E90 BMW 325 M Sports 2007' battery

[aroha]

When the car is not moving, the only thing that is utilizing your battery is the alarm system which is insignificant compared to the battery power drawn during cranking up the engine and alternator will take over from here on and charging the battery. That said, MOST if not all of the time battery is not utilized fully.
On your question of why it only lasted 2 years @ 100k KM, if you do your driving in city most of the time and less than 10KM, battery will undercharge, and to make it worse, more frequently cranked. Thus battery lifespan will decrease. If you did it mostly on highway for a long distance, battery should last longer.

Thanks for info IsaacVky.

That's the thing, it should last longer as i expected as i use it mostly on highways. 150km-ish on daily basis. But after reading your explanation, i think my battery drained so fast was due to i rarely switch off my headlamps when starting up the car. haishhh. i dont know man. but thanks!

 

[Schwepps]

Constant Current or Voltage charger?
You gotta know the difference bro. :love:

Good point, but don't frighten him la, IsaacVky!

Just ensure you're using a good quality automatic charger Porsche168, not an el cheapo manual one. Then you won't have to worry about overcharging. Also follow the instructions and safety rules.

 

[Schwepps]

That's the thing, it should last longer as i expected as i use it mostly on highways. 150km-ish on daily basis. But after reading your explanation, i think my battery drained so fast was due to i rarely switch off my headlamps when starting up the car. haishhh. i dont know man. but thanks!

It's safe to leave your headlights and aircond on Auto as they cut off when cranking the starter, so doubt that's the reason. If you're driving 150km on highways daily, everything about your car should be healthy, especially the battery. Maybe the original battery itself was bad, or your alternator isn't giving adequate charge. Anyway, you should try to change the battery and find/fix the cause under BSRI, although you've exceeded BSRI mileage limit. Take it in ASAP and get loud. :wink: