prius 12v battery replacement guide at

Toyota Prius 12v Battery Guide (+ How to Replace)

A battery is an essential part of your Toyota Prius. It is the heart of your vehicle, with the most important function of starting the engine. Prius 12v battery supplies the power to the starter, control, safety, computer, and ignition system. He serves as the backbone of the car’s electrical system.

Low voltage battery in Toyota Prius Hybrid keeps all electrical systems running while the car is parked. It is done by converting the chemical into electric energy.

The typical Toyota Prius 12v battery consists of 6 cells. Each cell contains two plates; one is made from lead, other from lead dioxide. Both plates are submerged in sulphuric acid, which acts as a catalyst to trigger the plates’ chemical reaction. The chemical reaction produces electrons, which then produce electricity, and it flows from the battery to start the engine.

By switching the ignition, you signal your battery to start a chemical reaction. The engine is started, but your battery is emptied. It is then gradually recharged by a hybrid system while driving due to the reversibility of the chemical reaction. Those are the basics behind the Toyota Prius 12v battery. In the text below, you will be able to find plenty of helpful information about which 12v battery Prius uses, how to purchase it, and how to replace it.

Types of Batteries

There are several different types of batteries; the right choice can significantly impact your car’s performance.

  • Flooded batteries are lead-acid batteries primarily used in Internal Combustion Engines (ICE). They are starting batteries, which provide short, powerful bursts of power needed to start an engine.
  • AGM (Absorbed Glass Mat) batteries are slightly different types, made of fiberglass plate separator. They have a much shorter charging time and higher voltage output. They are also more resistant to vibrations, impact, and extreme temperatures. Most hybrid cars use them.
  • Deep cycle batteries are rarely used in the automotive industry because they are designed to provide long-term energy delivery. They are used chiefly as marine batteries.
  • Gel cell batteries use silica to turn the electrolyte into a gel substance. They are less tolerant of high heat and have long charging cycles. Rarely used in cars unless the manufacturer specifically calls for a gel battery.

Battery Life

Prius 12v battery is an auxiliary battery that works similarly to non-hybrids. It is used to start the engine and power car accessories.

Car batteries wear out over time; they have a finite lifespan. There are 3 key factors to affect the life of the battery – time, temperature, and vibration.

It is known that batteries gradually deteriorate until they cannot generate enough electricity to start an engine. It can take from 3 to 5 years to wear out, depending on the usage. If you use your car only on short trips, the battery may not recharge enough. Also, batteries in cars parked for more extended periods will self-discharge naturally.

Extreme heat and cold will increase the rate of battery degradation. We know that heat improves the chemical processes within the battery. Still, excessive heat will harm the battery’s sensitive components and cause the liquids to evaporate. Cold temperature (usually below the freezing point) will make it more difficult for your battery to produce the initial burst of energy to start the engine.

Preventing an excessive vibration will result in battery’s extended lifespan because it will cause internal battery parts to break down. It is essential to use special hold don hardware (nuts and bolts) to secure the battery in place. Make sure every nut or bolt is tightened correctly to prevent the battery from moving.

Battery Cost

We now know that most hybrid vehicles use AGM batteries because the onboard computer looks for a specific internal resistance of the AGM battery. If you put any other battery type, it will not charge the battery correctly, and it will fail quickly.

The cost of the AGM batteries is much higher than conventional ones simply because the cost of the materials used is higher. The glass mats that are in the cells are much harder to produce than lead-acid separator plates. Lead-acid batteries are also much easier to recycle than AGM.

With all of these factors in one place, we end up with a battery that costs around $200.

Prius 12v Battery Test

Several warning signs can tell that battery is near its end.

