[cmelfer]

I've owned a 2023 Mazda CX-30 since August of 2024
The wife drove until December of 2024 before the battery died. I changed it, drove it the the mall, and it died there. After a jump I drove home, charged again, and the battery died overnight.
I removed and upgraded the battery to 60AH, and in 2days (today January 4th 2025), the battery is now at 4v.
What the hell is going on???

@dclayton045
Do you use Accessory Mode? Accessory mode is the electrical system running without the engine running, i.e. listening to music while waiting for some one. This will drain the battery in less than an hour.

Do you store the fob within 5 feet of the vehicle? The fob will cycle through activating the electrical system as proximity is an indication of usage.

I, too, had batteries dying left and right. Here are the steps for stopping that.

• Stop using Accessory Mode. Never use the vehicle without the engine running.
• When finished using the vehicle: turn off the headlights manually, set the parking brake, and remove the fob from the proximity of the vehicle.

This has been an issue with Mazda CX-30 for years and Mazda has not fixed it.

 

[30pilot]

@dclayton045
Do you use Accessory Mode? Accessory mode is the electrical system running without the engine running, i.e. listening to music while waiting for some one. This will drain the battery in less than an hour.

Do you store the fob within 5 feet of the vehicle? The fob will cycle through activating the electrical system as proximity is an indication of usage.

I, too, had batteries dying left and right. Here are the steps for stopping that.

• Stop using Accessory Mode. Never use the vehicle without the engine running.
• When finished using the vehicle: turn off the headlights manually, set the parking brake, and remove the fob from the proximity of the vehicle.

This has been an issue with Mazda CX-30 for years and Mazda has not fixed it.

This has not been a problem for the majority of these vehicles. However, there is definitely something ongoing if it was doing this From day one . Obviously, there is a cause and just as assuredly the is a solution, no dealer has an explanation? Battery test reveal? Electrical system analysis futile? If a battery swap solves the problem, dealer should replace it, or the battery manufactures warranty.

 

[dclayton045]

@dclayton045
Do you use Accessory Mode? Accessory mode is the electrical system running without the engine running, i.e. listening to music while waiting for some one. This will drain the battery in less than an hour.

Do you store the fob within 5 feet of the vehicle? The fob will cycle through activating the electrical system as proximity is an indication of usage.

I, too, had batteries dying left and right. Here are the steps for stopping that.

• Stop using Accessory Mode. Never use the vehicle without the engine running.
• When finished using the vehicle: turn off the headlights manually, set the parking brake, and remove the fob from the proximity of the vehicle.

This has been an issue with Mazda CX-30 for years and Mazda has not fixed it.

Thanks! A coworker mentioned a parasitic battery drain. That was a new one on me, but it makes sense. It also gives me a direction for the dealership. The hard part will be relaying your advice to my wife. Wish me luck 🙏

 

[cmelfer]

This has not been a problem for the majority of these vehicles. However, there is definitely something ongoing if it was doing this From day one . Obviously, there is a cause and just as assuredly the is a solution, no dealer has an explanation? Battery test reveal? Electrical system analysis futile? If a battery swap solves the problem, dealer should replace it, or the battery manufactures warranty.

@30pilot
"Obviously, there is a cause and just as assuredly the is a solution."
Cause:

• Single press accessory mode (no engine) pulls about 4 amperes.
• Double press accessory mode (no engine) pulls about 11 amperes.

This drains the battery incredibly fast. If the vehicle isn't driven long enough after using Accessory the battery will not be recharged, then the battery will slowly drain oot.

Solution:
Minimize / stop using Accessory mode.

"If a battery swap solves the problem"
The battery swap is solving a symptom, not the underlying problem, which is the Accessory mode will drain the battery.

"no dealer has an explanation?"
This is a poorly designed electrical system, and the vehicle's working as Mazda designed it. Low battery will be the only trouble code that a dealer technician will see because the vehicle is operating as intended.

 

[cmelfer]

Thanks! A coworker mentioned a parasitic battery drain. That was a new one on me, but it makes sense. It also gives me a direction for the dealership. The hard part will be relaying your advice to my wife. Wish me luck 🙏

Good luck!

