How Long Does It Take To Charge A Car Battery At 4 Amps?

Charging car batteries at 4 amps.

It is an important thing to know how long a car battery go full uses a battery charger when you are away on a long road trip. I have tried different battery chargers specifically at 40 amps and 50 amps charging level.

However, a friend who is a mechanic once brought up, “What if you only have a 4 amps battery charger?” The main question will be, “How long to charge a car battery at 4 amps?”

So I researched quickly because that might happen to me while driving within a different continent. That’s why I need to be prepared. Since there are chances that I will be traveling abroad and there’s a possibility that there’s no available battery charger that can go up to 50 amps, I decided to try using the four amps to charge a car battery.

And this is what I found out: the lower your amp level on the battery charger, the slower it can get fully loaded. That is the rule. Since you also need to follow the same formula of getting the amp hours, you need to see the car battery’s reserve capacity value and then multiply it by 0.6. Once you get it, which is the charging time of the battery.

Charging A Car Battery At 4 Amps

A standard car battery normally can hold a 48 to 50 amps energy level. So if these cells in a battery charges at approx. 1 amp per hour it will still depend on how a car battery charger can give the desired energy level.

Commonly, a four amps charger can get a full charge from a flat dead battery until 12 to 24 hours. That’s quite a long time. So if you are expecting to use your car right away while you are in the middle of a long trip, then it is impossible.

I would advise that you recharge the battery during the afternoon while you are checked in a hotel room comfortably eating or sleeping so that you won’t be bothered. You’re relaxed, and your car battery is being recharged in a safe auto shop near the place.

Using a 4 amp battery charger for a car battery is not really fitting, and most shop won’t use this unless there’s no available higher amp charger. A 4 amp battery charger fits only for smaller batteries, like for motorbikes and other smaller ones.

What Is A Smart Charger?

A smart charger can keep your car battery energy level maintained. Just like a trickle charger, a smart battery charger has an automated feature of detecting whether the car battery reached its maximum capacity level of energy or if it’s already flat dead.

This automated feature enables the charger to turn off, if the car battery is already full – and turn on, once the car battery is already dead. It is a good thing to have this kind of charger because there will be no worries that it will overcharge in a matter of hours since it goes on and off by itself.

The only thing that could worry you is if the battery is in an area where dirt and corrosion might build up. Corrosion help creates problems on the battery terminals and may lead to a more serious problem that might affect the vehicle’s engine and the car itself in the long run.


It is essential to know how long does it take to charge a car battery at 4 amps because you may never know if you’re on a long road trip and the car auto shop that you have stopped by doesn’t have the other chargers that can produce 50amps.

You need to anticipate the worst and prepared for it. On this study, we have found out that it usually takes at least 12 hours to charge a flat dead car battery using a 4 amp battery charger.

Also, you can use a smart battery charger. A smart battery charger is like a trickle charger where it has an automated feature that it goes off when the battery is already full and goes on when it needs to be recharged.

Using this type of charger, you won’t worry about leaving the car battery charging over long periods. You have to worry about the dirt and corrosion build-up on the car battery casing due to its environment.

As a car owner, we need to make sure that these battery chargers are always on our car trunk at all times, or we know who to call in case of emergency.

We advise every car owner to study more about their cars and their car batteries to save time and effort of going into auto shops when you can fix your car battery problems at home. Not that you keep your time, the mechanic’s time, but also your money.