  • The dashboard battery light may come on.
  • Some electric accessories (radio, navigation system, windows, heaters, or CD player) refuse to function correctly.
  • The most common symptom is the car’s slow start. It will require several attempts to start, or you might only get a series of clicks.
  • Check for corrosion because it could indicate a power problem. Clean the battery terminals carefully with an old toothbrush and baking soda.
  • Also, check for battery swelling or a weird smell; it can be a sign of something wrong with the battery internally.
how to test Prius 12V battery

You can even conduct a quick battery check by performing a load test. First, you need to turn on the headlight without starting the engine. Then you leave the headlights on for 10 – 15 minutes. After that time, start your engine and watch the brightness of your headlights. If they begin to dim after the engine turns over, your Prius battery 12v does not pass the load test. If it cannot hold enough charge to support lights turned on for 15 minutes, it is time for a change.

Replacing Prius 12V Battery: Step by Step

When it comes to a battery replacement, the first thing you need to do is to find a mounting location of the 12v battery.

In Toyota Prius 1st, 2nd, and 3rd generation, it is placed in the passenger side hatch, below the cargo floor. In the 4th generation, it is located in the engine bay (driver’s side front corner).

If you find your battery dead, you can easily change it by yourself. You will need some basic tools:

  • Ratchet wrench 10 and 12mm
  • A ratchet extension, about 12mm
  • A screwdriver
  • 10mm deep socket
  • 12mm socket, shallow or deep
  • 10mm combination wrench
  • An old glove or rag

The first thing you need to do is to open the hatchback. Just keep in mind that you will lose some information like the radio presets and power window limits if you do not maintain power. It is not s major problem, but you will need another power source (another battery) if you want to avoid that.

Then you need to remove the floor mat, carpet, and the cover over the hidden plastic storage space. When you remove the plastic tire tool tray, the spare tire will remain exposed. The battery is hidden under the plastic molding on the right corner of the trunk, which then needs to be unsnapped and removed.

The air duct for the primary driving battery goes directly over the auxiliary battery, so it must be removed. There are two 10 mm bolts – one inside by the body and another down on the floor pan. Put aside the vent pipe.

It would be much easier if you move the power brake unit – you need to remove three 12mm bolts, unplug it and move it out of your way.

Then you need to access the cables by removing the plastic cap with the screwdriver. You will be able to get to the actual terminal. Lift the terminal carefully, not allowing it to touch any part of the car. Cover it with an old glove or a rag and set it out of the way.

There is a bar across the top of the battery that holds it down. Unscrew it (a 10mm bolt on one side and 10mm nut on the other) and remove it.

Then remove the negative terminal by unscrewing the 10mm bolt holding it to the car. Then set the vent tube located on the forward side of the battery out of your way. The battery can now be lifted from its place, and you can install a new one.

From this point, you do everything in reverse. Most batteries will come with sufficient charge to start the car. Still, it is advisable to drive the car for a few miles to recharge the battery as soon as possible.

12v Toyota Prius battery cost -

How to Buy Right 12v Battery?

Choosing the right battery is a crucial step because installing the incorrect battery can cause a lot of damage to your car. There are several things to consider when buying the Prius 12v battery:

  • The first thing is the battery type – in the Toyota Prius case, it is the AGM design. These batteries are highly resistant to spilling and are better able to handle repeated recharging and discharging.
  • As far as physical size is concerned, you need to check the group number for the car battery. The group number presents an industry standard that defines the battery’s physical size. Most Toyota Prius models use Group 24 or 24F.

Group 24 dimensions are: Length 10.25”, Width 6.81”, Height 8.88”

Group 24F dimensions are: Length 10.75”, Width 6.81”, Height 9.00”

  • The voltage refers to the amount of energy stored in the battery. In a fully charged battery, it is around 12.6v.
  • The current is the rate at which the charge flows and is measured in amperes.
  • CCA or the Cold Cranking Amps is also a thing to consider when buying a battery. It is a battery’s ability to start an engine at cold temperature; how much amps is the battery able to produce for 30 seconds at -170 The higher the CCA rating, the greater the starting power of the battery. Most of the car batteries have a rating of 350, 450, and 600 CCA.
  • CA, or Cranking Amps, measures how much the battery produces amps for 30 seconds, but at 00