2016+ CX-9 Owners - Have you replaced your battery yet?

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2016 Mazda CX-9 Grand Touring AWD
Calling all 2016+ CX-9 owners! Have you had to replace your battery yet? If so, how long did the battery that came with the car last? What type of battery did you go with? Did you do the install yourself and if so, were there any special procedures (like trying to keep all your radio stations)?

Thanks!
 
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Mazda CX-9 Grand Touring 2016
Still doing fine. It takes a Group 35 battery, easy to find. There are only 3 auto battery makers in the U.S., Exide, Johnson Controls, and East Penn. Each one makes a few different quality lines and many labels for marketers. (For example, Interstate auto batteries are made by Johnson Controls, NAPA by Exide.) Basically choose by the highest CCA cold cranking amps for the money or the longest warranty for the money. Or the cheapest if you don't plan on keeping the car for long. In your LA climate you don't need the long CCA, but that's an indicator of the future battery life. Battery makers make different internal constructions for warm regions and cold regions, and that isn't marked on the batteries--the right ones are shipped to the regions that need them. Somebody will say to buy an Optima battery. Those are made by Johnson Controls for very rough conditions. For ordinary driving they aren't worth their high cost.

Dealers, repair shops, and many auto parts stores will give you a free battery load test. That is a good way to tell if the battery is getting weak before it dies on you. Or if it is still going strong and you don't yet need a new one.

Batteries don't suddenly fail. They gradually deteriorate until they don't have enough capacity to crank the engine over long enough to start it and power the car's electronics. Say the battery loses 2% of capacity a month. That will be a 50 month life. Say it takes 20% capacity to crank the engine in normal temperatures. You're OK for the first 40 months, then on month 41 the battery has only 18% capacity left and it won't start the car. It "suddenly" failed. (Maybe my numbers are wrong, but I hope you get the idea.)
 
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bachman

Member
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'16 CX-9 Soul Red/Parchment , Touring
Still the orig battery in our '16 with 22,000 miles.
*That is some fascinating behind the scenes info PT brought to the forums! I second the thanks as well.

I don't know a lot of the "system" but regularly see auto stores mis-diagnosing battery or alternator issues. I say see but meant to say that I hear a lot of people steered wrong. They were told they need one but in the end, needed the other.

Since then and maybe just a bit before these stories, I got lucky and found SAMS Club has a very nice diagnostic tool, likely what PT refers to by dealer and shops that know what they are doing and have the right load tester. SAMS caught an issue with my Tribute years ago not long after I paid a pretty good sum for Pep Boys to do an alternator. I was having some issues and Pep Boys blamed the battery when I later found Sams tester showed a bad diode or few on the alternator. I never took up the challenge with the shop as I had another excuse/reason to trade it to a dealer and get the CX-7 at the time.
On motorcycle forums, I learned to test voltage at 2000 rpms (maybe 1750 to 1800 min) to see if the alternator shows output around 14.7 V and if so, that usually means the charging system is doing it's job if it's a matter of question or pinning down the battery or the alternator as a problem.
For grins a time or two each year, I'll add my little trickle charger/maintainer to the cars for an overnight just to top them off. We don't get serious cold too often in winters but the summer heat this year has been a real test. Coming up to a road trip soon, I guess this is as good a time as any to top off the battery one of these nights.
 
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Mazda CX-9 Grand Touring 2016
A simple battery vs. alternator test if the battery won't start the car:
Charge the battery. Let it sit a couple of hours. Measure the voltage on the battery with a voltmeter. Start the engine. Run the engine at a fast idle and measure the battery voltage again. If the voltage is higher with the engine running, the alternator is OK and the battery needs replacement. If the voltage is lower with the engine running, the alternator isn't doing its job; the battery is powering the car's electrics until it's depleted.

There certainly can be other problems causing the difficulties, but this is one simple test many can do at home.
 
