If your battery comprises of 3 cells…. follow below caluculation….
6v 5Ah Lead Sulphuric Acid Batteries
Nominal Capacity 77oF(25oC)
20 hour rate (0.25A, 5.25V) 5Ah
10 hour rate (0.47A, 5.25V) 4.7Ah
5 hour rate (0.78A, 5.25V) 3.9Ah
1 hour rate (3.2A, 4.8V) 3.2Ah
6v 4.5Ah Lead Sul
Nominal Capacity 77oF(25oC)
20 hours rate(0.225A 5.25V)4.5Ah
10 hours rate(0.43A 5.25V)4.3Ah
5 hours rate(0.78A 5.25V)3.9Ah
1 hour rate(2.8A 4.8V) 2.8Ah
You Might Find the help from schematic given below