A vehicle uses a lot of electricity to run the ignition and the electrical devices. If power comes from a battery, it would soon get depleted. So, a vehicle should have a rechargeable battery and a charging unit to keep it recharged.
How many minutes to recharge a dead car battery? The time taken to charge your car varies depending on how much charge the battery has before you start driving and the driving speed. If, for instance, you keep your engine RPM high, the alternator will charge your battery faster. If driving on a highway, the battery will take 30 minutes to charge, and if driving in the city, it will take an hour or more. At idle, the battery can take around 2 hours to charge up to 80% complete if it was flat, and the alternator can generate 14 volts.
Factors Affecting a Car Battery Charging Time
Several factors determine the time duration to recharge a dead car battery.
- Condition of the battery- a well-maintained battery having sulphuric acid and water takes less time to charge than a battery with issues.
- Battery size- a 12 volts battery may take less time than a 24 volts battery.
- The power of the charge – a high-capacity charger can take around 4-5 minutes to fill the battery. But if the charging is tickling, it may take even 24 hours to charge a completely dead battery.
- Engine RPM- when driving faster at a highway speed, the battery charges quickly, unlike when idling.
- Alternator size/ Output capabilities- an alternator generating more power and has less load will take less time to charge a battery than one producing insufficient power.
How Many Miles Do I have to Drive to Charge a Dead Car Battery?
As mentioned above, some factors determine how long or the miles you will take to charge a battery. Depending on your speed, the alternator’s output, the battery capacity, and more, it can take around 60 miles to charge your battery. But if you aren’t driving, there are other ways you can use to charge your battery;
Use a Battery Charger
Before charging, ensure you follow the safety tips like; wearing gloves and eye protection, ensure the charger is far away from the car, avoid touching clamps, etc.
- Choose a proper charge setting and rate your battery type.
- Take the charger cables and unwrap them, then locate the positive and negative terminals. For positive check for P, POS or the + Symbol, Negative, look for G, NEG, or – sign.
- Hook the red line to the positive end and the negative to the negative battery terminal.
- Connect to the power source; you may require an extension cord to reach the car. Wait for your battery to charge.
Use Another Car Battery/ Jump Start
This method for charging your battery uses jumper cables to connect the dead battery to a running one. Before charging, please make sure the two batteries are of the same nominal voltage rating to avoid damaging the vehicle’s electrical components (a 24V system will, for instance, damage a 12V system). The dead battery takes around 20 minutes, then drive for at least 30 minutes to have a reasonable charge.
- Turn off the ignition on both cars.
- Clamp the positive cable end to the dead battery positive clamp. Have your friend connect the other end of the line to the other battery’s positive clasp.
- Next, fasten the negative cable to the negative terminal of the charged battery. Later connect the other end of the negative line to the ground on the vehicle with the dead battery. Be careful the ends of the cable not to touch. The ground can be an engine block or any metal surface away from the battery.
- Start the rescue car and the car with the dead battery. If the vehicle with the dead battery fails, check your connections. So, how long before turning off a vehicle after jump start? Well, If the car starts, let the car run for like 20 minutes to allow the battery to recharge before turning it off.
How Long Does it take to Charge a Car Battery while Idling?
Will idling recharge a dead battery? Yes, your dead battery can charge while idling. The alternator does charge your battery when the engine is running, and the alternator is working fine. The engine turns the serpentine belt which turns the alternator for it to generate electricity for your battery.
Though the method is a solution for recharging the battery, it’s not advisable. An alternator is best suited to produce electricity at high RPM as opposed to what it gets with the engine idling, as its power reduces to a trickle of about 2-3 amps after 10-20 minutes; this means you require more hours to charge the battery when idling than just taking a drive.
Below is a calculation of the battery’s charging time ;
If a battery has a 100 AH battery and the applied current is 10 Amperes, then the charging time will be;
Capacity / efficiency = 100AH/10A= 10 hrs. Leaving a car running to charge the battery isn’t the best option; instead, consider taking a drive or even using a charger.
Check this too: How To Recondition A Car Battery That Won’t Hold Charge
Conclusion
To avoid being stranded with a discharged battery, always keep serving your battery. It’s also wise to drive your car regularly to allow the alternator to maintain your battery’s charge level. Again, follow the safety tips while charging your battery to ensure it serves you efficiently.