We had the CX-30 as a lease and thought about buying it, but after the 2 replaced batteries and the voodoo shutdown routine, we couldn't buy the vehicle. I couldn't even loan the vehicle to friends as I was afraid they would end up stranded just like us.

 

[dclayton045]

@30pilot
"Obviously, there is a cause and just as assuredly the is a solution."
Cause:

• Single press accessory mode (no engine) pulls about 4 amperes.
• Double press accessory mode (no engine) pulls about 11 amperes.

This drains the battery incredibly fast. If the vehicle isn't driven long enough after using Accessory the battery will not be recharged, then the battery will slowly drain oot.

Solution:
Minimize / stop using Accessory mode.

"If a battery swap solves the problem"
The battery swap is solving a symptom, not the underlying problem, which is the Accessory mode will drain the battery.

"no dealer has an explanation?"
This is a poorly designed electrical system, and the vehicle's working as Mazda designed it. Low battery will be the only trouble code that a dealer technician will see because the vehicle is operating as intended.

Thanks. That's good insite

 

[bobalew]

Sounds like the sort of "fun" I had with my TNGA 2020 Toyota Corolla SE sedan. Pretty much everyone who has battery drain/failure problems with their newer-tech vehicles (any make/model), usually has them go away when they replace the stock, lower-end flooded-cell OEM batteries with a quality, modern 650-680 CCA AGM battery. Yes, it sucks that you have to shell out an extra $200-300 bucks to replace what shouldn't need replacing on a new car, but it is what it is & that is how automakers roll to cut costs (they do the same thing with mediocre, lower-end tires). Another factor is vehicle software updates that aren't automatically rolled out in a proper fashion by automakers to help fix earlier software versions that had more parasitic draw from all the tech-bloat in newer vehicles. You are pretty much left to your own devices to research what updates are available & then ask/push for them during a service visit to dealership.

You are so rite. These are the times we live in.

 

[30pilot]

@30pilot
"Obviously, there is a cause and just as assuredly the is a solution."
Cause:

• Single press accessory mode (no engine) pulls about 4 amperes.
• Double press accessory mode (no engine) pulls about 11 amperes.

This drains the battery incredibly fast. If the vehicle isn't driven long enough after using Accessory the battery will not be recharged, then the battery will slowly drain oot.

Solution:
Minimize / stop using Accessory mode.

"If a battery swap solves the problem"
The battery swap is solving a symptom, not the underlying problem, which is the Accessory mode will drain the battery.

"no dealer has an explanation?"
This is a poorly designed electrical system, and the vehicle's working as Mazda designed it. Low battery will be the only trouble code that a dealer technician will see because the vehicle is operating as intended.

It seems the electrical system was adequate at one time but has become overwhelmed by tech. The system is still adequate IF users understand that "accessory mode" is not a continuous power supply, it never was either, we were cautious decades ago. Still, owners report that a battery upgrade solves their problems.

 

[jimdickert]

If we traded cars hummm?Don't think his Cx-30 would have the same problem as I have.
I know people on here are trying to help but if you are driving your car Local a few days a week(15-50 miles per trip}
there is NO reason to have to hook up a battery maintainer and I am sure most on here will say the same?

but if you do you would likely find as I have with almost every trip, the car doesn't recharge the battery 100% in that number of miles.

 

[30pilot]

but if you do you would likely find as I have with almost every trip, the car doesn't recharge the battery 100% in that number of miles.

Depends, is the car driven 15 to 50 miles continuously, or numerous intermittent local trips that add up. However, 15 miles may not charge up a particularly low battery. Our car sat in an unheated garage from Nov 2nd to Jan 6th, without a battery minder, and it started right off, drove 71 miles 35* one way and return, back in the garage.

 

[Sr Gusserman]

@johnnyseconal
Have you been using the accessory mode at all on the CX-30? The accessory mode, i.e. only electronics, will drain the battery on the CX-30 very quickly. A single press or a double press will drain the engine quickly. Example: Sitting in the car listening to the radio without the engine running will drain the battery pretty quickly.

