First, be careful; this is at your own risk. I am explaining the way I did it, not in any way an expert did it and not how Mazda may do it. I took off and moved things as minimally and reasonably as I could to avoid screwing anything up. I suggest checking out a generic tutorial video online (for any car) to learn the basics for safety, etc. I also recommend reading this in its entirety beforehand and taking ‘before’ pictures of what you’ll be messing with so you know what goes where. Having said that, this is the first time I have ‘needed’ to change out my car’s 12v battery. It should be as easy as jumping a car but Mazda decided to bury half the battery further back, making the task more tedious. I don’t think the general process should change too much but FWIW, I have a 2024 CX90 Turbo S Premium Plus (MHEV) in the USA.
Tools needed: socket wrench w/ extension (was it primarily 10mm? I forget..), work gloves or bare hands (pass on cheap nitrile gloves since they will snag and get caught during battery removal and install), safety glasses (eyes are irreplaceable), and a small flathead screwdriver (for popping plastic pins along some trim). Looking back, it may be best (or maybe not?) to place your windshield wipers in service mode to give you a little extra slack to be able to move the hose around more freely.
I replaced my OEM lead acid battery (12V | 20HR | 65Ah | CCA 465A | D23) with an AGM 35 | 650 CCA | 100 Res Cap | 55Ah 12V battery (cost $180). I did this because of the endless on again/off again Battery Saving Mode alerts I’d get. Btw, I run a dash cam with parking mode but also a voltage cutoff so battery saving mode shouldn’t be happening, at least not from that. Others have recommended running an AMG battery due to how electronic-intensive the CX90 and other newer cars are, with better success. The downside you’d find online is generally the cost but it’s a worthwhile investment imo, plus you don’t need to spend hundreds (especially if you do it yourself).
Of note: the OEM battery does not have a handle on it and this is for good reason. The bracket that ultimately holds the battery down sits flush across the top of the battery; if your new battery has a handle, I suggest cutting it off before installation, though it is accessible enough to cut afterward if needed. Since this is not a clean install due to the location of the battery area, and you are working at a slight angle for the install, the handle won’t do you much good during installation anyway.
Onto the instructions (pics correspond to the respective wording above it)...
1) Removal of some paneling/trim pieces: First, pop off the blue pin in the top red circle (seen in the below pic); I found it easier to just yank the pin out of the car than to try sliding the rubber piece itself out of the blue pin—I think I squeezed the pin from below to help force it up (YouTuber “Shop Foreman Garage” has a helpful video showing these beginning steps in his “CX 90 Battery Saving Mode. How to fix this issue.” video). Then, use a flathead screwdriver to pop the black circular pin out seen in the lower red circle. Everything is getting re-used so try not to break or lose anything.
![Image]()
2) Continue with removing some of the vital stuff. Pop the washer fluid hose out, as seen in the white circles below. There may be some tugging and slight tension involved with the battery removal so A) be careful not to break it and B) I suggest popping it out across the entire way (don’t rip the hose out of the wipers…). Now, there are two more black pins to pop out, seen in the red circles below. Take your time and don’t rush anything. You don’t want to drop any pins or screws into no man’s land!
![Image]()
3) Now for the battery. Seen in the pic below with the red arrow, remove the ‘negative’ screw first. Use the black plastic trim piece above to wedge that negative connector out of the way after disconnecting it. WARNING: A bit obvious but if that piece falls back down and so much as scrapes the negative battery terminal, the battery will be hot again. Keep it out of the way and/or covered in some way. There should be no sparking whatsoever during this process if done safely and correctly. Of note, you do not seem to lose any car settings when the battery is disconnected which is nice. Take note of the battery bracket screw that holds everything down on the left (yellow arrow). This will be removed soon but not yet—let’s remove the positive terminal screw in the next step.
![Image]()
4) Go ahead and remove the positive terminal screw seen in the green circle. Note that there is a small little bracket piece that you may want to take out along with the screw, carefully. Don’t lose it.
![Image]()
5) Note the way the bracket notch faces in the picture below for when you re-seat it— facing inward, farthest from you (more importantly, just note the way you took it out).
![Image]()
6) Now you can remove the screws holding the battery and that shelled compartment down. Seen with a yellow arrow in the earlier picture and in the one below, remove the screws to the left and right of the battery compartment. This is, of course, what keeps your battery in place and secured. You really just need to loosen them, and then you can quickly remove them by hand.
![Image]()
7) You can now slide that top housing off and to the side, seen below. I didn’t see any need to remove anything else within that black/red housing, or a need to pop off that top black part. However, you may want to carefully try pulling that wiper fluid hose back, up, and over the large plastic trim it’s hanging down on so it’s not in the way (do what works for you).
![Image]()
8) Picture below with the battery out.
