Page 76 - Energize October 2022

TECHNICAL

Figure 2: Test setup for the test (water bath)

Figure 3: Overview of cycle 151-300

Figure 5: PVS batteries

Results
Figure 3 shows a typical timing diagram
of the single cells. The cell temperature
was between 39,4 and 41,6°C (required
40°C ±3 K), the mean value was 40,5°C.
In Figure 4 the results of the C10
capacity test done in each sequence are
shown. Both types, single cell as well as
block battery performed very well. The
block battery performed 2700 cycles, and
the single cells reached 3150 cycles.
Table 1 shows the numbers of A+B Figure 4: Endurance in solar cycles
sequences which were achieved.
We apply here the temperature Battery type Total cycles A + B sequences
correction factor for the number of
cycles and the cycle life used for traction PVS single cell 3150 21
batteries in ZVEI notes, Germany: Here PVS block battery 2700 18
a temperature difference of 20 K higher
equals a reduction of the number of cycles Table 1: Different notations of measuring results
of 50%. So, at 40°C we estimate the factor
to be 1, and at 25°C the factor would be Design Block design Single cell
1,60. Therefore, we can calculate the
number of cycles and the cycle life at Temperature 12V 3PVS 210 6PVS 420
different temperatures and obtain the Cycles 2700 3150
current results of the tests for actual 40˚C
temperatures. The service life in years was Years 7,3 8,6
calculated by the number of cycles divided Cycles 4320 5040
by 365 days per year (see Table 2). 25˚C
Years 11,8 13,8

Contact Silicon Engineering, Cycles 5400 6300
011 474-3423, 20˚C
sales@silicon-online.co.za, Years 14,7 17,2
http://www.silicon-online.co.za Table 2: Interpretation of test results

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