Alpha Technologies Industrial Ni-Cd Batteries Standard Range - Manual (Page 19)

EN-ALPHA-TMSR-001 (10/09) 19
PR
EL
IM
IN
AR
Y
The Alpha Ni-Cd battery can generally be charged by all normal methods. Usually, batteries in parallel operation
with charger and load are charged with constant voltage. For operations where the battery is charged separately
from the load, charging with constant current is possible. Overcharging will not damage the battery but will lead to
an increase of water consumption.
6.1 Constant Voltage Charge
The common method to charge a battery in stationary applications is carried out by a constant voltage system
and the recommended solution is to use a two-rate type that is able to provide a constant voltage charge and a
lower fl oating voltage or single rate fl oating voltage. The two level charger has an high voltage stage to charge the
battery properly after a discharge followed by a lower voltage fl oat level charge. This results in a quick charge of
the battery and in relatively low water consumption due to the low level fl oat charge
Two level charge
Boost charge: 1.55 - 1.70 V/cell
Floating: 1.40 - 1.42 V/cell
A high voltage will increase the speed and effi ciency of recharging the battery. In reality, often single level charger
can be found. This is surely a compromise between a voltage high enough to charge the battery and low enough
to have adequate water consumption.
Single level charge
1.45 - 1.50 V/cell
For commisioning the batteries please see point 7.3.5 .
6. 0 Charging