In all fairness to my Optimas, this thread had me investigate my connections and supply to my ARB fridge. While I had no voltage loss all the way to the socket, my non-locking socket needs to get swapped. slight movements in my ARB 12v plug will cause voltage loss, which explains why I've had the fridge red error light come on so quickly sometimes. I don't think I could go 4 days on my yellowtop 34 group, but I'll be solving that soon with a permanent solar setup. Those Optimas will still get replaced with Sears Diehard Platinums thought when it is time. If nothing else, they have more reserve cap.