My current original battery has after 5 years usage weakened. Replacement offers are very confusing. Some advise the use a cheaper EFB type whilst others go for an AGM type. My manual does’t explicitly prescribe a certain type. I prefer however an EFB battery but am unsure about the risks. Who can advise?

 

Wow, I'm surprised you got that long, my 2020 OEM battery didn't last two years.
I would suggest that you purchase the best compatible battery you can afford.
The format type is generally a personal thing, though AGM batteries seem to have better specs and reviews that most other formats.
EFB are supposedly designed for stop/start systems, you didn't say if your 2018 is equipped with that feature.

 

Dear Lobstah. Thanks for your reply. Mine has stop and start. So you advise EFD.

 

Sorry. EFB.

 

I don't personally advise an EFB, and I never replace the OEM battery in any vehicle with another OEM battery, I always upgrade to a better one.
The general consensus out there is the EFB is better for start/stop systems though I have seen no actual studies that show this to be fact, but that doesn't mean they aren't out there.
I do know you are supposed to replace an EFB with an equal or better EFB.
If an EFB is not available than an AGM will work but anything else will not last very long.
I'll not get into brand names as that will result in this thread extending to infinity.

 

What we are finding is that vehicle that have "stop start" feature should start investing in a high-quality top brand battery. As your vehicle is aging now (sorry facts of life) the electrical demand is starting to slowly increase. So if you "cheap out" you are going to likely have issues. Not just with the battery failing prematurely.

We are now replacing as of last month a battery every other day in the shop. And with newer just out of warranty vehicle other parts now partially caused by a low-quality battery. It is no longer about what the specification are (but they are important to know) but more so who the manufacture is of the battery.

Sorry I can't give a battery brand or type recommendation other than what I posted because I do not know everything about your specific Mazda pertaining to its complete overall condition and complete health status of your electrical system.

On a side note, getting 5 years from your battery is extremely rare for your year and model are you sure about that fact?

 

I am at 30mths on our original battery and am wondering how long it will last.

 

Depends on what you are willing to do to maintain the health of the battery. Even in the best conditions without a trickle charger frequently used to maintain 13-13.5 volts constant all automotive battery will start a slow decline. Also, without the consideration to add larger or a few more batter cables the factory MAZDA cables are not the best size in the long term.
I would at least add a couple or more grounds and addition large single cable from the battery to the starter. The starter has the greatest load effect and naturally some of us it several times a day.


If not willing to do these suggestions, then.... by using the same battery load tester (load tester that show test voltage before, during and after in at least the tenth scale better 100 scale) and the exact same setting, make sure to get the temperature of the engine compart and better the battery at the time of the teat, log the results, repeat every 2 months and you WILL see if the battery is starting to decline.

 

My new 2022 OEM battery lasted just under 1 year.

 

yes it is the original battery from 2018.