What is different on a BYD EV
BYD electric cars run a high-voltage system of several hundred volts: the traction battery, the motor and inverter, the on-board charger, the DC-DC converter, the electric A/C compressor and the PTC heater. All high-voltage cables are orange. Many recent BYD models use BYD's Blade Battery (lithium iron phosphate cells) and the e-Platform 3.0, where several drive components are combined into one unit.
Before you start: equipment
- Insulated gloves rated for the system voltage (checked for leaks before every use), plus safety glasses.
- Insulated tools, and a multimeter rated CAT III 1000 V or better.
- Warning signs and a barrier around the car; nobody else touches it while it is powered down.
High-voltage power-off: the general order
- Switch the car off, keep the key away from the car and note any fault codes first.
- Disconnect the 12 V battery negative terminal.
- Remove the high-voltage service disconnect or fuse if the model has one, exactly as the manual describes.
- Wait the time stated in the manual so the capacitors in the inverter can discharge.
- Verify zero voltage at the point of work with your meter before touching anything.
The exact steps, connector positions and wait times differ per model, so use the Workshop Service Manual for that car. The diagnostic manual covers battery management (BMS), insulation faults and charging faults.
Common BYD EV jobs
- Insulation resistance faults and high-voltage interlock (HVIL) faults.
- Charging problems: AC charging, DC fast charging and the on-board charger.
- 12 V battery drain and DC-DC converter faults.
- Thermal management: coolant pump, heat pump and battery cooling.
Workshop manuals by BYD model
Frequently asked questions
Can a normal mechanic repair a BYD electric car?
Most mechanical jobs (brakes, suspension, steering, body) are the same as on any car. Work on the high-voltage system needs high-voltage training, the right PPE and the model-specific procedure.
What is the BYD Blade Battery?
It is BYD's battery design using long, thin lithium iron phosphate (LFP) cells built directly into the pack. It is used in many BYD electric models.
Where is the high-voltage power-off procedure for my BYD?
In the Workshop Service Manual for that model, in the high-voltage safety section. The steps differ per model.