What measures can we adopt to avoid sudden peak current on led work lights in electric cars

To avoid burning led work lights in electric vehicles, we need to take two types of "peak current” into consideration, one is inrush current which occurs at startup of power on, the other is transient voltage surges that are spikes from electrical system of electric vehicle.

Because EVs operate with cascade high-voltage battery systems and sensitive DC-DC converters, these measures are essential for both longevity and safety.

When an LED driver ic on the aluminum PCBA is first powered on, internal electrolytic capacitors charge almost instantly, creating a massive current spike that can be 100 times the steady-state current.

To provide protection, a negative temperature coefficient (NTC) thermistor can be placed in series. At startup, it is cold and has high resistance, limiting the "gulp" of current. After it warms up from the current flow, its resistance drops, allowing efficient operation.

Adopt  LED driver ics with integrated soft-start functionality. These LED drivers gradually raise the voltage over several milliseconds rather than applying full power instantly, preventing the sudden "peak."

For higher-power LED work lights, active circuits using a MOSFET and a bypass relay are more efficient than NTC thermistors, as they eliminate the constant heat dissipation of a thermistor.

EV electrical systems can experience "load dumps" or spikes during regenerative braking or when heavy motors start to operate or stop.

Transient Voltage Suppression (TVS) diodes are also very important in circuits. They respond in picoseconds to  share voltage to the ground before it reaches the LED chips. 

For scenario often used in parallel with the power input, Metal Oxide Varistors absorb high-energy surges. They are excellent for protecting against larger, slower transients that might bypass a TVS diode.

For the purpose of DC-DC Isolation,  ensure the LED work lights are powered through an isolated DC-DC converter. This provides a physical "air gap" or inductive barrier that prevents high-voltage spikes from the main on-the-vehicle battery from reaching the 12V/24V accessory rail.

Placing a high-quality ceramic or electrolytic capacitor near the light’s power input can help smooth out minor local ripples and provide a small reservoir of current during quick voltage dips.

In electric vehicles, ensuring a low-impedance path to the vehicle chassis  is so important for surge protective devices to work effectively.

It is suggested to add a ferrite bead to the power wire, which can suppress high-frequency noise and minor current peaks induced by the switching power supply on vehicle.