This morning on the way to work my battery light came on, I noticed my dash lights dimming, and the voltage read out on my system dropped from its usual 14.1-4 down to 11.2.

I switched everything off that I could, and it stayed around 11. Eventually it went back up to 14 again, only to drop again, it kept doing this at random intervals at all RPM and made no difference what I had switched on.

Is this the alternator going bad? or the battery? Anything else I should check?

Thanks.

Took it to Autozone, tested out that the battery is the problem, replaced battery, fingers crossed.