General - Voltcraft Rim 1000 Bedienungsanleitung

4. General

For accumulators and, in particular accumulator packs, the
nominal capacity is the best-known technical information (for
example, "7.2V/3000mAh" is stated on a racing pack).
For the assessment of the accumulator/accumulator pack, the
capacity is important but does not state anything about the status
or the quality of the accumulator/accumulator pack.
One of the decisive criteria of assessment is the internal resist-
ance of the cells. This applies above all to high-current applica-
tions such as, for example, those in the model construction area
or for electrical applications.
High differences in price with individual cells or
accumulator packs with the same nominal capacity
can thus be justified.
The voltage situation amongst the load conditions (when high
currents are removed) can of course only be high when as little
voltage as possible is used by the accumulator itself and is
converted into heat.
For accumulators with a high internal resistance, the removable
capacity is relatively strongly dependent on the load conditions.
On the one hand, a great deal of energy is used for nothing on the
internal resistance and, on the other, the accumulator appears to
be flat through the breaking down of voltage although there can
still be a great quantity of residual energy.
Figure1: Simplified equivalent circuit diagram
As the simplified equivalent circuit diagram in fig. 1 shows, the
internal resistance R
a series connection.
R
i
of the accumulator and the load R
i
R
Last
forms
Last
25