Hey everyone. First time post so thank you for having me. Just wondering if anyone has any thoughts on an issue I having please.

My battery light is coming on for about 85% of my journeys, but not at the same time or for any obvious reason. And I cant make it happen, it just does it

I have tested non running battery voltage (12.6v on the last test, but have been up to 13v) and also running volts (which were 14v). Also tested fully running with air con, interior and exterior lights on and it read 11v (but I never run the car like this in general). I borrowed a charger to test fully charging the battery and it goes to a max 13v with being left to charge for 6.5 hours

Drove in the dark and the lights seem slightly less bright when the battery light is on, and a lot brighter when the battery light decides to disappear. But revving the car doesn't make the lights brighter...

I've been able to drive it in the day for the last week, approx. 100 miles in total, and tested the battery after which was at 12.6v... It also starts as normal on every start, doesn't struggle or anything

Is it now a case of getting it to a garage, or does anyone have any ideas please? 

Thank you for any help!

Sounds like the alternator is on its way out.

Seems like you have an issue with the alternator 'smart charge' control. A common problem is a broken or corroded wire/connector. Check and inspect very closely the plug on the side (sometimes back) of the alternator.

Disconnecting the smart charge plug should cause the alternator to start charging the battery at 13.95V which is the default in the event of smart charge failure.