Battery light flashing not alternator issue

[Jaks101]

Initially I suspected that the alternator had gone because when you switch several electrical items on at once causing a lot of drain on the battery the light would come on.

The readings from the alternator when at the garage were all fine.
What else could my problem be. The mechanic suggested that he thinks it might be the ECU.
There are no error warning lights on in the car apart from the battery light occasionally when idling. It does not do it when the engine is under load though.

Any further ideas because I don't really want to take it to mini garage to pay a fortune to have it diagnosed.

[Cooper S Jon]

yes it is an alternator issue,put a voltmeter across the battery terms with the engine idling and report back with voltage.turn everything off that is possible..

[The Nun]

The battery charge light should not be going on and off when the cars idling normally, if it is either the belts are slipping or the brushes could be worn out or a loose connection.