Key takeaways
ISO 16750-2 "Electrical loads" sets out what the vehicle electrical environment does to electronic equipment: superimposed AC voltage, overvoltage, slow and steep supply voltage decrease, start voltage profiles, reverse voltage, ground offset. GB/T 28046-2 corresponds one to one. At the exploratory stage, reproduce the "start transient" and "load dump" conditions first — most intermittent restarts on the vehicle trace back to them.
The voltage of the 12 V (or 24 V / 48 V) battery on a vehicle is never a clean straight line: it drops to a few volts at start, spikes to tens of volts on a generator load dump, and carries ripple whenever a large load switches. ISO 16750-2 turns each of these into a defined test condition.
1. What the standard covers
Part 2 of ISO 16750, "Electrical loads", corresponds to GB/T 28046-2. Typical items include:
- Superimposed AC voltage: alternator rectifier ripple riding on the DC rail, which tests the filtering on the supply port
- Overvoltage: load dump and regulator failure, which tests device voltage margin
- Slow and steep supply voltage decrease: large loads switching in and line drop, the condition behind "the cluster reboots at start"
- Start voltage profiles: the transient where the starter pulls the battery down, judged by functional status class
- Reverse voltage and ground offset: reversed connection and a poor ground return
2. Functional status class is the key
The same test is judged by functional status class (A/B/C/D): class A requires full function throughout, class D allows loss of function provided the device recovers by itself afterwards. Which class applies is set by the product's safety role and the customer specification — clusters and safety-related parts are usually class A, comfort parts can be relaxed.
3. How it divides work with EMC
16750-2 covers the supply being dirty in itself; EMC standards (CISPR 25, ISO 11452) cover electromagnetic interference in space and on the harness. They are complementary: conducted emission is about not putting noise onto the harness, electrical loads is about surviving when the noise arrives.
4. How to run an exploratory round
Start by reproducing the start profile and the load dump curve on a programmable supply, and validate the protection circuit (TVS, soft start, watchdog) on the development board; set the curve parameters to the customer specification or the corresponding standard level. Electrical work is cheap and fast to iterate, which makes it a good fit for rolling runs during EVT.
Turnaround time is arranged according to the actual project. You are welcome to state your target date when submitting samples; we will check it against the current schedule, confirm a feasible plan with you, and update you at each milestone.
