That might be. I over-built mine to the point where I wouldn't have to worry so much and over voltage is like the #1 surest way to ruin any battery. I was not that confident in any sort of automotive type regulator to be 100% 100% of the time. Will it charge a little hotter on a hot day? A cold day? Under load? At high RPM spikes? Do keep us posted on this one, not like these cells are prone to explosion or leakage or catastrophic failure so you risk only the cost of the cells and honestly you can probably grossly abuse them and still get more life out of them than any AGM.