017-220-J0 Rev C
74
10.3 Using the Equation
The following example shows how to calculate Peukert number and capacity from a configured battery string.
Consider four CSB EVX1272 batteries connected and configured as shown in the figure below. Two of the four bat-
teries are connected in series, and the two series strings are connected in parallel to the 24Vdc output. The load of
the inverter is 85W. For a 24Vdc string the calculated discharge current is 3.54A.
Figure 53 — Battery String Example
The Peukert number and capacity for the above configuration can be determined as follows:
1. Obtain the data sheet of the selected battery. See table below.
2. Find the current discharge ratings table in the data sheet, use 1.75V. From the table, pick two current discharge
values (I
1
and I
2
) that are closest to the calculated load current value. Look up the two discharge hours (R
1
and R
2
).
3. From the table, I1 = 2.34A, I2 = 1.82A, R1 = 3hrs, R2 = 4hrs.
From equation earlier:
Peukert’s number = n =
Log (R
2
/R
1
)
(Log (I
1
) - Log (I
2
))
EVX 1272
12 VDC
EVX 1272
12 VDC
EVX 1272
12 VDC
24 VDC
EVX 1272
12 VDC
+
▬
▬
▬
▬
▬
+
+
+
+
Constant Current Nominal Ratings in Amps (@ 25° / 77° F)
Discharge Time
2min
4min
5min
6min
8min
10min
15min
20min
30min
45min
60min
90min
2hr
3hr
4hr
5hr
1.60V:
74
50
42.2
36.8
29.6
24.9
18
14.2
10.3
7.36
5.84
4.21
3.31
2.37
1.84
1.51
1.67V:
67.3
47.5
40.7
35.8
29
24.5
17.8
14.1
10.2
7.34
5.82
4.2
3.31
2.36
1.83
1.5
1.70V:
64.1
45.9
39.7
35.2
28.6
24.2
17.7
14.1
10.1
7.33
5.81
4.2
3.3
2.36
1.83
1.5
1.75V:
58.3
42.8
37.5
33.6
27.6
23.5
17.4
13.9
10
7.27
5.77
4.17
3.28
2.34
1.82
1.49
n=
= 1.145
Log (4/3)
Log (2.34) - Log (1.82)
Summary of Contents for Alpha Micro 100
Page 1: ...Alpha Micro 100 UPS Technical Guide 017 220 J0 Effective 09 2020...
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Page 36: ...35 017 220 J0 Rev C Figure 14 Web Interface Bulk Charging Menus...
Page 37: ...017 220 J0 Rev C 36 Figure 15 Web Interface Bulk Charging Menus...
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