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2016 Mazda CX-9 Grand Touring AWD
I believe after a battery swap the windows need to be rolled all the way down then up to allow the auto roll down function. Is there any special procedure in keeping memory settings when changing out the battery? Will a battery swap reset memory/radio favorites/settings, etc?
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
I believe after a battery swap the windows need to be rolled all the way down then up to allow the auto roll down function. Is there any special procedure in keeping memory settings when changing out the battery? Will a battery swap reset memory/radio favorites/settings, etc?

Unfortunately, I don't think there is. Just make a note of everything you want to keep and reprogram it after the battery swap.
 
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Canada
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2016 CX-9 GS-L
'16 at 36k km / 22k mi, still on original battery. Recent battery tests say it's still in good condition.

Honestly it's giving me the chills. Used to live in a hot climate wherein the battery dies in 2-3 yrs lol.
 
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2016 CX-9 GT
2016 78k miles. I think my battery is nearing the end of its life. I park in a garage so the car normally stays pretty warm, but I went camping in the mountains a few weeks ago and it got chilly (50F) in the mornings. There was a noticeable lag after I pushed the button until the engine turned over.
I went to Costco and got a replacement battery, which I have yet to install.
 
My boat's last set of batteries lasted 9 years. Simple group 27 lead acid from East Penn. They were always on 'shore power' so always maintained and charged.

What kills lead acid batteries is discharge. After discharge, the engine's alternator pushes energy at the battery; the charging process creates heat and some evaporation of the electrolyte (even 'maintenance free' batteries vent a little). The deeper the discharge, more re-charge is required which causes more heat and more evaporation. Once the electrolyte falls below the lead plates, oxidization begins which starts to destroy the battery pretty quickly.

In my experience on the boat, the electrolyte falls about 30% between 'full' and the the top of the lead plate after 1 season. After 3 years of not adding water, you could imagine that the lead would be exposed to oxygen which would accelerate the contamination process.

My suggestion: (1) Buy batteries that allow you to add water (e.g. Interstate) and keep them on a 3-stage tender, (2) buy AGM which will tolerate discharge sans maintenance, or (3) buy cheap batteries and replace them every 3 years.
 
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Mazda CX-9 GT 2018 White
2018 GT, 33k miles. Dealer replaced mine about two months ago after testing. It was getting weak.
 
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SF Bay Area
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'17 CX-9 Signature
Mine started to have issues in very early 2020. Car was 2017 CX-9 that was sold back in 2016.
 
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CX9
I have a 2019 GT FWD with almost 13K miles on it and live in toasty Texas and so far am still on the original battery.

I owned a 1999 Pontiac Grand Prix GTP for 11 years and the battery would die on me without warning every two years like clock work. I got to the point that I just prophylactically replaced them at about the 23 month point to avoid getting stranded.

My last vehicle before the CX-9 was a 2013 Toyota Venza Ltd that I traded in for the Mazda with the original battery and 66K miles. Go figure.
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
My 2018 CX-9 is on it's original battery. Just over 60k km (~37k mi). I've accidentally discharged the battery completely at least twice, maybe three times so far. Recharged it with a trickle charger each time and so far the battery is holding up. I'm tempted to see how long I can push this battery, lol.
 
2018 CX9 (purchased car new July 2018), 37K miles. Failed batter test Feb 7 2022.

We had a baby sitter who liked to leave the accessories on and drain the battery flat (3 times) which I suspect contributed to the premature failure.

Replaced at Mazda dealer for $225 (installed).
 
I can attest to upsizing the battery. The OEM is a group 35, we can install a group 24F. You have to modify the battery tray though. Just clip off a piece off of the front of the tray on the positive side. Dimensions of the battery are the same width and height but it’s length is about an inch or so longer. More CA because of the bigger battery. It was a worth while mod for me. OEM battery lasted me 20k miles. Not sure why. It’s cold in the morning but not that cold. Some mornings starter would just click click click. I got an group 24F AGM interstate from Costco for $160. The group 35 AGM was $5 less. It was a no brainer for me.