Alpha Technologies AlphaCellTM SMU-C Series - Manual (Page 13)

13 745-680-B11-001, Rev. A
Table 2-2, Discharge End-Voltage
Discharge Current (A) Discharge End-Voltage (Vpc)
I < 0.2C 10.5
0.2C ≤ I < 0.5C 10.2
0.5C ≤ I < 1.0C 9.30
I ≥ 1.0C 7.80
2.3 Discharge
The end voltage is the lowest voltage the battery can be discharged to without causing
damage. Usually, the 20 hour rate (C
20
) end voltage of a C battery is 10.5V/block. Although
the battery can be discharged below this voltage, doing so will not discharge any more
capacity and can affect its lifespan. It may be impossible to recharge a battery after several
over-discharges. After a discharge, recharge the batteries as soon as possible to maximize
battery life. See Section 5.0 for discharge specifications.
Table 2-1, Floating Voltage at Different Temperatures
Ambient Temperature ºF (ºC) Floating Voltage (Vpc)
32 (0) 13.73
41 (5) 13.72
50 (10) 13.71
58 (15) 13.70
68 (20) 13.69
77 (25) 13.68
86 (30) 13.67
95 (35) 13.66
104 (40) 13.65
2.2 Floating Charge
A float charge keeps the battery in a fully charged state with a small but constant current to
automatically cover capacity loss resultant from self discharge and other discharges.
At 25ºC, the proper floating voltage for the C series is 13.68V/block. The temperature
compensate coefficient is -32.4mV/ºF/block (-18mV/ºC/block).
CAUTION!
If the floating voltage is higher than indicated in Table 2-1, then the floating current is also higher
than ideal and will accelerate corruption of the grid and shorten the life of the battery. If the floating
voltage is lower, the battery will not be kept in fully charged state, which will crystallize the PbSO
4
(Lead Sulfate), decrease the capacity, and also shorten the life of the battery.
2.0 Charging Procedures, continued