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Printouts from a battery discharge test
This page shows printouts from the Batscan program after a discharge test recently performed on a UPS-battery. The battery consists of 2 parallel strings with 68 6V block in each string. Each block contains 3 cells, and each string has 204 cells.The battery type, that is one of the most common on the market, has a design live of 10 years, an complies to the requirements of "Eurobat's classification High Integrity (10+)". The batteries are manufactured according to UL 94 HB, IEC 896-2, and the DIN 43534 standard.
The battery has been in use for 2 years at the time of testing.
Battery Type: VRLA, AGM
Nominal Battery Voltage: 408 Volt
Total Battery Blocks: 136
Total Battery Cells: 408
Nominal Block Capacity: 162 Ah (C10 to 1.80 Volt/cell)
Constant Power during the test: 96.86 kW/string (1424W/block)
Calculated Battery runtime at this load: 19.1 minutes
Calculated end voltage: 1.60V/cell, 4.8V/block, total battery voltage 326.4V
Conclusions from the test results
- Of the totally 136 battery blocks that was included in the test, 5 blocks (=4%) did not pass the test.
- Each battery string contains at least one failing block.
- One block failed after less than one third of the expected time.
- In 4 of the 5 failing blocks, at least one cell reversed polarity, with the risk of an explosion.
It should be noted that all the other blocks seems to be in good condition and shows no signs of weakness at the end of the test.
The fact that 4% of the blocks need to be replaced after 2 years of service in stand-by mode is normal for this type of battery. With Batscan it is easy to identify failing blocks and after replacing them the battery is restored to its full capacity.
Without replacing the failing blocks there will be a risk for an open cell condition at the next discharge, and then it will be of little help that all the other 131 blocks in the battery are perfectly OK.
Click on the graph to show labels.
Click on the graph to show labels.