Alpha Technologies XM3-HP Series - Technical Manual - Manual (Page 20)

20 017-882-B0-001 Rev. C2 (10/2013)
1.0
Introduction
1.2 Theory of Operation, continued
1.2.3 Charger Modes of Operation, continued
4-Stage Battery Charger (BULK/ACCEPT/REFRESH/FLOAT):
This preset value is applied to AlphaCell GXL batteries when selected in the Smart Display Menu.
A 30-minute REFRESH charge is added, after BULK and ACCEPT states, before dropping down
to FLOAT state, when the batteries are discharged more than 30% and it has been more than 30
days since the last REFRESH charge.
A manual REFRESH charge mode is recommended to be applied to all new batteries upon
installation. This mode “boosts” the individual cell voltage of batteries that may have been in
storage before they were placed on permanent FLOAT. Refresh can be initiated manually via
menu selection or automatically when the battery date code is updated (See Section 3.3.2,
Battery Information and Configuration for further instructions). The REFRESH charge is a one-
time, 24-hour charge to raise individual cell voltage to 2.45VDC, and may bypass the BULK and
ACCEPT states if the batteries are fully charged. The batteries are temperature-compensated at
-0.005VDC per cell per degree C to ensure safe battery cell voltage and maximize battery life.
Fig. 1-3, 4-Stage Charger Modes
BULK
Constant
Current Mode
(10A max) until
battery voltage
reaches the
ACCEPT level
(2.40V/cell)
ACCEPT
Constant Voltage Mode
(2.40V/cell) until battery
current demand drops
below .5A or time out
based on 4 minutes per
Ah battery capacity
FLOAT
Constant
Voltage
Mode
(2.27V/cell)
REFRESH
Constant
Voltage Mode
(2.45V/cell)
for 30 minutes
Battery Voltage
Battery Current
1.0 Introduction, continued