Introduction - Conrad Electronic CHARGE MANAGER 2010 Operating Instructions Manual

1. Introduction

Accumulators consists of two electrodes which are in an electrolyte; so an accumu-
lator is a chemical element. Inside this element chemical processes are active. As
these processes are reversible accumulators can be recharged.
This accu charger is constructed to charge and discharge up to four nickel-cadmium
and/or nickel-metal-hydride accumulators. The nickel-cadmium accumulators have
a positive electrode made from nickelhydroxide and a negative electrode from meta-
lic cadmium. The electrolyte consists of kaliumhydroxide. Nickel-metal-hydride
accumulators have a positive nickel- electrode and a negative hydride accumulating
electrode. The electrolyt is potash lye.
To charge up an accumulator the so called charging voltage is necessary which is
higher than the cell voltage. During charge more charge (mAh) has to be added as
you can take from it. This relation of added and taken charge is called efficiency.
The discharging capacity which is strongly dependent on the discharging current is
decisive for the condition of the accumulator. The voltage added cannot be used as
criterion because a part of it is lost (e.g. is converted into heat).
The capacity which is printed on the accumulator is the maximum charging capacity
which an accumulator is able to give off. This means an accumulator with a capacity
of 400 mAh can theoretically give off e.g. for one hour a current of 400 mA (= 0,4
Ampere). These values depend strongly on many factors (such as condition of the
accumulator, discharging current, temperature etc.).
At charging units the name C- rate is used very often. The C- rate is the current value
which is normally stated for charge and discharge. This current in Ampere corre-
sponds to the nominal capacity in Amperehours; this means for an accumulator with
400 mAh that 1C = 0.4 A.
Note that the discharge capacity of an accumulator strongly depends on the
discharge current: the lower the discharge current the greater the dischargeable
capacity. At automatic mode the discharge current is adapted automatically to the
condition of the accumulator. At manual mode discharge is C/3 at average.
Respectable manufacturers state the capacity of an accumulator at C/3. That means
e.g. that an accumulator with 1200 mAh will reach this 1200 mAh at a discharge cur-
rent of 400 mA (= C/3). If a discharge current of C/10 (= 120 mA) is stated you can be
sure that this accumulator doesn't reach 1200 mAh at a discharge current of 400 mA.
Because of this the accumulator stated with C/10 is not so good as the C/3 one.
If accumulators are stored over a longer period of time they loose charge. This effect
is called self- discharge.
4
2. Saftey Rules
This charging unit in constructed in protection class II; it may only be connected to
230 V AC.
With this charging unit it is only allowed to charge and discharge up to four nickel-
cadmium and nickel-metal-hydride accumulators of size mono (UM1/D), baby
(UM2/C), mignon (UM3/AA), micro (UM4/AAA) and lady (UM5/N) at the same time.
With this charger it isn't allowed to charge lithium- ionic accumulators!
Do not charge batteries besides nickel-cadmium and nickel-metal-hydride.
The VDE regulations are valid; especially DIN VDE 0700 part 29.
The maximum voltage at the connection pins of the charging unit is 5.5 V (high resi-
stance).
Keep children away from power supplies and charging units!
Pay attention to the rules for prevention of accidents in industrial enterprises prescri-
bed by the Industrial Trade Associations for electrical installations and production
facilities.
When using the charging unit in schools and hobby- workshops the usage of power
supplies and charging units has to be controlled by responsible teachers or skilled
personell.
If covers are opened or parts are removed, except it is possible manually, voltage-
carrying components can lay open. Terminals can also carry voltage. If it is neces-
sary to open the unit before adjustment, maintenance, repairing or exchange of parts
or modules, the charging unit has to be separated from all voltage sources. Repairing
or maintenance of the charging unit may only be executed by SKILLED PERONELL
who know the dangers and the respective rules.
Condensers in the unit can still carry voltage even if the unit has been separated from
all voltage sources.
Don't use the charging unit immediately after bringing it from a cold into a warm
room. Condensed water might impair or destroy your unit. Give the charger time to
warm up to room temperature without switching it on.
When working with power supplies or charging units it is not allowed to carry metal-
lic or conductive jewlery like necklaces, bracelets, rings etc.
5