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Pleased consider the following as a thread-starter, just to get a discussion going!
One of the things I love about this forum is its frequent reminders from experts about what we CX-5 owners ought to be checking routinely and also by mileage and "occasionally".
I took note of this particular thread and several others of late because they note that several members with 2021 model CX-5s have had the 12V battery "suddenly" die. Even though I've haven't yet had any battery issues, my CX-5 is also a 2021 model that's just over four years old, I so got out my trusty Midtronics 6000 series
Battery & Conductance and Electrical System Analyzer and tested my OEM battery. Here's what the screen read with the engine off:
Voltage: 12.39 V
Measured: 426 CCA (cold cranking amps)
Rating: 550 CC (cold cranking amps)
So when I took the reading the battery was down by about 124 CCAs below its rated 550 CCAs or (124/550) 23 percent. That means, nominally at least, that it still has (550 minus 124 CCA) about 426 CCAs
I've been experimenting lately with artificial intelligence (AI), so I asked Google AI the following questions:
What is the OEM battery for a 2021 Mazda CX-5 GT, and what are its ampere-hour rating and CCA rating? What is the OEM warranty? And how long should I expect this battery to last and give me good service with my car living in South Florida and being used daily, mostly in Florida but occasionally as far away as Maine and Nova Scotia in the summertime? I like to play it safe, so when should I replace the battery and with what--best brand and group size?
Bear in mind that AI can "hallucinate" and doesn't necessarily get everything right every time--but in my experience its batting average is pretty darned good. With that caveat, here's what Google Gemini sent back in the blink of an eye. It seems pretty solid to me:
It's good you're thinking proactively about your Mazda CX-5's battery, especially with the South Florida heat! Here's a breakdown of what you need to know:
OEM Battery Specifications for 2021 Mazda CX-5 GT
Group Size: The most common OEM (Original Equipment Manufacturer) battery group size for a 2021 Mazda CX-5 GT is Group 35. Some sources also list Group 26R as a compatible size, but Group 35 appears to be the primary OEM fit.
Ampere-Hour (Ah) Rating: For the SKYACTIV-G 2.5 and 2.5T engines (which your GT likely has), the OEM battery typically has an ampere-hour rating of 12V-60Ah/20HR or 12V-65Ah/20HR.
CCA (Cold Cranking Amperage) Rating: The OEM CCA rating for a 2021 Mazda CX-5 GT typically ranges from 520 CCA to 650 CCA, with many replacements listing around 640-650 CCA. The higher the CCA, the better the starting power, especially in colder temperatures (though not as critical in South Florida, it's still a good indicator of battery strength).
Warranty: Mazda offers a 3-year/36,000-mile New-Vehicle Limited Warranty that covers the battery for total replacement if a defect in materials or workmanship is found. After the initial three years, Mazda may cover a percentage of the replacement cost for an additional two years (up to 5 years total, with the customer responsible for a pro-rated amount). This applies if the battery was dealer-installed.
Were various brands used? What brands?
While the ultimate OEM battery comes from Mazda, the actual manufacturer can vary. Mazda sources its parts from various suppliers. You'll often find that replacement batteries from reputable aftermarket brands like DieHard, Optima, Duralast, ACDelco, and Duracell are excellent choices and often meet or exceed OEM specifications. These brands will offer batteries in the appropriate Group 35 size with comparable or better CCA and Ah ratings.
How long should I expect this battery to last, with my car living in South Florida and being used daily, mostly in Florida but occasionally getting as far away as Maine and Nova Scotia in the summertime?
Car batteries typically last 3 to 5 years under normal conditions. However, heat is a battery's worst enemy, and South Florida's climate significantly shortens battery life. In hot climates like Florida, you can expect a car battery to last around 18 to 23 months (1.5 to 2 years) on average, or up to 3 years at best.
Your occasional trips to Maine and Nova Scotia in the summer will offer some relief, but the consistent high temperatures in South Florida will take their toll.
When should I replace it and with what--best brand and group size?
Given the South Florida climate, I recommend playing it safe and proactively replacing your battery at the 3-year mark. Even if it seems to be working fine, its internal components will be degrading faster due to the heat, and you don't want to be stranded.
Signs your battery is nearing its end of life:
Slow engine crank (takes longer to start)
Dim headlights or other electrical issues (especially when the car is off or just started)
Dashboard battery warning light illuminated
Swollen battery case
Corrosion around the battery terminals
Frequent need for jump-starts
Best brand and group size for replacement:
For the best performance and longevity in your Mazda CX-5 GT, consider an Absorbed Glass Mat (AGM) battery in Group 35.
Why AGM?
Better Heat Resistance: AGM batteries are more resistant to heat and vibration, which are primary causes of battery failure in hot climates.6
Longer Life: They generally last longer than traditional flooded lead-acid batteries, especially in demanding conditions.
Maintenance-Free: They are sealed and require no maintenance.
Higher Performance: They offer higher CCA and better deep-cycle capabilities, which is beneficial for modern vehicles with more electrical demands.
Recommended Brands (known for quality AGM batteries):
Optima YellowTop or RedTop (Group 35): Excellent reputation for performance and longevity, especially the YellowTop for its dual-purpose (starting and deep cycle) capabilities.
DieHard Platinum AGM (Group 35): A strong contender with good CCA and reserve capacity.
Odyssey Extreme (Group 35): Known for its robust construction and high performance.
NorthStar AGM (Group 35): Another premium option with excellent durability.
While AGM batteries are more expensive upfront, their increased lifespan and reliability in hot climates often make them a worthwhile investment. Always ensure the replacement battery meets or exceeds the OEM CCA and Ah ratings for your specific vehicle.
Remember, this is from Google Gemini. I hope it'll be a good discussion started!
