2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
can I connect 3 sets of 4 38.8 volt panels in series in parallel on a mppt t60-150 charge controller
From the description given it sounds like a Schneider Conext 60-150 charge controller . If they have a string sizing tool I couldn't find it. Their site is not easy to navigate.