(The procedure should be the same or very similar for models equipped with the 2.0L I4, the 2.5L turbo I4 and the SkyActiv-D 2.2L twin turbocharged diesel engine.)

Owners of other Mazda vehicles such as the CX-3, CX-30, CX-7, CX-9, Mazda3, Mazda6, MX-30, MX-5 Miata, Mazda2, CX-4, CX-8 and BT-50 may also find these DIY instructions to be helpful.

The OEM (original equipment manufacturer) battery is a "Group Size" 35 and the part number is Panasonic 55D23L-MF (also known as 55D23LMF or 55D23L MF).

A few compatible replacement aftermarket group size 35 12 volt car batteries with their part numbers include the following: Optima 8020-164 35 RedTop, Delphi BU9035, EverStart MAXX-35N (Walmart) and Interstate Batteries 8850242 (Costco).

The tools needed to complete this procedure include a deep well 10mm socket with a 1/4" or 3/8" drive ratchet or a standard 10mm wrench.

The first two steps are to open the hood and move to the right (driver) side of the engine bay.

Attention - Please proceed with caution and at your own risk!

The 12V automotive battery is located to the left of the primary electrical fuse / relay box, to the right of the brake fluid reservoir and right behind the engine air filter housing.

Do NOT touch both of the terminals or battery posts at the same time to avoid being electrocuted. It would be best to wear gloves and safety glasses while completing this procedure.

First, loosen the "-" negative terminal nut by turning it in the counterclockwise direction with a 10mm socket and a 1/4" drive ratchet.

You do not need to remove the terminal nut, just loosen it a few turns.

Wrap the terminal in a small towel and tuck it away on the right to help prevent accidental electrical contact.

Then loosen the two nuts on the top of the battery hold down bar or "clamp" by turning them in the counterclockwise direction with a deep well 10mm socket and a ratchet or a 10mm wrench.

You don't need to fully remove the two nuts on the hold down clamp.

Set the hold down clamp and two "J" bars aside in a safe place.

Next, flip open the plastic cover on the top of the "+" positive terminal.

Loosen the nut on the positive terminal by turning it in the counterclockwise direction with the 10mm socket and a 1/4" drive ratchet.

Close the plastic cover over the positive terminal and tuck it away on the left side of the battery.

Pull the plastic and foam heat shield box off the old battery and set it aside for reinstallation later on.

Gently set the old battery down on the ground. Try to avoid dropping or tipping over the old battery to prevent from having acid leak out.

The original battery in this 2019 Mazda CX-5 was marked as part number Panasonic 55D23L-MF.

To check the distilled water level in the old battery, shine a flashlight on the side. There are lines indicating the "Upper Level" and "Lower Level".

Be sure to take the old battery with you to the auto parts store, Walmart or Costco so you can possibly avoid having to pay a "core", "recycling" or "disposal" fee.

Orientate the new battery in the correct position.

In this 2019 CX-5, the negative battery post should be at the rear of the engine bay near the windshield and the "+" positive post should be closer to the front of the SUV near the engine air filter housing.

Carefully lower the new battery down into the engine bay.

Slide the heat shield box over the new battery.

If you've had an issue with corrosion (white, blue or green powder) building up on the terminals or posts, I highly recommend installing some felt anti-corrosion washers over the battery posts.

The felt washers are very cheap insurance against having to replace corroded terminals or cables.

Tighten the terminal nut in the clockwise direction with the 10mm socket and a 1/4" drive ratchet until it is snug.

Try to avoid over tightening the terminal nut to prevent from cracking the battery post which could result in an acid leak.

Flip the plastic cover closed over the positive terminal. You should feel or hear the cover "click" securely into place.

Avoid making contact with the terminals or battery posts.

Reattach the "J" hooks to their mounting slots on the left and right side of the battery tray.

Check to see if the new battery can be moved, slid or rocked on the battery tray.

If the new battery can be moved, tighten the two nuts on the hold down bar an extra turn or two.

Carefully push the negative terminal on to the "-" battery post.

Double check that the two terminals are securely attached.

Please remember to adjust the time on the clock and re-program your favorite radio stations before you start driving.

To test the new 12V battery, start the engine.

If you suspect that your alternator is weak or could be failing, use a digital multimeter tool to check the voltage when the engine is running.

If the alternator is working properly and charging the battery, the voltage on the battery terminals should be at least 13V to as much as just over 14V when the engine is running.

If the engine is switched off, the new battery should read at least 12 volts and about 12.6 volts when fully charged.

Be sure to write down the battery change in your SUV's service records.

Please check out all of my 2017-2022 Mazda CX-5 DIY Repair & Maintenance Guides.