You have either 10 or 13 groups of cells in series inside your battery. The working voltage of these cells is between 3.0 to 4.3Volts. Nominal volrage, at half charge, is around 3.6V. So multipl the nominal by 10 or 13, and you get 36 and 48 volts.
Your battery shuts off when any group hits 3.0 volts, so it's the lowest charged grourp that determines how long you can run your battery. For recharge, your charger shuts off when any group reached 4.2V, so it's the highest charge group that determines how long you can charge the battery.
When a battery is badly out of balance, like lowest group at 3.6V and highest at 4.2V, you van only get half the use out of the battery, and you cannot charge up the low group either because the charger shuts off too early. If you battery can balance itself, it will do so during a long charge. The charger may show green, but the battery will try to discharge the higher groups and let the lower groups catch up. That's why they suggest those three long charge cycles.
Some batteries don't balance. Those that do will take a long time. It might take a week if you really had cells that were 1/2 volt apart. Usually, the cells in a new, healthy battery are within .10 volt of each other.
