Charging Time Required

The time required to charge a battery will vary depending upon the following factors:
A. Size of the Battery - A completely discharged heavy-duty battery requires more than twice the recharging time as a completely discharged light-duty battery.
B. Temperature - The colder the battery, the more time it takes to recharge. When a fast charger is connected to a cold battery, the current accepted by the battery will be very low at first. In time the battery will accept a higher rate as the battery warms.
C. Charger Capacity - The higher the charger amperage, the less time it will take to charge the battery.
D. 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, charging current will also increase.

Any battery discharged by parasitic current drain, and then allowed to stand in this condition for a period of time, may not accept a charge readily. However, if recharged long enough, many batteries will return to a usable condition.

If the battery remains in an extremely discharged condition for a prolonged period it can become permanently damaged. This damage can be accelerated by changes in temperatures. Batteries that are extremely discharged can freeze at temperatures as high as -7°C (20°F) and be permanently damaged.

To prevent battery damage and recharge problems, vehicles that are not going to be in service within a 30 day period should have the negative battery cable disconnected to remove the constant drain on the battery. If this is not possible, recharge the battery periodically every 30-45 days until the green dot is visible.