Better wire for solar panels -> charge controller?

[Bear in NM]

No, I was referring to the fact that both the Duo and the 1215a are made to charge two separate batteries/banks.

Both are perfect for an RV as they can not only charge the house battery, but can keep the engine cranking battery topped up as well.

Gotcha. And the charger will actually do 3 battery banks. This should allow me to charge my starter, aux and suitcase batteries at one time. Like during the winter, when it's 20 degrees blowing snow, and I am feeling guilty about topping everything off ;^)

Craig