As always, your mileage may vary!
Milt Baker, Pompano Beach, FL
2021 Mazda CX-5 GT, 31,000 miles
First you did not start a thread! But perpetuated a fire with more fuel
Your reader is really indicating to charge and retest. Even if it is not showing on the test result page/screen
The minimum testing voltage needs to be rested 12.50 or more
Asking the internet question will always yield the answer you want that supports your belief system as thing in your world should be. If it were that easy why have a doctor ,dentist or someone paying tens of thousands of dollars to keep a current Automotive cortication updated with the most resent and best service information available for the time?
Charge and retest!
The results for CCA should be at or above the batteries manufacture rating.
Your starting voltage measure exactly at the engine rotating should not drop more then1.5 volts
You arrested voltage should be min 1`2.50 volts and after 12 hours should not have dropped more then .75 volts. Less and the battery in declining service or you have an extremely high system or parts draw that should be looked if that is normal. To rule out battery disconnect the negative lead when tested voltage stabilized is min 12.50 and then check voltage after 12 hours.
Also DIY should occasionally test the accuracy of their testing equipment with a known accurate professional grade equipment in this case battery load tester. You would surprise how many are inaccurate.
Think of it this way 9 out of 10 vehicles on the road after the owner thinks adjusted the air properly have at least one most of the time 2 tires that are not even with the other tire on the same axle because of the air gauge not the user. Unless the user checks and fill after driving the vehcle then it is always the user. lol
Those meters that test the battery by measuring their internal resistance are very accurate but if a good electrical connection to the terminals is not made they show bad battery in many cases. I use one on every car I service and if I get a bad battery I make sure the clips are makng a good electrical connections.
The only problem with AI (the new trend word) is it has no experience.
Those meters that test the battery by measuring their internal resistance are very accurate but if a good electrical connection to the terminals is not made they show bad battery in many cases. I use one on every car I service and if I get a bad battery I make sure the clips are makng a good electrical connections.
The only problem with AI (the new trend word) is it has no experience.
not sure what you use but mine will indicate a poor connection. Time to invest in better testing equipment made in this century.
Besides the tester should first be making sure the battery leads are clean and have a good ground. The ground is IMHO the most important and often overlooked connection mostly on the chassis or frame. …
I found a picture of you on the internet. You and you Mobil service repair..
This is the one I have beeen using for abt 10 years now. Very accurate but as I said you need to make sure you have a clean connection to the battery or it will display bad readings. These units test battery, starter and alternator but there is a minor problem with mine in that it has an issue with smart alternators but still does the job. Hopefully the newer ones have software that overcomes the issue.
The old battery load tester is without a doubt the best method but having seen quiet a few open top batteries explode from incorrect use (the ten second timing) find it a tad safer to use this one.
I remember that job well.
This is the one I have beeen using for abt 10 years now.
Ten years... time for a new one. If you check it with a new one you may find it is no longer giving good information/results. Mine was about that old and it started showing new batteries as charge and re-test or batteries I know failing as good.
As for exploding batteries that has happened to me 3 times in my life I learned from those what not to do !
The old-style battery testers from about the 1990's and older do not do well (accuracy) with some of the AGM battery testing.
I see we have the same thoughts about a battery land charging system tester ?
Well to answer the statement abt comparison testing I did just that a month ago when I was at my battery supplier and I compared it with his lavish (expensive) tester and they displayed very similar readings so I'm happy to keep using it.
How is yours with smart alternators? Mine can't detect that you have revved the engine but apart from that does the job.
How is yours with smart alternators? Mine can't detect that you have revved the engine but apart from that does the job.
It works fine on at least up to 2019 Mazdas I used it on. As well other platform and did not have the rev detection issue? I have not tested my Mazda charging because I have an independent gauge to watch it. And as I mentioned I had to go make programming adjustments in the ECU for its charging rates.
Maybe this weekend I will do a test and let you know?
I have a 2021 Mazda CX-5 non-turbo, in-line 4-cylinder, automatic transmission with about 85,000 miles. I drove the car this morning with absolutely no trouble - nothing out of the ordinary. I parked it in the driveway when I got home and went about cleaning up the interior, vacuuming the floorboards, wiping down the seats, dash, and console, and cleaning the windows. When I finished, I went to put something in the back and the hatch would not open. Not even a beep.
I checked to see if the doors were locked and the button on the key fob did nothing. I tried using the door lock switch on the driver's door and there was no response. No lockey, no unlockey. Further investigation revealed that not a single electrical control in the car is working. The lights don't work, nothing. The only thing I can find on the car that is working right now is the security system activated light on the instrument panel. It's flashing every 2 seconds, just like it normally does when the engine is off. Beside that, when I push the start switch with the brake pedal down, nothing happens; but when I push the start switch without the brake, the green light on the start switch illuminates for about a second or two, then nothing. Nothing else works.
I tried disconnecting the negative terminal on the battery for about 15 minutes. I reconnected it and there was a beeping inside the car for several seconds, but no other indications on the instrument panel or anywhere else. No response from any controls. I tried disconnecting the negative cable again and reconnecting it, and got the same reaction.
Does anyone have any idea what might be going on with this car?
I had a similar problem. No electrical activity at all. I am usually fairly savvy with electronics but had to call out an expert. The battery was %100 good but they could not find anything wrong. After they left I did a quick study of the engine compartment fuse box and discovered that there are 2 fuses that are masters over all the other fuses so I pulled them only to find that they were good. When I reinserted them all of the electronics returned. I guess they had bad contacts. I now keep a couple of spares in the glove box!
Flat battery
… 
time for a new one. If you check it with a new one you may find it is no longer giving good information/results. Mine was about that old and it started showing new batteries as charge and re-test or batteries I know failing as good.
