Effects of Sulfating
During discharge, lead can dissolve and form into hard crystals on the battery plates, impeding electrical flow and performance. Fully recharging returns most sulfates back to solution. But here's the rub: Batteries, especially flooded cells, are often not fully recharged since, as a battery reaches full charge, its resistance increases, decreasing the "charge acceptance rate." The battery refuses to accept more juice. Current from an almost-charged battery is often not enough to prevent the sulfates from crystallizing, especially deep inside the battery on the inner plates — except in gel and AGM batteries, which are made to combat that effect. But there is a solution, with high-tech chargers offering de-sulfating features as described above.