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 (PCBs) at an electrostatic discharge (ESD) work station only. Hold printed circuit boards by the edges only.
Warning
ESD wrist straps
should never be worn when working with High Voltage (HV) components.
Voltages
Warning
The vehicle has low
voltage (16V) and High Voltage (HV) (400V) circuits. To fully disconnect the HV
system, refer to Service Manual procedure "Vehicle HV Disablement Procedure."
Warning
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.
Warning
Makes sure that multimeters and leads are capable of handling at least 500V before performing a procedure that involves high voltage.
Warning
Never disconnect or cut an orange high voltage power cable or HV component unless the HV system has been disabled.
Warning
After disabling the
vehicle, power is maintained for 30 seconds in the Supplemental Restraint System
(SRS) and 1 minute in the high voltage electrical system.
Warning
Never cut into the HV battery enclosure.
HV Battery and HV Circuits
The HV battery stores all of the energy for the motor and vehicle electrical systems. The HV circuits can sense a variety of conditions that could potentially damage the vehicle or pose a safety risk. Their primary response in these circumstances is to disconnect the HV from the rest of the vehicle.
When the HV battery is not in a vehicle, high voltage is not accessible without removing the ancillary bay cover.
Warning
Remove all jewelry (watches, bracelets, rings, necklaces, earrings, ID tags, piercings, etc.) from your person, and all objects (keys, coins, pens, pencils, tools, fasteners, etc.) from your pockets before performing any procedure that exposes you to high voltage.
Warning
If corrective eyewear is necessary to safely perform any procedure, make sure that the eyewear is securely restrained to the head and cannot fall off.
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.
Warning
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.
Warning
If the HV battery or vehicle displays signs of escaping gases, smoke, flames, excessive heat, sparks, or arcing, contact the local emergency department and refer to the applicable Emergency Response Guide, available at https://www.tesla.com/firstresponders. Gases or smoke exiting a lithium-ion HV battery are likely flammable and could ignite at any time.
16V Battery
The 16V battery used in 2024+ Model 3 is a Lithium-ion type like the HV
battery, yet of a much smaller form factor. The 16V battery has its own BMS.
Warning
Do not attempt to
charge the 16V battery outside of vehicle is you do not have external LV Lithium Ion
Battery Charger. Only the DCDC converter within the vehicle can safety and properly
charge the 16V battery. If a vehicle has come to service with a discharged Li-ion LV
battery; it is recommended that the battery is connected to an external LV Lithium
Ion Battery charger tool at the earliest opportunity. This will recover and recharge
the LV battery, preventing it becoming over-discharged and needing replacement while
waiting for the vehicle to be fixed.
Warning
Only charge the 16V
battery in a well-ventilated area that is free from sparks or open flame.
Warning
Keep the 16V battery
upright at all times. The 16V battery is vented (not sealed), allowing the sulfuric
acid to spill out if the battery is not kept upright.
Warning
To avoid personal
injury, use proper lifting techniques when handling the 16V battery.
Warning
Use only battery
chargers specified by Tesla. Charging the battery outside of the recommended
specification can cause the battery to overheat and increase the possibility that
acid and hydrogen gas will be released, possibly causing personal injury, damage to
the vehicle, fire, or an explosion.
Warning
Batteries can be a
source of high electrical current and can cause an electrical shock in certain
situations, such as a short circuit.
Warning
To prevent vented
gases from entering the cabin intake or corroding components, always makes sure the
16V battery ventilation tube is reinstalled after performing work.
CAUTION
The HV battery in
2024+ Model 3 will support a damaged/over discharged 16V battery whether or not the
vehicle is being driven. However, upon detection of 16V battery degradation, the
vehicle provides alerts indicating that the 16V 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 16V battery (and the vehicle
will have to be jump-started), or the 16V battery may become overheated due to
nearly continuous charging.
CAUTION
Over discharging a
16V 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" 16V
battery, always replace the 16V battery. Even if an over discharged battery is
charged again successfully, the damage incurred is likely to cause future
reliability problems.
CAUTION
Prevent unnecessary
16V battery replacement. If a vehicle is unable to support the 16V battery, or has a
low HV State of Charge and is unable to be recharged, disconnect 16V power (refer to
LV Battery - Li-lon (Disconnect and Connect)). Keeping
the 16V battery connected might result in damaging the 16V 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 make sure that it is secured.
When replacing a component, keep oily hands away from electrical connection areas.
Make sure 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.
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.
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
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 cut, drill, or weld near HV batteries.
Install plugs in each HV connection before storing the HV battery.
Note
If plugs for the HV connectors are not available, cover the connector(s) with 3M 2480S masking tape or 3M 471 vinyl tape.
HV batteries should be stored in a dry area, in approved packaging, or on non-conductive surfaces. To reduce the risk of accidental shorting, make sure that there is no loose metal or other conductive materials near stored batteries.
HV batteries should not be stored longer than 9 months since HV 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 HV 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 HV 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 HV batteries.
HV batteries contain recyclable materials. Tesla strongly encourages recycling. Tesla recommends 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 an HV battery without returning it to Tesla, consult with local, state and /or federal authorities on the appropriate methods for disposal and recycling.