How to Replace a Hybrid Battery Step by Step Guide

The hybrid battery is responsible for supplying electrical energy to the drive wheels of your car while utilizing an electrical motor, or motors. These batteries are typical more durable than a conventional 12 volt battery, and should last over 10 years. When this battery goes bad it must be changed out with a new or rebuilt unit which will give new life to your car. Each of these hybrid battery replacements are unique, and with vary in difficulty for each application. Here is the job being done in a Toyota Prius, which will give you an idea of what need to be done, or to see what you are paying for when you car is in the shop.

Safety First

A hybrid battery deals with high voltage/amperage and if mishandled can cause injury or death so make sure to adhere to the instructions of each individual manufacturer.

Getting Started

Park the car on level ground, set the parking brake, remove ignition key or remote to avoid accidental start ups and disconnect the negative side of the conventional 12 volt, battery.

Before you begin, ensure you have the following:

• Proper Personal Protective Equipment (PPE) including gloves and safety glasses.
• Basic hand tools (wrenches, sockets, screwdrivers).
• A high-voltage battery insulation tester and a digital multimeter.
• Manufacturer-specific service manual.
• Replacement hybrid battery pack.
• A safe, flat working surface.
• A fire extinguisher rated for electrical fires.

Lets Begin

1. All hybrid cars are equipped with a hybrid battery disable safety feature which is meant to be activated during service to help prevent electrical problems, these will be in different areas of the car but typically will be close the battery and be orange in color (most cases). Once the device has been removed, wait ten minutes and the hybrid battery is now safe to handle.

2. Remove the plastic trim panels, seats and covers to expose the hybrid battery which will be in the trunk, rear hatch or under the rear seat. Be sure to keep all fasteners in a cup for safe keeping, organization helps keep the job moving smoothly.

3. An cooling air blower motor and ducts are used to reduce the temperature of the hybrid battery cells during operation, which will need to be removed.

4. Remove the low voltage, control and monitoring electrical connectors, also check the connector pins for rust or corrosion and clean as necessary.

5. There will be a cover to protect the high voltage electrical connectors which will need to be removed and is held in place by 10mm bolts.

6. Once the cover is removed it will expose the high voltage/amperage cable connections, for this next step be sure to wear the appropriate PPE (Personal Protective Equipment) to prevent exposure to hazardous electrical currents, even though the electrical has been disconnected this is a good idea. You can use a voltage meter to check for any voltage that may be present to double check the safety aspect before work continues. Use a 12mm wrench or socket to remove both cables.

7. Now, use a 12mm socket or wrench to remove the mounting bolts for the hybrid battery, there will be more than one so look around the battery to find them all.

8. Once the hybrid battery is loose from the car, use gloves to carefully lift the battery from the passenger compartment, this will be heavy so be ready, use appropriate lifting equipment or assistance, (do not drop or puncture the battery, any damage to the battery can cause it to catch fire). Clean the area free from rust, corrosion or dirt before the new battery is installed.

9. Place the old battery away for the work area, then compare the old hybrid battery to make sure the replacement hybrid battery is identical.

10. Remove the electronics and transfer them to the new battery, this may be optional depending on the application and can include the cooling fan, air ducting and relay control pod.

11. While grasping the main body of the new hybrid battery unit, gently lift it into the car while an assistant or hoist. Line up the mounting bolt holes and then start installing the bolts by hand one at a time. Once all the bolts are in you can start to tightening them down evenly in a spiral pattern, you can look up the torque spec's if needed. Complete the job by reversing the order of the steps above, reconnect all electrical connectors and sensor wires, replace the trim panels, seats, or covers removed earlier. Note: Do not over tighten the main hybrid motor power cables. Finally reconnect the 12 volt conventional battery and you are all set.

Testing and Finalizing

In some cases you will need to initialize the new hybrid battery which instructions of doing so should be included with the replace battery if needed, (In this case it was just plug and play). Before checking the new hybrid battery operation double check all of the wiring connectors, then power up the vehicle and monitor the hybrid system indicators on the dashboard for any warning lights. Finally, take the vehicle for a test drive to ensure the hybrid system operates correctly.

Watch the Video!

Please watch this video of the job being done to glean additional helpful information.

Credits

This guide knowledge base was created by the 2CarPros Team, and by Ken Lavacot: Automobile repair shop owner and certified master automobile technician of over 30 years. If you have question or need help please ask one of our experts we are happy to help. Please visit our 2CarPros YouTube Channel.