When Do You Need A Battery Recharge?

Here are a few signs indicating it’s time to recharge your car battery:

1. The Battery Is Dead

If the car doesn’t start, your battery may be dead and needs recharging. A dead battery essentially indicates that its voltage is below its functional battery capacity. 

For a car, the charge voltage is around 12.6 volts — that’s about the total voltage of 8 AAA batteries (1.5 volts each).

Why does this happen?

Car batteries can die when:

• The headlights are left on for too long
• The battery has a charging system failure
• A battery terminal is corroded (common in lead acid batteries)
• The car has been inactive for quite some time
• It loses power because of cold weather conditions

Note: If your car battery dies frequently, you probably need a battery replacement.

2. Broken Alternator

Alternators are responsible for replenishing the battery power while the car is running.

So, if you have a broken alternator, your car will have no way of automatically recharging the battery.

In this case, your car battery will need a manual recharge at the very least. But more immediate would be getting that alternator fixed. A broken alternator can overcharge the battery and reduce its lifespan.

3. The Check Engine Light Is Flashing

Many things can trigger a lit check engine warning light. But sometimes, it can just mean that you need to recharge your battery. 

What should you do?

If you don’t notice any performance loss (or other symptoms like strange noises), you could drive around to replenish battery power. And if the dashboard light switches off, then well and good. But if it doesn’t, you should take your car to a repair shop. 

A professional mechanic will test the battery and diagnose the root issue behind the warning light.

4. The Car Has Been Idle

The battery can drain if the car hasn’t been active for a long time. Most healthy car batteries can last for at least two weeks without use but will discharge beyond that.

If the car doesn’t start because it has been idle, you’ll need professional help as the battery could have corrosion or other issues.

But if all is fine, you just need to recharge the battery to get the car running again.

Note: A lead acid battery has a faster self discharge rate than a lithium ion or AGM battery. So, it will drain faster when idle.

5. Electrical Issues

Electrical malfunctions indicate battery problems. They can happen even when the car starts and runs fine.

So, if your car’s air conditioning suddenly turns off or the headlights go dim, your battery may need recharging.
Note: Recharging your car battery in any of the above scenarios is not a surefire fix for battery issues. For a comprehensive solution, seek professional help or replace the battery.

How Urgent Is A Battery Recharge?

The battery provides the power for the car to start. So, your car won’t turn on if the battery is dead. That’s why it’s best to charge the battery as soon as possible in case you need to use the car in an emergency.

You should also get the battery tested to see if it has any other issues that could harm the battery life span.

How Much Does It Cost To Charge A Car Battery?

An auto repair shop may charge between $10-$20 to charge your battery. 

But if the battery is faulty, you’ll need to buy a new one and replace the bad battery. Generally, a repair shop may charge a half hour to one hour of labor to install a common car battery (standard lead acid batteries) as it’s simpler and faster.

4 FAQs On Battery Recharge

Here are four frequent queries about recharging car batteries:

1. What Is A Battery Recharge?

A battery recharge is the replenishing of a discharged battery with electrical energy. It involves the movement of electrons from an external power supply to the battery’s anode and cathode. 

But for cars, this isn’t as simple as charging a rechargeable AA battery or AAA battery with an AA or AAA battery charger.

How does this happen for a car?
Typically, the alternator recharges the battery while the car is running. It turns mechanical energy from the car’s crankshaft into electrical energy — charging the car battery.

But an alternator can’t recharge a battery without a running car. So, if the car can’t start, you’ll need to find alternative solutions, like a charger or portable car battery pack, to get the battery recharged.

2. How Do You Recharge A Car Battery?

Here’s what you can do to recharge a dead car battery:

1. Jump-Start Your Car

Jump-start the car using a jumper cable and a healthy battery from another car (or portable car battery pack), then recharge your battery by driving around. Keep the engine running for some time (at least 30 minutes), as the alternator needs time to recharge the battery.

2. Use A Car Battery Charger

Before connecting your car battery to a charger, you need to test the battery voltage and check each battery terminal for corrosion. 

Then hook up the rechargeable battery to a charger with a charging cable, and charge. You can do this while the battery is in the car or even if it’s disconnected and removed. 

Make sure to maintain necessary safety precautions while using a car battery charger.

Note: A lead acid battery, NiMH battery, lithium ion battery (li-ion), or any other type of battery may have a distinct charge current or constant voltage specification. So, check the manufacturer’s manual to find the best way to recharge the battery.

3. Can I Recharge A Completely Dead Battery?

Yes, it’s possible to recharge a dead car battery — provided that it’s only discharged and doesn’t have other issues like battery swelling or leaking. 

Moreover, recharging is an easy fix, whether you do it yourself or seek remote assistance from a car mechanic. But if the battery is still under warranty, you may want to consider getting it replaced.

4. How Long Does It Take To Charge A Dead Battery?

A flat car battery can take around 10 to 24 hours to charge fully. But this battery charging time depends on the battery type and mode of charging.Here are a few interesting case studies for different battery types:

• It takes 12 hours to recharge a 48,000 mAh (48 amp) car battery using a 12 volt battery charger.
• Lead acid batteries take an average of between 12 to 16 hours to recharge. In fact, a lead acid flooded battery charges 5 times slower than an AGM battery.
• It can take around 8 hours to recharge a 60kWh electric car battery (lithium ion) using a 7kW battery charging point. But in general, a lithium battery takes between 30 minutes to 10 hours, while a NiMH battery takes between 1 to 6 hours for a full charge, depending on the power supply.
• It can take up to 48 hours to trickle charge and replenish a car’s battery capacity, depending on the type of trickle charger.

Additionally, the charge time can increase if you use the car’s electrical devices, like the dashboard LCD display, while recharging the battery. So, you may want to keep all vehicle electrical components shut off.

Finally, fast charging may harm your car’s battery in the long run. So, it’s best to recharge batteries slowly or with a smart battery charger to preserve battery life.