Cheap way to isolate and charge gel cell- relay or diode ?

Some people say that Optima said their AGMs were gels.

I don't recall ever seeing that on the Optima web site as far back as 2009. I bought my first, and only, Optima Yellow-Top with light gray case in Jan 2010. Today, it is starting my 6.0L V8 gas engine in my 2004 GMC Savana. It has 750CCA in a 43.5lb package. It will still kick a 53lb FLA out the back door. :)

HTH;
John