My battery died and I suspect the alternator. To test I need to get the car running again and so borrowed a wall socket charger.

I have no idea how long I need to let the battery charge for.

Would anyone know how long I need to wait?

  • What is the amp/hour rating of the charger and the battery? – Old_Fossil Jul 9 '16 at 6:00

How long does it take to charge a battery? Ideally assuming 100% percent efficiency a 10 A battery charger would charge a 50 A/h (Ampere/hour) battery in about 5 hours.

Hours of charge = Ampere-Hour rating/charge rate ....ideally

In reality due the fact that when a battery is charging the charge rate is not constant. As a battery over time becomes charged the charging rate decreases. In reality it ends up being about twice the ideal calculated value.

Using the values used in the example above...10 hours would be expected.


If the battery is okay, you might need an hour to make it turn the starter and start a car. The rest should be done by alternator IF IT WORKS.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.