everActive UC-4200 Bedienungsanleitung Seite 10

8. Internal resistance measurment.Internal
resistance measurment.
Charger has an unique function that can test the internal
resistance (IR) of inserted cells. The test is carried out
automatically just after the battery is placed in any of the slots.
This is very usefull to determine in what condition is the battery.
Together with capacity test it's all you need to have a full
knowledge about your battery health. Please note that the IR
measurement is very sensitive and there can be some
measurement errors for example the IR result obtained in a new
charger can be a bit too optimistic, especially with Li-ion
batteries. The IR results tend to increase due to aging of
batteries and charger (due to increased contact resistance). As
for the consumer grade charger the IR results are very accurate
and allow to easily compare the cells between each other. For
optimum results the battery should be charged in about 30-70%.
Measuring the IR on the discharged or nearly charged battery
may bring false results.
How to read IR results (lower is better):
Ni-MH
<70 mΩ – high quality/new cell
with high output capabilities,
70-200 mΩ – increased
internal resistance, limited
performance in high drain
applications, less reliable
operation,
200-500 mΩ – it is
recommended to run refresh
cycles and check the value
again. If there is no
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Li-based
< 30 mΩ high quality/new cell
with high output capabilities,
30-150 mΩ typical cell for low
drain applications or a cell with
integrated PCM (electronic
protection module)
150-250 mΩ - increased
internal resistance, should not
be used in high drain
applications,
>250 mΩ – not a typical and