Charging Time Required

The time required to charge a battery will vary depending upon the following factors:

• Size of Battery - A completely discharged large heavy-duty battery requires more than twice the recharging time as a completely discharged small passenger car battery.
• Temperature - A longer time will be needed to charge any battery at -18 °C (0 °F) than at 27 °C (80 °F). When a fast charger is connected to a cold battery, the current accepted by the battery will be very low at first. The battery will accept a higher current rate as the battery warms.
• Charger Capacity - A charger which can supply only 5 A will require a much longer charging period than a charger that can supply 30 A or more.
• State-of-Charge - A completely discharged battery requires more than twice as much charge as a one-half charged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the current accepted by the battery is very low at first. Later, as the charging current causes the electrolyte acid content to increase, the charging current will likewise increase.