[Kafer]

I'm having issues with my battery being able to hold a charge and am looking into getting a charger / tender while BMW figures out whether they will replace the battery or not.

Can anyone tell me the difference between the CTEK 3300 Battery Charger (http://smartercharger.com/battery-chargers) and the BMW Advanced Charging system? Any suggestions on which to use?

Thanks!

[fdriller9]

Not sure what the difference is but I wouldn't tell the dealer you are using a tender. If you get the wrong one, you may do more harm than good.

What makes you think your battery isn't holding a charge? How did you test it?

Are you sure there isn't something in the car draining the battery? Someone had a problem where the trunk latch was drawing power when the car was off and was draining the battery.

[Kafer]

Here is the thread with my original problem: http://www.e90post.com/forums/showth...hlight=battery

I've been in twice to have it checked out and they determined that nothing is drawing power when the car is off, so I'm assuming the battery is defective and unable to hold a charge. The last step they took is to clean the connections (even though the car is less than a year old) and charge it up again. I'm not sure what it will take to get them to just replace the battery.

In any case, I can pickup the CTEK charger for $50 which would temporarily keep my going until I can sort things out with BMW. Just want to be sure that it's a good option or not...

[raj55]

The C-tek battery charger 3600 model is exactly the same as BMW's own battery charger. Scroll down this site and check.

http://www.schmiedmann.se/3_serien/e...da6.htm#paging

[Tj Hunter]

A battery charger is only as good as the person using it, if you charge the battery incorrectly there COULD be damage, but if you are competent in using a battery charger it does not matter what brand you use.

[FlyingKid]

Just went through the same problem. I also had to get a tender...

Fist dealer thought that my rear defrost problem I went in with had to do with its controller not working properly. No knowing any better, they ordered a "controller" and I had to waste another day going back for them to change it. They took half a day to apparently reprogram my car but I think they were just recharging the battery.

A second dealer (recently moved...) mentioned to me when I went in with the same rear defrost problem that it had to do with the battery charge level and not the rear defrost controller. Turns out that when the battery gets too low, the master controller/computer will shed some of its systems to preserve the remaining charge in the battery.

I also think my battery is defective or something is draining it. That second dealer told me that the trip I just took a couple of days earlier would not have recharged the battery even if I drove for 8 hours straight (mostly highway but also thru towns). He said that it is possible that my battery will not recharge enough as it only recharges when the car decelerates?! Understand the principle but I don't drive an F1 with KERS!? I do everyday driving in cold winter weather. My car does sit in my non-heated garage at home for some time as I travel a lot but I have never had this kind of problem before...

Put it on charge a few weeks ago now and just returning home today so we'll see how it does when I use it in normal everyday driving for the next couple of weeks...

Forgot to mention that I got the BMW battery tender and it seems to work just fine. Was around $70 CDN.