How do I charge my car battery properly?

In practice, it turns out that it does not matter whether the battery (batterie ladeerhaltungsgerät) is discharged because you forget to turn on the lights, listen to music for an hour while parked in the car, or because you stay in one place for a long time. The main thing is to follow some simple rules for proper operation of your battery saver car and be responsible with this issue.

A little theory

All batteries can be divided into different types: low-maintenance, maintenance-free and completely maintenance-free. At this point, it should be noted that the term "maintenance-free" in car batteries means an extension of refilling intervals with distilled water or the absence of such a need. All operating conditions of a maintenance-free car battery should be monitored in the same manner as the other parts of the vehicle.

Of course, each type differs in terms of operation and charging. All the details are described in the manuals that you should ideally have, but if you do not have them, our tips will be very useful.

Low-maintenance car batteries with grids of lead-antimony alloy are the "oldest and very rare today" and completely maintenance-free batteries with grids of the purest lead are the most popular and widely used.

The principle of operation of lead-acid batteries, which we will talk about today, is based on a chemical reaction between the plates and the electrolyte. The tandem of these two components generates electricity. Over time, the plates sulfate and decay, the electrolyte boils out, and the battery loses more than 60% of its capacity. As a result, your car won't start when you need it most.

How do you properly charge a battery?

Let's define what "proper charging" means in general. But before that, a few introductory words that are very important and apply to all types of car batteries: The less frequently the battery is discharged and the less deep each discharge is, the longer the battery will last. If a supposed expert tells you to regularly discharge the battery to the minimum and then charge it to the maximum, you should stay away from such advisors. Batteries whose parts are made from low-quality raw materials may benefit from such shocks, but they are a no-no for quality batteries. The reason is this: since the plates of cheap car batteries are covered with dirt, such "shocks" in the form of discharge/charge help to get rid of the dirt on the plates and allow electrolysis to circulate properly.

For batteries of the first class, the constant state of charge, also called buffering, is acceptable. This is the case when there is no discharge at all and the battery itself has a permanently controlled voltage.

How long should I charge the battery?

The length of time it takes to charge a battery depends primarily on the degree of initial discharge. It is also a question of charging capacity and useful life, because the longer a car battery is in use, the faster it replenishes its energy reserves.

The charging process of a lead-acid car battery consists of three steps:

• Quick charge (booster)
• Saturation
• Charge maintenance

A fully charged battery is indicated by a current drop of 2-3 mA per Ah capacity of the battery (in fast charge mode).

To illustrate, let's take the same 100 Ah C10 battery: a drop in charge current between 200 and 300 mA indicates that the battery is almost fully charged. For a full charge to 100%, this milli current is still required for about 60 minutes. On average, charging a car battery at constant current takes about 10 hours, while charging at constant voltage takes about 24 hours.

What is the right temperature for charging?

The temperature range for optimal charging is 0 ... +25 degrees Celsius. The colder it is outside, the less willingly the car battery will accept a charge. In some cases, it is permissible to charge the battery at sub-zero temperatures because the battery case warms up and the electrolyte temperature rises above zero. The situation is the same as with the alternator, which charges the battery even at -30°C.

It is inadmissible to charge a battery in extreme cold when it has been exposed to sub-zero temperatures for a long time, as the electrolyte may be frozen. A frozen battery should be moved to a warm room and wait until the ice has melted before charging.

Source: https://riewes.de/