Do not use the the Accessory Mode and the battery will last. For good measure, shutoff the headlights manually and apply the Park Brake before leaving the vehicle. I never had a problem once I stopped using the Accessory mode.

Oh yeah, ensure that the key fob is not stored close to the vehicle because a key fob in close proximity to the vehicle will periodically put the electrical system into a standby mode. Example: The car is parked in the garage and the keys are hung on the wall 5 feet from the vehicle.

Get yourself a couple of Faraday bags for your key fobs that way it blocks the signal between your car and the key fob. Also it makes the batteries on your key fob's last longer. You can get them on Amazon for a good price. Or wherever you want get them.

 

[lawur2]

@johnnyseconal
Have you been using the accessory mode at all on the CX-30? The accessory mode, i.e. only electronics, will drain the battery on the CX-30 very quickly. A single press or a double press will drain the engine quickly. Example: Sitting in the car listening to the radio without the engine running will drain the battery pretty quickly.

Do not use the the Accessory Mode and the battery will last. For good measure, shutoff the headlights manually and apply the Park Brake before leaving the vehicle. I never had a problem once I stopped using the Accessory mode.

Oh yeah, ensure that the key fob is not stored close to the vehicle because a key fob in close proximity to the vehicle will periodically put the electrical system into a standby mode. Example: The car is parked in the garage and the keys are hung on the wall 5 feet from the vehicle.

Mazda dealers have a free firmware update that will fix your problem. I had it also. MX-30's are AWFUL about battery usage but the firmware update helps a lot, though it doesn't cure it completely. Ignore those here who tell you to put your fob in a faraday package. That's baloney for the overall problem. Been there. Done that with these CX-30s.

 

[lawur2]

I am having the same problem. This time when i took my car in to be serviced the car wouldn't start. So they checked the battery and it was ok but when they put it in the car the same thing happened. So they told me my battery needed to be replaced at my expense. Which i have a problem with because when I took my car in the battery was fine. Now it's dead. And I have to pay 300 dollars to get it fixed. That doesn't seem right..plus they said my extended warranty does not cover a battery.

Mazda dealers have a free firmware update that will fix your problem. I had it also. MX-30's are AWFUL about battery usage but the firmware update helps a lot, though it doesn't cure it completely. Ignore those here who tell you to put your fob in a faraday package. That's baloney for the overall problem. Been there. Done that with these CX-30s.

 

[lawur2]

My Mazda Cx-30 had to be TOWED into Mazda for the 5th time.
After a week they replace the battery for the second time and
they also said that I had a bad battery cable that had to be replaced.
My car has 1700 miles on it and 9 months old(2023 CX30}
I feel Mazda know many of their cars have a BAD Battery Drain buttt will not fix it since I am sure it
would cost them more to find the problem...........

Mazda dealers have a free firmware update that will fix your problem. I had it also. MX-30's are AWFUL about battery usage but the firmware update helps a lot, though it doesn't cure it completely. Ignore those here who tell you to put your fob in a faraday package. That's baloney for the overall problem. Been there. Done that with these CX-30s.

 

[lawur2]

As I read this I keep thinking about the dealership's technicians, I have been where they are at in the past, "The Customer is Always Right". That's definitely a good perspective and it reminds people in the service sector how important it is to do everything they can to take care of the customer, even if they lose for having tried. In practice they will win many more times than they lose. But when one of those few occasions occur when they do lose it stings badly, events like this have even driven potentially great technicians from the career. A talented, knowledgeable and experienced technician can easily figure out what is happening here, and this has been discussed in several responses. The problem is nothing good will come from attempting to educate the vehicle owner and truthfully tell them how to make this symptom go away and from there get great service from the vehicle.

