But with a 480AH bank and only using 80AH/day, if he's got a 25A charger hooked up constantly, he's almost certainly going to be running off of the top 5% of capacity anyway unless he's got something strange happening. Even if that entire 80AH is being consumed in a six hour period, that's still less than a 14A draw. I once had a refrigeration system that had a massive electric motor on it that drew about 30A when on. It didn't stay on all that long, but when it was, it drew 30A. If he's got something like that, a larger charger would certainly be called for.