My battery ran down. I charged it back up and now it will not start. Why?

Hello, Your vehicle is sensitive to the battery charge. If it detects the cranking amps are a little low or the voltage is slightly low, that's enough. BMW is pretty well known for this. After sitting for a month, have the battery tested and slow charged by an auto parts store. Also, I've seen them fail to start with batteries that test good as well.

If the battery goes dead or is disconnected to install a new battery,then the vehicles computer system must be reset, contact your service specialist. see owners manual.