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Discussion Starter · #1 ·
I've had my 330i since August of 2017 and still have the original battery. I'm pretty impressed because I only get 3 years out of batteries in my Japanese cars. How long do these BMW batteries last in your experience? BTW, I don't use the auto stop-start function.
 

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Newer BMW's have absorbent glass mat (AGM) batteries. They seem to hold up better than conventional arteries. The AGM in my 2014 535i lasted 6.5 years. Then, it got weak a d caused my sunroof control hardware/software to lock up.

I keep cars ten to twelve years. So, I'm going to start replacing AGM's at six years.
 

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Original batteries in my X3 and 340i (both with Fall 2017 in-service dates). No electrical issues yet, but I'll plan to get a new battery for the 340i this year due to shorter commute and higher mileage.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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My AGM is past six years, seven years in spring.

The apparent advantage of AGM is due to the coincident improvements in the batteries’ environment. The enemies of battery life are heat, dirt and vibration.

An actual advantage is their fragility to too high charging voltage / current, due to their limited electrolyte volume that cannot be replenished. Excess gassing is a function of temperature and voltage. To avoid this fragility requires the AGM be gently used.

AGM battery service life is correlated with the Average State of Charge, with average SoC = 70% implies 1,000 equivalent cycles of full rated discharge and recharge.
 

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Discussion Starter · #5 ·
Newer BMW's have absorbent glass mat (AGM) batteries. They seem to hold up better than conventional arteries. The AGM in my 2014 535i lasted 6.5 years. Then, it got weak a d caused my sunroof control hardware/software to lock up.

I keep cars ten to twelve years. So, I'm going to start replacing AGM's at six years.
Not bad. Are these batteries difficult to replace as a DIY project? Any special equipment required?
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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AGM have a vent pipe (their full name is Valve Regulated Lead Acid Absorbed Glass Mat) to vent excess gas pressure out of the cabin. So there needs to be a new hole in your car. Beyond that the physical change is straight forward. BUT the charging system must be properly (re)programmed for battery type and charging protocol and limit.
 

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2015 BMW 535i
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BUT the charging system must be properly (re)programmed for battery type and charging protocol and limit.
Easiest when you replace "in kind" with the exact same spec'd battery. Then you'll only need to register it.
If you change the Ah rating, then you'll need to code it as well. Both processes are fairly simple and straighforward, just need proper scan tool / software / app.

Me: 2015 535i (F10) w/ original H9 105 Ah Battery (~ 8 years).

I'm surprised with its longevity. Will be replaced soon for PM.
 

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My 2014 328 Xi GT when till 2022, 8 yrs. It was still working and I would put it on the C-TEC every so often but this is Minnesota so I replaced it with same type.
 

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One of the best automotive purchases you can make is a good quality battery charger. Newer chargers work with both conventional flooded lead acid batteries and AGM batteries. Charge your battery on a monthly basis and you will maximize its life.
 

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One of the best automotive purchases you can make is a good quality battery charger. Newer chargers work with both conventional flooded lead acid batteries and AGM batteries. Charge your battery on a monthly basis and you will maximize its life.
I'm with you Crazy! I do my battery every two months or so with the unit, whose name escapes at the moment, that does an 8 step process to recondition it as well as charge it. One of my Bimmers is 5 years old and the other is 4 years. So far so good! 👍
 

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I'm with you Crazy! I do my battery every two months or so with the unit, whose name escapes at the moment, that does an 8 step process to recondition it as well as charge it. One of my Bimmers is 5 years old and the other is 4 years. So far so good! 👍
CTEK & Noco offer some good products.
 

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My battery is 3 months short of 10 years old. Will I hit 11.0 years? I want to change the battery in May 2024.
 

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I just replaced the battery that came with my '14 F32 because it was discharging... Very impressed by the longevity overall ! I ended up paying $240 for a perfect replacement that included installation and registration-great deal I believe.
 
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