Which ampere-hour battery can I charge?

Charge the car battery - this is how it works

If the engine "organizes" when starting, the battery weakens. In the worst case, only
one more “clack” can be heard and the car won't start anymore. What are the options for recharging the battery - the most important information.

Charging the starter battery by the alternator

Actually, the car battery runs off while driving generator (Alternator) charged,
without the driver having to worry about it. If the alternator does not manage this, however, it is due to the so-called charge balance. In plain language: If more is withdrawn from the battery than recharged over a longer period of time, the energy will decrease Energy content so far that the car won't start anymore.

This is especially true in winter for cars with many electrical consumers such as heated seats, air conditioning, heated exterior mirrors, heated rear windows, etc. To make matters worse, the battery at Freezing temperatures absorbs a poor charge and charging is slower accordingly.

Short distances are not always enough to get the Charge level maintain. There
it only helps to drive longer distances in one go or to charge the battery with a charger.

Charging the car battery with the charger

In order to be able to charge the battery in the garage at home, there is a socket and a matching charger required. Universal, fully automatic chargers with protection against spark formation, short circuits and polarity reversal are ideal. Integrated temperature compensation for low temperatures in winter is also recommended. Also for cars with
There are now optimized chargers for the start-stop function.

Important: You should definitely refer to the vehicle owner's manual for section
"Charging the battery" (here you will also find the specified charging points) and the instructions
of the charger.

By the way: Maintenance-free batteries are standard these days. The only thing the vehicle owner can and should do is charge it.

Jump start via external battery

If you got stuck on the way and a donor car is available, you can
Your vehicle by means of a Jump leads start. Then you should
recharge the battery by driving for a long time or charge it with a charger. Information on how to bypass the car and give or receive jump start help can be found here.

How can the state of charge of the car battery be determined?

Unfortunately, how “full” an (older) battery is cannot be determined by the Measurement of the open-circuit voltage determine. This only provides information about the state of charge of the battery:


State of charge

Result and ToDo

> 12,4

> 60 %

= ok

12,0 – 12,4

25 – 60 %

= should be loaded

< 12,0

< 25 %

= must be loaded

The one available Energy content - especially by older ones
Batteries - can only be determined by means of a complex residual capacity measurement. The following example illustrates why this is so:

A 5-liter water bucket and a 10-liter water bucket are the same height and have the same level as the Battery voltage corresponds to. The smaller bucket still contains less water because its capacity is smaller than the
Remaining battery capacity corresponds to.

How long does it take to charge a car battery?

That depends on the capacity of the battery and the maximum charging current of the charger
from. Usual maximum Charging currents are, depending on the retail price of the charger, 5.7 or 10 A. The larger the battery, the greater the charging current should be. For example, charging an empty 100 Ah battery with a 7 A charger to 80 percent takes up to eleven hours.

How long does a car battery last?

A car battery is one Wear part. How long it lasts depends on two things:

  • the quality of the battery itself

  • the individual terms of use

Experience shows that car batteries keep out of the Original equipment of the car longer than so-called after-market batteries. This is because the quality standards of the
Automobile manufacturers in terms of the newly installed batteries are usually higher than on the very price-sensitive ones Aftermarket.

The margin for that Cost of a new battery is very broad and dependent on her
Capacity, their technology and, in the end, their quality. For example, a good conventional 50 Ah lead-acid battery costs around 90 euros and a good 100 Ah AGM battery around 240 euros.

Here you will find information about the battery service of ADAC breakdown assistance. We have also listed useful tips for you on what to do if the car no longer starts.

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