I wanted to share what I found about charging the 12-volt battery on the Mazda CX-90, since it’s a common question and is basically the same idea as “How To Charge A Car Battery,” but with a few Mazda-specific notes.

First — where is the 12V battery located?

On the Mazda CX-90, the 12-volt battery is usually located in the engine bay (depending on model/trim). Even if you have a plug-in hybrid version, the car still has a regular 12V battery that powers electronics, just like other vehicles.

How to safely charge it (general process)

1. Turn the vehicle completely off

Key out

All lights and accessories off

2. Connect the charger

Connect red clamp to the 12V battery positive (+)

Connect black clamp to a clean metal ground point or negative terminal

3. Use a smart charger
   A low-amp “smart” charger is recommended. It automatically stops charging when full. Avoid high-amp “boost” modes if possible because those can stress the battery.

4. Plug in the charger
   Let it charge slowly. Some will take a few hours depending on how low the battery is.

️ Important Notes

Don’t attempt to charge if the battery looks damaged

Avoid sparks near the battery area

Make sure the charger is for 12-volt automotive batteries

Some versions of the CX-90 have safety electronics that prefer slow charging

Jump-starting vs. charging

Jump-starting only gives a temporary boost.
A charger actually restores the battery.

If the car repeatedly has low battery issues, there might be something draining power, and it’s better to have it checked by a professional.

When to get help

If you’re unsure, it’s totally okay to ask a parent, guardian, or a mechanic to assist—car batteries involve electricity and should be handled safely.

Conclusion

Charging the 12V battery on a Mazda CX-90 is pretty similar to charging any car battery:

Turn car off

Positive to positive

Negative to ground

Slow smart charging

Safety first

Hope this helps anyone who ends up searching like I did