and more often it is not possible to install radios ... - Herman Josip doo

After choosing the right cable cross section, it is very important to use the
same cross section for the negative cable. The right location of the mass
connection is an important basis for an installation free from unwanted
signals. For this reason we advise you to choose a highly conductive point
of bare metal on the body of the car. But be careful, the sheets of the trunk
are often just glued, which sometimes is unrecognizable due to an excellent
paint job. Alternatively the mass conductor can be led back to the
negative pole of the battery. If you are looking for a good central mass
connection, you should consider big solid screws, which generally have
excellent contact with the chassis.
The charging current delivered by the generator can also cause
unpleasant interferences. This charging current mainly consists of direct
current that is superposed with alternating voltage. Depending on the
frequency, these alternating voltages sometimes have very strong glitches.
If additional consumer units are connected e.g. the heating, the ventilation
etc. the proportion of the alternating voltage is rising. These interfering
alternating voltages can stray into the signal path of the car-hifi-system.
For this reason you should try to separate the power supply from the
signal cabling. Furthermore, the electric circuitry of the car and the original
cable trunks should be avoided when installing the car-hifi cables. These
highly capacitive and induced fields sometimes appear in neighbouring
conductors and disturb the sound quality extremely. The glitches can be
evened by the use of an anti-interference capacitor (article 530 by Dietz)
installed directly in the charging cable of the generator. If there is more
than one mass connection for the car-hifi system, the result will be mass
loops, so called potential differences. They can be avoided, as mentioned
before, by using one central mass connection for all components of the
car-hifi system. If there are still interferences, it is possible to pull in
bonding conductors.
For example, the generator mass can be connected with the negative pole
of the battery. Another bonding conductor can be drawn between the mass
connection of the radio and the antenna mass. In some cases, a
connection between the RCA mass and the antenna mass may be
successful. If none of these measures is successful the only solution is an
interference suppressor. It is available for the RCA cable as well as for
the power supply.
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b) Second battery
frequently asked question in this context is: Is my generator able to
Acharge two batteries or my high-current battery? The answer is: yes, it
is possible, but it takes longer until it is completely charged. Short distance
drivers ought to think about buying a generator delivering a higher
charging current. In case two or more high current batteries are used, it is
really necessary to buy a bigger generator. If it is handled correctly and if
it is charged from time to time, the battery’s life can be extended. When
charging a high current battery it is important that the voltage applied to the
terminals never passes 15V. So, when is it necessary to buy a high current
battery? In general: from 500-Watts Sinus on it makes sense buying a high
current battery.
From 1000-Watts Sinus on the original battery normally has the function of
a starter battery and supplies the car electric. The only task of a later installed
high current battery is to supply the car-hifi components. Presumed that
the charging power is sufficient, you can add an unlimited number of
consumer units. Cars equipped with a great number of consumer units as
board computer, air conditioning, several window defrosters, independent
vehicle heater, heated seats etc. and a powerful car-hifi system, should
always have a second battery, if possible a high current battery. A high
current battery has two decisive advantages compared with an originally
installed battery. First, the internal resistance is lower; second, the cold test
current is higher. These two factors influence the quality of the music
enormously.
An excellent sound presentation as well as perfect impulse fidelity are only
guaranteed, if the internal resistance is as low as possible (less than
3,0mOhm) and if the cold test current is much higher (at least 700 Ampere)
than in a usual battery. The indication ampere-hour (Ah) is more relevant
for the permanent use of a heater. But it does not matter at all if 50 Ah or
more are indicated.
It is often very difficult to find a place to install the second battery in the car.
In most cars there is no space left in the engine compartment, so the only
possibility to install the battery remains the trunk. Concerning the cable
length, this location offers an important advantage: the loss of power on
the way to the output stage is much lower. You should pay attention to a
stable and secure installation. Good air circulation is important in case of
gas leakage. For the installation of the second battery a high-current relay
is necessary (HCR 180); it is installed in the charging conductor between
the first and the second battery. The cable up to the input of the relay must
be equipped with an adequate fuse. The relay is opened and closed by the
ignition.
That means if the second battery is discharged, it is still possible to start
the car. Compared to insulation blocks working with diodes, a relay, due to
its construction, does not cause a power loss. In spite of the advantage of
making it possible to start the car, harmful discharges should be avoided.
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