Flat battery??

[Wayneoneeye]

Hi guys.u have a 1 series 118d msport  2013   ,when i take it on a good run ,say 20mile round trip,when i switch off,if i try to start straight after on the push button,it struggles to start ,the battery sounds flat , it wont start,i have to get my bartery booster to start it!  It starts fine when cold ...any help would be much appreciates   TIA

[Bimmer Owners Club]

Hi .... welcome to the Club

I would advise replacing the battery or at least having the battery monitoring system reset to learn the new voltage once it has been fully charged

[Wayneoneeye]

Ive had the battery tested and says its fine, battery monitering system reset ...?  How do you do that sorry for being dumb 

[p38fln]

You can reset it with Carly or Carista (Smartphone apps, requires additional hardware sold separately) or have a BMW technician do it.  There isn't a way to do it from the car itself.  How old is that battery?  If it's the original 2013 battery you are probably headed for a replacement pretty soon anyway.