Actually, if I were to be a Pollyanna', I think the correct equation would be:
For every 130W of panels, you'll need
130W/28.8V = 4.5A
4.5A of MPPT output per 130W of panels is
... I haven't a clue ... so a 15A will probably work over 400W, I guess.
(what's a mppt... :unsure: )
I am...