14
3.2 Charge programs explained
Most standard selectable charge programs, perform a four stage IUoUoP charging process
comprising of a “Bulk” , an “Absorption”, a “Float” and a “Pulse” stage. The image below
visualizes the four stage charging process (for typical 48V voltage values, please multiply the
24V values by 2):
In the Bulk stage, the charger delivers full output current and typically returns approximately
80% of charge back into the battery once the absorption voltage is reached. During this
stage, indicators 3d and 3c (see frontpanel image in chapter 4.1) will be lit depending on the
Bulk charge progress.
When the absorption voltage has been reached, the Absorption stage will be entered and
indicator 3b will be lit. This stage will return the final 20% of charge to the battery. The
output voltage is kept at a constant level and the charge current decreases as a function of
the battery's state of charge. When the charge current has dropped below a certain value or
when the maximum absorption timer has been expired, the Float stage will be entered.
Indicator 3a will be lit and an acoustical message will sound, indicating that the battery is
full. In this stage the battery voltage will be held constant at a safe level for the battery. It
will maintain the battery in optimal condition for as long as the battery remains connected
to the activated charger. Connected battery loads will be directly powered by the charger
up to the charger's maximum output current level. When even more current is drawn, the
