Precharge Circuit
The precharge circuit slowly charges capacitors before the main contactors close.
What is Precharge Circuit?
It prevents large inrush currents. It uses a resistor and relay. It runs at every start. Without precharging, connecting the battery directly to the large capacitors in the inverter would create a current spike that could weld contactors or damage parts. The control unit checks that the voltage rises as expected in a short time; if not, it stops the start sequence and stores a fault code.
How it works
Voltage rises gradually through a resistor.
Why it matters for your car
Faults can stop the car starting. Codes show precharge failure.
Other terms
- Certificate Of Conformity (CoC)
- Charge Limit (State-of-Charge Target)
- Door Hinge
- Downpipe
- Driver Attention Warning (Drowsiness Alert)
- Four-Stroke Engine
- Fuel Gauge
- Gear Whine
- Head-up Display (HUD)
- Hybrid System Warning Light
- Intake Manifold
- LFP Battery (Lithium Iron Phosphate)
- OBD-II
- Rear Quarter Panel (Rear Wing)
- Steering Angle Sensor
- Trade-in (Part Exchange)
- Two-Stroke Engine
- V8 Engine
- Valve Stem Seal
- What To Do After A Breakdown