3 7
T O R K E L 8 2 0 / 8 4 0 / 8 6 0
P r o g r a m m a E l e c t r i c A B
Z P - B S 0 6 E R 1 0 1
TXL830
Max
voltage
Possible resistance
settings (nominal)
Position
28 V
0.275 W 1
0.138 W 2
0.092 W 3
TXL850
56 V
0.550 W 1
0.278 W 2
0.184 W 3
TXL870
140 V
2.480 W 2
1.240 W 3
280 V 4,950 W 1
Example
A lead-acid battery with 54 cells has to be tested at
250 A.
Voltage at the beginning of the test (Vstart) is:
116.1 V (54 x 2.15 V)
Voltage at end of the test (Vend) is:
97.2 V (54 x 1.80 V)
Since the current is so high, you must use TXLs . A
TXL870 is suitable since it is rated for the voltage in
question.
1 – Number of TXLs – Current flowing
through TXL(s) at beginning of a test.
The current through a TXL870 set for a resistance of
2.48 Ω is 46.8 A, and current through a TXL870 with
a resistance of 1.24 Ω is 93.6 A. If two TXLs are set to
1.24 Ω and one TXL is set to 2.48 Ω the current will
be 234 A, and they can be connected without having
the current exceed 250 A.
2 – Current flowing through TXL(s) at final
voltage.
234 A x 97.2 V / 116.1 V = 196 A
3 – Number of TORKELs – for the current
regulation.
250 A – 196 A = 54 A. A single TORKEL 840 is
enough for this.
4 – Are all of the TXLs needed?
The loading capability of the TORKEL unit is 110 A at
the final voltage. This exceeds the amount needed by
110 A – 54 A = 56 A. This unused margin is perhaps
wide enough to eliminate the need for one TXL. At
the end of the test, the current through the TXL that
is set to 2.48 Ω is 97.2 V / 2.48 Ω = 39 A. Since the
unused TORKEL margin is wider than 39 A, this TXL is
not needed.
TORKEL/TXL system exam-
ples
Systems containing TORKEL 820
and TXL830
12 V battery (6 cells)
Discharge from 2.15 to 1.8 V/cell
Maximum con-
stant current (A)
Number of units
TORKEL 820
Number of units
TXL830
234 1 1
346 1 2
459 1 3
571 1 4
693 2 4
806 2 5
918 2 6
1031 2 7
24 V battery (12 cells)
Discharge from 2.15 to 1.8 V/cell
Maximum con-
stant current (A)
Number of units
TORKEL 820
Number of units
TXL830
495 1 1
720 1 2
945 1 3
1170 1 4
1440 2 4
1665 2 5
1890 2 6
2115 2 7
2340 2 8
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