Solar Systems

[Nix]

ie your original intention of a 20W panel would, at best on a good day, only be trickle charging your battery/ies at approx 1.6A so not a great deal of power going in to your set up. On a bad day, forget it, it'll be negligable. 5A controller would take a max of 60W and no more so you might just squeeze another two of those 20W panels but it'll be at maximum capacity which is never good.

With an 80W panel, you've got well over 6A on a good day, four times the amount. Also, you can add another 80W panel, no problem = 160W or 12A so not stressing out the 20A controller.

Think of it this way, you're burning a poxy 20W bulb or four times the amount (80W bulb) on a good bright day with the energy coming in.

Big difference, aye?