battery ques

[JIM1inWisconsin]

I had a new one installed about six months ago and I don't believe my mechanic updated the ecu or as they say registered the new battery. Seems I'm getting weak starts and suspect the battery. What should I do at this point?

[dtla1]

Take it back and get it recoded. But also check to see if you can pull any codes. I know that on turbo cars (135i), slow starts might also indicate a failing HPFP.

[JimD]

Old batteries require more charging than newer ones. But smaller ones need less than larger ones. If you replaced with the same size, I see no reason the lack of coding would contribute to slow starts. If you replaced with a higher amp hour battery then it could contribute to slow starts.

Over or under charging will not lengthen the life of the battery but you cannot do anything about that. The solution is to check the coding and, if necessary, fix it. Cheapest route seems to be to buy the cable and download the software from Bimmergeeks. The software will not be real user friendly but it is very capable. You tell the car the batteries age in INPA and you will need to find the module with the setting for the battery size using NCSExpert.

[JIM1inWisconsin]

Thanks Jim D. Certainly is getting a bit complex.

[gjm120]

Originally Posted by JIM1inWisconsin

Thanks Jim D. Certainly is getting a bit complex.

To complicate it a bit more - once you know if the car is coded to the right Ah and type of battery (AGM or flooded cell), it's a ? as to whether you should register the battery or not. I've heard don't register and older battery but 6 months not sure what to think about that.

[Gangplank]

You can register the battery with the Carly app on either iPhone or Android.

https://www.1addicts.com/forums/show....php?t=1384864

[MightyMouseTech]

At only six months old, I would still register it ASAP. The dealer can see when it was last registered and confirm whether it was done or not.

[NorthernDancer]

Get yourself a quality battery charger/maintainer [Deltran, CTEK or Schumacher] and fully charge your battery over night. Then if you have same issues, then look for loose or dirty connections. A ground cable between chassis and engine block is very often the problem. Look thru posts here-I think the cable goes from starter to a body ground, right side of vehicle I think. And, yes, do get battery coded.

[desertman123]

May be worth going to an auto parts store and having them test starter/alternator/battery. Starters are known to be a weak point on this whole chassis lol.

[JIM1inWisconsin]

Thanks my indy, who I've used for years, tells me it's the starter and a new one will be installed Monday. Then again he was not aware that the battery he installed needed to be registered. Guess we are both getting a little long in the tooth.