Maine Sail, I read your postings on Sailboat owners. com. I need 4D batteries and found this:
http://www.samsclub.com/sams/duracell-commercial-battery-group-size-4d/prod3590230.ip?navAction=
I called and did confirm that it is made by East Penn.
I am concerned that it might not be deep cycle. They list it as a "commercial service" battery.
Do you have any thoughts about it.
Thanks for the other posting.