The characteristics of a battery are, the nominal tension, the capacity and the low temperature test current. It must be said that, the nominal tension gives only an approximate indication of the actual tension. The capacity is a measure of the storable energy. It is based on the consumption and on the average switch-on time. The battery illustrated above, can deliver, e.g., for a period of 11 hours, 4 A of current. At a power consumption for the ignition, of approx. 1.5 A, an Otto engine could run for approx. 15 hours, until the battery is half discharged. Thereafter the battery tension may not drop to less than 10.5 V. In addition, the maximum low temperature test current of 320A, which can be drawn at -18°C for a period of 30 seconds. The minimum cell tensions are also exactly specified. These values are important for a battery endurance test. The test is always carried out then, when not the momentary charge condition is to be tested, but the starting behaviour of the battery the next morning.
With dry, pre-loaded batteries, the resulting sulfuric acid is basically extracted by the manufacturer, and is provided in an additional container. Once refilled, this battery is ready for operation immediately. One recognises maintenance-free batteries by the missing or only difficult to access sealing plugs. When charging these batteries, one should avoid undue over-charging. This means all processes which do not occur in the automobile. Because charging currents of 100 A can also occur here, only extremely fast loading would probably be dangerous for older batteries.
A normal charging takes place with about 1/10 of the indicated Ah-capacity. The preservation charging provides only a compensation for the self-discharging process. The battery takes, with a max. of 14.5 V of charging voltage, only as much as it can cope with. This is particularly valid for batteries, that haven't been used for 3 - 6 months and are fully discharged. If no current flows after a longer period of charging, the battery should be replaced.
Under no circumstances, because of possible acid splashes, should batteries come into contact with clothing or with the skin. If acid does splash, e.g., into the eyes, from an exploding battery, only rinsing the eyes with a lot of water helps. The rinsing is, if possible, to be continued until professional help arrives. Should someone accidentally drink acid, the best thing to do is to make them drink as much water or tea as possible, but only if the person is concious. If acid-vapours were inhaled, intensive ventilation can help.
It goes without saying, that the affected articles of clothing are to be removed. The rinsing with water, water and more water should be continued. Under no circumstances should the person be left unattended, the more serious the incident, the more attention the person needs. Should the injured person be aware of what is happening, panic may set in. Working with acids requires that protective gloves and goggles are worn all the time. If splashing is to be expected, a protective overall is recommended. Quite often, accidents with acid cause permanent damage.
Although it is accomodated in the engine compartment, the battery is not suited as a repository for tools! If the poles are connected, e.g., by a spanner, it turns into a welding machine!. To avoid short circuits, the negative pole is always disconnected first when removing the battery, and always connected last when installing it again. To avoid high transitional resistance when starting, and also the accompanying heat development, the poles and their terminals should always be kept clean and greased to avoid corrosion. Of course the solid seating of the battery in the vehicle must also be ensured.
Nowadays, the terminal voltage, the charge- and discharge current and also the temperature can be recorded by a sensor directly on the negative pole of the battery and can be transmitted to a control device or to the garage-tester. 08/11