How long does it take to recharge a 70ah battery at 4 amps?

To calculate the time to recharge a 70Ah battery at 4 amps, you can use the formula: time (hours) = capacity (Ah) / charge current (A). In this case, it would take approximately 70Ah / 4A = 17.5 hours to fully recharge the battery, assuming 100% efficiency and that the battery is completely discharged. In reality, charging efficiency and battery condition may extend this time.