ROBBE Power Peak E1 Mode D'emploi page 50

Charging parallel-wired cells does not pre-
sent problems, as the total charge current is
distributed to the individual cells according
to their voltage.
We accept absolutely no liability for
damage caused by incorrect or incompe-
tent handling of the cells. Please be sure
to read and observe the Safety Notes.
Temperature differences always occur
during the discharge process, as the outer
cells are inevitably cooled more effectively
than the inner ones. The effect of this, com-
bined with normal manufacturing toleran-
ces, is that the state of charge of series-con-
nected Lithium-Polymer cells always tends
to drift.
After several discharge / charge cycles
individual cells invariably exhibit diffe-
rences in voltage.
Operating instructions
Power Peak E1
21.
Explanation of "Delta-peak" charge ter-
mination
The graph above shows the typical charge
curve of an NC or NiMH battery.
At the end of the charge process the pack's
internal resistance changes as the cells
heat up.
This results in a slight decline in cell vol-
tage.
Battery chargers which terminate the
charge process exactly at the highest point
of the charge curve are known as "Zero
Delta-Peak" chargers.
To compensate for charge losses as the
cells cool down, or to increase the perfor-
mance capacity of a battery for competi-
tion use, it has become normal practice to
overcharge these packs slightly - to an
extent which varies according to the cell
type.
The peak sensitivity, or Delta-Peak value,
is stated in the form of 5 mV / cell or a simi-
lar value. This indicates the overcharge
value, i.e. the process is terminated slightly
later than the peak.
Setting the Delta-Peak sensitivity to 15 mV
causes the battery to be extremely fully
charged, and the pack will then be hot to
the touch. This type of charge does provide
high battery energy, but at the same time it
has a massive negative effect on the useful
22
Order No.
8471