![Image]()
9) Install the new battery (the positive end facing the front, of course) and do everything in reverse now. It took some slight angling to work the battery into the compartment but nothing too difficult. Everything should fit like a glove when reassembling. Also as a side note, I think I had to give my car a few minutes before my power-folding mirrors folded in when I locked my car (per my user setting); they folded in with the press of a button immediately, just not from the automated user setting. So far, so good with my new AGM battery!
Feel free to add any suggestions or feedback here. Good luck!
Tools needed: socket wrench w/ extension (was it primarily 10mm? I forget..), work gloves or bare hands (pass on cheap nitrile gloves since they will snag and get caught during battery removal and install), safety glasses (eyes are irreplaceable), and a small flathead screwdriver (for popping plastic pins along some trim). Looking back, it may be best (or maybe not?) to place your windshield wipers in service mode to give you a little extra slack to be able to move the hose around more freely.
I replaced my OEM lead acid battery (12V | 20HR | 65Ah | CCA 465A | D23) with an AGM 35 | 650 CCA | 100 Res Cap | 55Ah 12V battery (cost $180). I did this because of the endless on again/off again Battery Saving Mode alerts I’d get. Btw, I run a dash cam with parking mode but also a voltage cutoff so battery saving mode shouldn’t be happening, at least not from that. Others have recommended running an AMG battery due to how electronic-intensive the CX90 and other newer cars are, with better success. The downside you’d find online is generally the cost but it’s a worthwhile investment imo, plus you don’t need to spend hundreds (especially if you do it yourself).
Of note: the OEM battery does not have a handle on it and this is for good reason. The bracket that ultimately holds the battery down sits flush across the top of the battery; if your new battery has a handle, I suggest cutting it off before installation, though it is accessible enough to cut afterward if needed. Since this is not a clean install due to the location of the battery area, and you are working at a slight angle for the install, the handle won’t do you much good during installation anyway.
Onto the instructions (pics correspond to the respective wording above it)...
1) Removal of some paneling/trim pieces: First, pop off the blue pin in the top red circle (seen in the below pic); I found it easier to just yank the pin out of the car than to try sliding the rubber piece itself out of the blue pin—I think I squeezed the pin from below to help force it up (YouTuber “Shop Foreman Garage” has a helpful video showing these beginning steps in his “CX 90 Battery Saving Mode. How to fix this issue.” video). Then, use a flathead screwdriver to pop the black circular pin out seen in the lower red circle. Everything is getting re-used so try not to break or lose anything.
2) Continue with removing some of the vital stuff. Pop the washer fluid hose out, as seen in the white circles below. There may be some tugging and slight tension involved with the battery removal so A) be careful not to break it and B) I suggest popping it out across the entire way (don’t rip the hose out of the wipers…). Now, there are two more black pins to pop out, seen in the red circles below. Take your time and don’t rush anything. You don’t want to drop any pins or screws into no man’s land!
3) Now for the battery. Seen in the pic below with the red arrow, remove the ‘negative’ screw first. Use the black plastic trim piece above to wedge that negative connector out of the way after disconnecting it. WARNING: A bit obvious but if that piece falls back down and so much as scrapes the negative battery terminal, the battery will be hot again. Keep it out of the way and/or covered in some way. There should be no sparking whatsoever during this process if done safely and correctly. Of note, you do not seem to lose any car settings when the battery is disconnected which is nice. Take note of the battery bracket screw that holds everything down on the left (yellow arrow). This will be removed soon but not yet—let’s remove the positive terminal screw in the next step.
4) Go ahead and remove the positive terminal screw seen in the green circle. Note that there is a small little bracket piece that you may want to take out along with the screw, carefully. Don’t lose it.
5) Note the way the bracket notch faces in the picture below for when you re-seat it— facing inward, farthest from you (more importantly, just note the way you took it out).
6) Now you can remove the screws holding the battery and that shelled compartment down. Seen with a yellow arrow in the earlier picture and in the one below, remove the screws to the left and right of the battery compartment. This is, of course, what keeps your battery in place and secured. You really just need to loosen them, and then you can quickly remove them by hand.
7) You can now slide that top housing off and to the side, seen below. I didn’t see any need to remove anything else within that black/red housing, or a need to pop off that top black part. However, you may want to carefully try pulling that wiper fluid hose back, up, and over the large plastic trim it’s hanging down on so it’s not in the way (do what works for you).
8) Picture below with the battery out.
9) Install the new battery (the positive end facing the front, of course) and do everything in reverse now. It took some slight angling to work the battery into the compartment but nothing too difficult. Everything should fit like a glove when reassembling. Also as a side note, I think I had to give my car a few minutes before my power-folding mirrors folded in when I locked my car (per my user setting); they folded in with the press of a button immediately, just not from the automated user setting. So far, so good with my new AGM battery!
Feel free to add any suggestions or feedback here. Good luck!
