Electrical Precautions

  • 2023-05-01: Updated HV battery storage temperature guidance.

General

Avoid getting grease on electrical components and connectors. Grease collects dirt, which can cause electrical tracking (short-circuits) or high resistance.

Handle printed circuit boards at an electrostatic discharge (ESD) work station only. Wear an antistatic wrist strap and hold printed circuit boards by the edges only.

Voltages

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Warning
The vehicle has low voltage (15V) and high voltage (400V+) circuits. The High Voltage (HV) system can be energized any time the 15V battery and first responder loop are connected. To fully disconnect the HV system, refer to Service Manual procedure 17010000, Vehicle Electrical Isolation Procedure.
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Only technicians who have been trained in High Voltage Awareness and have completed all required certification courses (if applicable) are permitted to perform this procedure. Proper personal protective equipment (PPE) and insulating HV gloves with a minimum rating of class 0 (1000V) must be worn any time a high voltage cable is handled. Refer to Tech Note TN-15-92-003, "High Voltage Awareness Care Points" for additional safety information.
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Warning
Make sure that multimeters and leads are capable of handling at least 500V before performing a procedure that involves high voltage.
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Warning
Never disconnect or cut an orange high voltage power cable or high voltage component unless the HV system has been disabled.
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After disabling the vehicle, power is maintained for 90 seconds in the SRS system and 1 minute in the high voltage electrical system.
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Warning
Never cut into the HV battery enclosure.

HV Battery

The HV battery stores all of the energy for the motor and vehicle electrical systems. The battery can sense a variety of conditions that could potentially damage the vehicle or pose a safety risk. Its primary response in these circumstances is to disconnect the high voltage from the rest of the vehicle.

When the battery is not in a vehicle, high voltage is not accessible without removing the enclosure cover.

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Always remove the HV battery before performing any procedure that might require using a drill near the HV battery, especially drilling downward from inside the vehicle.
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An HV battery poses a significant high voltage and electrocution risk if the outer enclosure or safety circuits have been compromised or have been significantly damaged.
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If the battery or vehicle displays signs of escaping gases, smoke, flames, excessive heat, sparks or arcing, contact the local emergency department and refer to the First Responder Guide, available at http://www.tesla.com/firstresponders and/or the Lithium-Ion Battery Emergency Response Guide, TN-13-16-007. Gases or smoke exiting a lithium-ion HV battery are likely flammable and could ignite at any time.

15V Battery

The 15V battery used is a Lithium-ion type like the HV battery, yet of a much smaller form factor. The 15V battery has its own BMS.

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Warning
Do not attempt to charge the 15V battery outside of the vehicle. Only the DCDC converter within the vehicle can safely and properly charge the 15V battery.
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Batteries can be a source of high electrical current and can cause an electrical shock in certain situations, such as a short circuit.
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To avoid personal injury, use proper lifting techniques when handling the 15V battery.
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CAUTION
The HV battery will support a damaged/over discharged 15V battery whether or not the car is being driven. However, upon detection of 15V battery degradation, the vehicle provides alerts indicating that the 15V battery needs replacement. If these alerts are ignored for a considerable period of time, the HV battery can become discharged to the point of no longer supporting the 15V battery (and the vehicle will have to be jump-started), or the 15V battery may become overheated due to nearly continuous charging.
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CAUTION
Over discharging a battery can cause permanent damage to the battery and increase the likelihood of overheating during charging. If a vehicle has an over discharged or "dead" 15V battery, always replace the 15V battery. Even if an over discharged battery is charged again successfully, the damage incurred is likely to cause future reliability problems.
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CAUTION
Prevent unnecessary 15V battery replacement. If a vehicle is unable to support the 15V battery or has a low State of Charge (SOC) and is unable to be recharged, disconnect LV power (refer to procedure). Keeping the 15V battery connected on these vehicles might result in damaging the 15V battery through over-discharge.

Electrical Connectors and Harnesses

  • Never pull on a wiring harness to disconnect an electrical connector.
  • Never use tools to force connectors apart.
  • Ensure that disconnected connectors and sensors are protected from oil, coolant, water, or other contaminants.
  • Ensure that electrical items are dry and free of oil or grease before disconnecting and connecting test equipment.
  • After reconnecting an electrical connector, lightly pull on it to ensure that it is secured.
  • When replacing a component, keep oily hands away from electrical connection areas.
  • Ensure that any protection (cover, insulation, etc.) is replaced if disturbed.

Grease for Electrical Connectors

Some underhood and underbody connectors might be protected against corrosion by the application of a special grease during vehicle assembly. Apply the appropriate grease when repairing or replacing these connectors. Do not use other greases. Incorrect greases can migrate into relays, switches, etc. contaminating the contacts and leading to intermittent operation or failure.

Do not apply grease to any connectors that do not have grease applied from the factory.

First Aid Measures

Seek immediate medical assistance if an electrical shock or electrocution has occurred or is suspected.

Under normal conditions, technicians are not exposed to the contents of the HV battery cells. If materials from a ruptured or otherwise damaged battery contact skin, flush immediately with water and wash the affected area with soap and water. Avoid inhaling any vented gases. If a chemical burn occurs or if irritation persists, seek medical assistance. For eye contact, flush with significant amounts of water for 15 minutes and see a physician immediately.

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Warning
An HV battery poses a significant high voltage and electrocution risk if the outer enclosure or safety circuits have been compromised or have been significantly damaged.
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Warning
Avoid contact with gases escaping from a damaged battery. Vented gases might irritate the eyes, skin, and throat. Vent gas temperatures can exceed 600 ºC (1,110 ºF). Contact with hot gases can cause burns.

HV Battery Storage Precautions

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Warning
  • Do not store HV batteries below -20 ºC (-4 ºF).
  • Do not store HV batteries for over 10 days above 40 ºC (104 ºF).
  • Do not charge or discharge an HV battery below 0 ºC (32 ºF).
  • Do not store HV batteries for over 30 days at full state of charge (SOC) or completely discharged.
  • Do not weld near HV batteries.

HV batteries should be stored in a dry area, in approved packaging or on non-conductive surfaces. To reduce the risk of accidental shorting, ensure that there is no loose metal or other conductive materials near stored batteries.

HV batteries should not be stored longer than 9 months since battery service life likely will be affected. If longer storage is anticipated, contact Tesla for instructions.

HV Battery Disposal Procedures

The lithium-ion cells contained in the battery do not contain heavy metals such as lead, cadmium, or mercury.

HV Batteries should be disposed of or recycled in accordance with local, state, and federal regulations. Regulations regarding disposal of batteries vary by jurisdiction. In the United States, batteries are classified as Universal Waste, and in addition, many individual states have specific regulations regarding disposal of batteries.

HV batteries contain recyclable materials. Tesla strongly encourages recycling. Tesla recommends that that all HV batteries be taken to a Tesla Service Center so that the batteries can be evaluated, and, if appropriate, be recycled in a safe and efficient manner.

If disposing of a battery without returning it to Tesla, consult with local, state and /or federal authorities on the appropriate methods for disposal and recycling.