long-term power interruption

Test the performance of all vehicle components under long-term power interruption.

Test according to 6.8.9. After power is restored, no unexpected current fault codes shall appear; the functional status of all vehicle components shall at least reach Class C as defined in GB/T 28046.1.

5.5 Inductive load shutdown

Test the impact of voltage pulses generated at the moment of inductive load shutdown on the vehicle's power supply and functions. After conducting the test according to 6.9, the following requirements shall be met:

a) The voltage fluctuation during the inductive load turn-off process shall meet the requirements of Class IV in the transient waveform grading table B.3.7 of GB/T 21437.2-2021;

b) The functional status of the components related to the tested load shall conform to Class A as defined in GB/T 28046.1.

5.6 Load dump

5.6.1 Load dump interference under general operating conditions

This test examines the impact of voltage pulses generated during load dump under different battery SOC and engine speed conditions on the power supply system, network system, various vehicle functions. This test does not apply to electric vehicles, but electric vehicles can refer to this test. After testing according to 6.10.1, the following requirements shall be met:

a) The peak value and duration of the voltage pulse generated during load dump shall meet the requirements of Table 2. An example of the load dump pulse waveform […]