I did some searching and they are made in Mexico and not the US anymore. But according to a Optima representative most of the returns come back discharged and after charging they are fine. I learned this a long time ago when I ran mine dead and the rigs converter would trip the DC breaker when trying to recharge them, I ended up charging one at a time. When dead they draw a high charging current and almost act like they are shorted.

I also learned to turn my batteries off when in storage so the trailers parasitic loads won't drain them.

Denny

 

Yeah, I've seen them make that claim too, but just too many people are still having issues even when following Optima's exact steps.
If what the reps claim were really the case, who owned the company and where they were made would make no difference in the failure rate.
It would have remained the same from when they were made in the US by Optima vs. made in Mexico by JCI.