PlayStation 3 brand new
I have the exact same issue (different PS3, slim 300GB) same charger, slow blinking red lights when plugged in - genuine PS3 controller (red). My black one that came with the system doesn't have a problem. Did you find solution? I cannot find an anwer anywhere on the internet even couldn't find a person besides you that has this same specific problem.
I've reset, resynced it, let it sit in the cradle charging forever - also btw it still blinks like that when plugged into the ps3 directly so it shouldn't be a charging stand issue.
The only difference is that I've had this red controller for almost 2 years now. Possibly the battery is going out? So one question - how long does the battery charge last on the blinking 4 red light controller? I'm about to test mine.