Question

A 12 V battery is rated for 48 AH. If it must deliver an average of 2A, how long will the battery last before it needs recharging.
1. 48 hours
2. 4 hours
3. 2 hours
4. 24 hours

Answer 1

Correct Answer - Option 4 : 24 hours

Concept:

• An Amp Hour (Ah) is the amount of current a certain battery can supply for a certain period of time.
• If we have the amp hour rating of the battery, we can compute how long the battery will last while supplying a certain current. 
• The ampere-hour rating of a battery is given by multiplying the current (amperes) by the discharge time (hours).

​Calculation:

Given:

Current = 2 A, rating of battery = 48 AH

\(Discharge ~time =\frac{Ampere ~hours}{Current}\)

= \(\frac{48}{2}= 24~ hrs\)