when is the right time to change battery

[Txlee]

it's just all relying on how much electric the car need for its equipments, if yr car has been modified to have some more electricals, e.g. new Hi-Fi system, new headlight or even foglight ......... these may affect the life of the battery ...

Usually, I'll change the battery after 2 years, cuz you know it's quite anxious/ embrassment to get the car restart when your car is running out of battery in the road.

[motordavid]

Good conventional wisdom is to get your new batt., put it on a slow
trickle charge for a few days to fully top it up, and then swap it out
when convenient for you; not when it goes toes up and leaves you
stranded.

Many brands are available. It's an easy DIY. Be sure the vent tube
is removed from old batt. and reinstalled on new batt.

Here's a thread from my swap out on our 6yr old oem batt.

http://www.xoutpost.com/x5-e53-forum/...apped-out.html

Hit the Search Tab and you will find a plethora of threads on the topic.
GL,mD

[Purejoy]

On my previous 3.0i 2003 battery died w/o any real warnings some weeks ago. I needed to tow car to dealer (good that I paid extended BMW roadside service - free tow). Even the strong original battery it does not really give any warnings before it dies. We were sitting on school car line when worst happend - X5 is pretty heavy car to push and stear w/o power. If you have any indications of weak battery, change it sooner than later. Dealer took $250+ to put original battery in.

[zerochief]

Originally Posted by ealzar

so where did you guys get the battery, brandname and cost?

Sears, $120, replaced at 60K/4 yrs old.