Charging Time (in hours) = (Battery Capacity in Amp-hours) / Charging Current (in amps)
Assuming the battery has a capacity of 100 amp-hours, the charging time would be:
Charging Time = 100 Ah / 1.5 A = 66.67 hours
Therefore, it would take approximately 66.67 hours or 2.78 days to charge a 12-volt, 100 amp-hour battery at a constant current of 1.5 amps.
It's important to note that this calculation assumes an ideal scenario and does not account for factors such as inefficiencies in the charging process or self-discharge of the battery. In practice, the actual charging time may be slightly longer. Additionally, it's recommended to follow the manufacturer's guidelines and use an appropriate charger to ensure safe and efficient charging of the battery.