Morning Guys. Would anyone know how many batteries the 2005 520 diesel has? My wife tells me a symbol comes on the dash on cold mornings which she 'thinks' is battery related. I have noticed that the time and date needs re-inputting on the odd occasion and that lead me to think the battery is on the way out. My local garage (which isn't bmw) told me that it may have 2 on board batteries. That sounds odd as I have never heard of it before? Also,when you replace the battery do you have to re-programme the on board computer to 'tell it' there is a new power supply? Many thanks for any help.regards,steve.