Conrad ReFLEX 200 multi Bedienungsanleitung Seite 5

Unlike normal batteries that are charged during production, accumulators are
electrochemical storage cells that have to be charged before use.
The charge that a fully charged accumulator can deliver is specified by the
manufacturer in capacity units of mAh or Ah. The electric energy that is supplied
during charging is always higher than the energy that is taken out during
discharge, this is why it determines the accumulator efficiency. With NiCd and
NiMH accumulators, this is typically 0.72, i.e. approximately 140% energy has to
be supplied during charge.
The nominal capacity value indicates the maximum charge that the accumulator is
able to deliver. If, for example, an accumulator has a nominal capacity of
2000mAh = 2Ah, in the best case it will deliver a discharge current of 2000mA =
2A for 1 hour. The usable charge capacity is reduced by many factors (condition
of the accumulator, age, temperature, level of discharging current).
Definition of C rate for charging and discharging NiCd and NiMH
accumulators:
The C rate is a quantity very commonly used to specify the charging and
discharging currents. It is in proportion to the accumulator capacity and is
determined as follows:
C in A (= Ampère) is equivalent to the numerical value of the nominal accumulator
capacity in Ah (= Ampère hours). For example, if the nominal capacity is
1500mAh = 1.5Ah, then C = 1.5A. If this accumulator is charged with a loading
rate of 1/10 C, this is equivalent to a charging current of 150mA. A charge of the
same accumulator with 2C is equivalent to a charging current of 3A.
In order to determine the charging time of the discharged accumulator, the
charging efficiency has to be taken into account. The typical charge needed to
charge the 1.5Ah accumulator is 1.4 times as big as the nominal capacity: 1.4 x
1.5Ah = 2.1Ah. If the selected charging current is equivalent to 2C = 3A, the
resulting charging time is: 2.1Ah / 3A = 0.7h or 42 minutes.
When using the ReFLEX 200 multi charger, charging times can be reduced by
increasing the C rate.
Most accumulator manufacturers specify 1C as the usual boost charging rate.
This is assuming that the charging current is constant and not interrupted.
However, the reflex charging technology pulses the charging current and even
inserts short discharge currents during the breaks in the charging current. Thus, it
is possible to charge the accumulators with C rates of 1.5C to 2C as normal
charging currents.
With the ReFLEX 200 multi, NiMH accumulators can be charged with these
currents in the typical way. An increase in the C rate is only allowed if the
manufacturer permits this explicitly in the accumulator specifications.
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