BST100 MANUAL
before checking, to achieve the accurate data.
6-3 Can this tester predict when the battery goes down?
The internal resistance of the sealed lead-acid battery is complicated. It is generated by ohm
internal resistance, concentration polarization internal resistance, chemical reactions internal
resistance and interference effect caused by double capacitance’s charging. The ingredient of
internal resistance and its relative content will change with different test methods and different test
moments, which can lead to different tested values of the internal resistance. And there is no strict
relationship between internal resistance (or conductance) and capacitance of the sealed lead-acid
battery. So it is impossible to predict the life of battery according to a single battery’s internal
resistance. But it can be predicted the life of the battery will be over soon from the sudden increase
of its internal resistance and decrease of its conductance.
6-4 Is the CCA value tested by this tester correct?
CCA is considered as a control standard with the produce of the battery. According to the
accumulated records, the tested value of a new battery is 10-15% higher than the standard value,
and along with consuming the battery, the value is getting close to standard, even lower afterward.
6-5 What is the difference between the method used by this tester and the load test method?
The load test method: According to the physical formula R=V/1, test equipment forcibly makes the
high permanent DC ( presently 40-80A large current is available ) go through the battery shortly
( about 2-3 seconds). And then the tested voltage of the battery can be used to figure out the
internal resistance by the formula.
Disadvantages of the load test method:
(1) Only available for large capacitance battery or storage battery. The small capacitance battery
can not load 40-80A large current in 2-3 seconds.
(2) When the large current going through the battery, there comes out a polarization phenomenon
from the internal electrode, which can cause polarization internal resistance. As a result, it has to be
tested in a short time. Otherwise, there will be a large error in the internal resistance value.
(3) The internal electrode will be damage generally when the large current goes through the battery.
The method of this tester: Battery is equivalent to active resistance. So we add a fixed frequency
and small current to it and then sample the voltage value. Eventually, the internal resistance can be
figured out after some operation such as rectification and smoothing.
Advantages of this method:
(1) It can be used for checking almost all the batteries including low capacity battery and internal
resistance of the notebook battery exclusively.
(2) It will not harm the battery by using this method.
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