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.

As far as I know, one battery! And yes you may need to reset the clock so to speak but nothing that requires the dealer attention..

As Ian says, one battery... Have a look at the THREE number code (Big numbers) and either match it or obtain a slightly higher CCA (Cold Cranking Ampage) rated one...

Leaving the battery disconnected for periods above 30-40 mins may have the effect of resetting the ECU, which in most cast cases, is a good thing as it will adapt to your driving from fresh!

Cheers Guys. I really appreciate your input. I have found two batteries on the internet on relevant sites. One at £200 and another at £100. Both are known brands and the only difference is one has a four year guarantee where as the other has 5. I know which one I'll be buying.

100 quid one sounds fine!

Yeah 100 quidder one lol... But they are retailing at 80something !!

Local AutoElectrician will get you one cheaper ;)