I have a 2007 Mustang GT Convertible. It doesn't get out of the garage unless the weather is perfect for taking it for a cruise with the top down. This year, getting it ready for having some fun I have installed a new battery. It did develop a parasitic drain late last summer that had pulled the battery down. The CD player wouldn't allow the radio to turn fully off due to a failed switch. It's an annoyance, but nothing that a company up in Syracuse NY couldn't handle for me. Upon re-installing the radio after it was repaired and replacing the ten year old battery that was actually still working I also decided it was time to upgrade the maintainer. This is what I have installed. Amazon.com: 12V / 6V Battery Trickle Charger Maintainer, 1.5A Automatic Smart Float Charger Battery Charger for Motorcycle Lawn Mower Car Boat Tractor ATV, SLA VRLA Gel Cell AGM Lead Acid Batteries : Automotive

The battery maintainer doesn't have to be used every time the car is parked. I only need to use it when I expect the car won't be used for a few weeks or more. Without the maintainer the battery never would have survived to be ten years old, let alone tolerate getting fully depleted like it did when the radio acted up last year. I fully expect this new battery to last at least another ten years.

Now I get it, if your situation is such that you don't have a garage and an easy way to connect up while the car isn't being used that's a problem. But it's not the car's fault that is the case. BTW, proving if there is a parasitic drain is easy for top technicians. I did this video a few years ago showing more than one routine that can be done. I would expect that the dealership's technicians can do pretty much the same. If the car is presented and a drain is detected they should be able to both prove it is present and find it. If no drain is occurring, they would be able to prove that too just like the video demonstrates.
Parasitic Drain Test (youtube.com)

You would have one other option if you chose to try something. A battery disconnect system. There are a number of options to choose from. Here are just a few examples.
Amazon.com: Top Post Knife Blade Master Switch, 12V 24V Battery Disconnect Switch for Auto Car RV-Marine Boat Truck Vehicle, Battery Cut Off Shut Off Switch (Negative,Vertical) : Automotive

Amazon.com: Remote Battery Disconnect Switch Upgraded Kill Switch for Car Truck DC12V 200A Remote Control Anti-Theft Prevent Battery Drain Isolator (Black Negative Wire at The Bottom)(360A Starting Current) : Automotive

Amazon.com: 12-48V Master Battery Disconnect Switch, High Current 200A Battery Power Cutoff Isolator Killer Switch with Face Plate for Car Vehicle RV Truck Boat Marine Outboards ATV On/Off Battery Isolator Switch : Automotive

I would point out however that if this kind of a solution fails to keep the battery from dying, then you are right back to the way you use the car pulls power from the battery and is insufficient to replace it. If that's the case, no technician can "fix" the car because it isn't broken.

Get the free Mazda firmware update for the CX-30. Your entertainment system is staying on all the time, even when you think its off. The update stops that.

 

[Sr Gusserman]

It seems the electrical system was adequate at one time but has become overwhelmed by tech. The system is still adequate IF users understand that "accessory mode" is not a continuous power supply, it never was either, we were cautious decades ago. Still, owners report that a battery upgrade solves their problems.

That's the downside of having too many bells and whistles they are nice, but they come at a price.

 

[30pilot]

That's the downside of having too many bells and whistles they are nice, but they come at a price.

It's called resource management.

 

[SDH]

Get the free Mazda firmware update for the CX-30. Your entertainment system is staying on all the time, even when you think its off. The update stops that.

The vehicle should be able to update itself automatically in this regard without ever having to deal with a crappy dealership for the update(s). Hell, even my $120 router updates its own firmware automatically.

 

[cmelfer]

Mazda dealers have a free firmware update that will fix your problem. I had it also. MX-30's are AWFUL about battery usage but the firmware update helps a lot, though it doesn't cure it completely. Ignore those here who tell you to put your fob in a faraday package. That's baloney for the overall problem. Been there. Done that with these CX-30s.

Whoa! Thanks for the information, the dealership didn't offer that at all! I had asked about firmware updates, but the dealership was unhelpful by telling me not to have the updates. I pressed them, but the firmware update didn't seem to target the entertainment system/body controller and they were going to charge ~$200.

What's ridiculous is that I was still tempted to buy out the lease because everything else was great about the CX-30, but realized we couldn't deal with the stress of possibly having a dead battery.