The battery in my new 2010 Mazda 5 was "weak" after only 2 years - replaced under warranty.
Now 2 years later this battery is also showing "weak" on load tests (9.5volts) while cranking.
Charging system is fine (14.5V).
Suggestions/advice wanted on why the batteries are not holding the full charge after only 2 years.

 

I have a few thoughts.
Short trips are hard on a battery.
Aftermarket stuff attached?
You must wrap your battery in insulation for it to last: it keeps the engine heat off of the battery (which helps kills batteries) AND it keeps the real cold off it so you can crank it.
A good read with same stuff: https://www.mazdaforum.com/forum/maz...tteries-27572/

 

Nope - short trips not an issue.
Nope - no aftermarket stuff
Re: wrapping the battery; friends' batteries all last ~6+ years (here in Ottawa, Ontario)
Thanks. I was wondering if Mazda (5s) have a history of poor original batteries...

 

Re: that other post linked to "...6 eats batteries"; good point about location of the battery. On my 5, it's in the left rear of the engine compartment while on most (?) cars I see, it's in a front corner where there's more airflow. It sure does get hot (back) there in the summer. If so, then all 5 owners would report short battery life, no?

 

I cannot stress how important wrapping your battery is,
DO IT.

Get the same battery i got from Canadian Tire: THE AGM https://www.mazdaforum.com/forum/maz...s-27572/page5/ post 41

The computer does control voltage! OH OH not HO HO!

READ: http://corporate.interstatebatteries...lls_batteries/ : article about heat and batteries from Interstate

 

I have a 2007 Mazda 5 and had to replace the battery for the first time last year. So two years twice in four years doesn't sound normal to me. Maybe the alternator is weak as well?

 

if i get 2 years out of a generic $50 dollars battery, im happy. but the weather here in Puerto Rico is pretty much the same all year around. 74 winter/95 summer. however, i think the worst for a battery is a hot alternator. if the voltage regulator is sending more than 15 volts, it will shorten the battery life and you will see a lot of corrosion on the battery terminals. again. cold weather is something i dont have to deal with but a hot alternator happens. connect a volt meter on the battery terminals and rev the engine to 2000 rpm. tell us what voltage you get. if i had to pay 150 dollars for a battery, then i would expect about 4 years. i usually get 4 years from my cheapo batteries. going to sears after a couple of years and paying about 90 dollars for a warranty after their computations are done... no. i keep buying the cheappos. tip. dont buy a battery based on the car info you give the battery seller, they will try to sell you the expensive one.. buy it based on the cca your car needs. that info is in the car owner manual, example:¨give me a battery with 700 cca and the positive terminal on the left side. what car do you have? a bicycle. just give me what im asking for, please. you can keep your warranty.¨

 

FrankB5, do you always lock your car when your not using it? Ie when your asleep?

 

Is the thinking that a locked car drains the battery more than an unlocked one?

 

Absolutely.
Some modules don't fully power down into sleep mode unless the car is actually locked. Its not a huge drain but does, very slowly drain the battery & reduces its lifespan and charge capacity over time.
Very big problem with sky-active vehicles that require a minimum of 75% charge to enable I-stop.