Not correct. If you're above the gassing voltage, then current will never drop to zero. Voltage, current and temperature all interact, to determine when battery is full.
But bottom line, who cares if they're full? Use them, abuse them and then get new ones. I get about 500 camping days out of two GC2s. That's good enough for me with minimal battery attention. They're one of the cheapest items in my MH.
pnichols wrote:
With any kind of charger (solar, converter, etc.), whenever the ammeter reads zero with charging voltage applied to them it means that the batteries have been fully charged.