How Long To Charge A Dead Car Battery With Alternator. The most common rate for car battery chargers is around 4 amps. It means that a high capacity charger would merely take 4-5 minutes to fill the battery.
If the battery is deeply discharged 15-30 minutes on a 40-amp charger will provide charge and give the alternator a chance to finish charging the battery while driving your car. At idle the battery can take around 2 hours to charge up to 80 complete if it was flat and the alternator can generate. But remember you dont need to charge the battery all the way up.
On the other hand if the charging is tickling it may take around 24 hours to charge a dead battery completely.
Which of course in real life the. Keeping a car battery plugged in for twenty four hours can fully recharge your battery and chargers are typically quite affordable. 40 amps has a fast-charging capacity and can charge a cars battery within a few minutes to an hour. For the health of your battery and car replace the alternator as soon as possible once it has failed.
