Order No.
8294Li/D
Supplementary operating instructions
POWER PEAK Infinity 2 LI
10
Charging battery packs
Integrated charge protection circuit
Each Li-Poly cell usually contains a voltage
monitor module to protect it from overchar-
ging, deep-discharging or excessive cur-
rents.
However, for modelling applications it is
usual to draw high load currents, which
means that the monitor module would very
often be tripped to protect the cells. For this
very reason most battery packs do not
include this feature.
The lack of the protective circuit can gene-
rate problems in the charging of series-wired
Li-Poly cells. As mentioned earlier, individual
cells in the pack may well have slightly diffe-
rent charge states and voltages.
In this case the overall final charge voltage is
not distributed evenly amongst the individual
cells, with the result that cells featuring hig-
her voltage can easily be overcharged.
To avoid this, the individual cells must be
brought up to the final charge voltage of 4.2
(or 4.1) Volts.
In contrast, charging parallel-wired cells
does not present problems, as the total
charge current is distributed to the individual
cells according to their voltage.
We wish to point out expressly at this point
that, in the interests of safety, Li-Poly batte-
ries may only be charged using the Infinity 2
Li charger if each individual cell is fitted
with a voltage monitor module.
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 regarding the handling of Li-
Poly cells; you will find them at the end of
these instructions.
The charge process
Lithium-Ion batteries are charged using the
constant voltage method.
For this reason the final charge voltage is
pre-set on the charger according to the
number of cells in the pack.
During the initial charge phase the battery
voltage rises slowly to the maximum value of
4.1 or 4.2 V / cell. In this phase the Infinity 2
Li charger ensures that the charge current
remains constantly at the pre-set value.
At a charge current of 1 C and a discharged
battery this initial phase lasts about 50 to 60
minutes, and during this time about 80% of
full battery capacity is charged in.
During the second phase the charge current
falls off, since the difference in voltage bet-
ween charger and battery is steadily decli-
ning. A further 35 - 40 minutes is required in
order to charge in the remaining capacity.
The unit switches off the charge process
when the charge current falls to the bottom
limit of 50 mA.
At present the permissible maximum charge
rate is 1 C, and this means that the total
charge process takes at least 90 minutes if
the battery is initially discharged.
