I think I get to learn the other side of the 'overkill' equation... before, I was running a small battery bank, and an overkill on the solar panels for that size bank.. frequently my batteries werent able to accept all that my controller could send them during the day.
well, since the new bank installation, I have yet to see the 'Float' light on the controller come on! they are getting a good charge, and pulling in the power at 14.4v, which is great, but they are taking all that it puts out.. when you look at the numbers, thats not suprising, but I never considered that. 8 batteries taking in 16amp at the end of the day is only 2 amps per battery, and with a charge of 2 amps coming in, it can take a long time before they will stop accepting that charge. Slow charge is great for them, so not worried about that, but sure have to change my expectations :)
At this point, my past power issues are gone.. I can kick on the pc and radio first thing in the morning, run all day and into the night if I choose, and never run low on power, in fact, I've not been able to drop them to even half at this point, and it should only get better as the sun continues to rise with the coming summer. A well spent 400$