Battery Test Function - Elektro-Automatik ELR 9000 Betriebsanleitung

ELR 9000 Series
3.9.13

Battery test function

Function "Battery test" is only available with electronic loads and is used to dis-
charge various types of batteries with specific parameters defined by the user.
There is basically the choice to select between static and dynamic test mode.
The static battery test will discharge a connected battery with a constant
current or constant resistance, down to the adjustable discharge voltage
(short: U-DV) and then stop. Alternatively, the test can also stop upon two
other criteria, a maximum time or a maximum battery capacity consumed by
the load, whatever is achieved first.
The device measures its input current over time and calculates the consumed capacity in Ampere hours (Ah).
During the test it will also monitor the battery voltage, here it's the input voltage on the DC input, for reaching the
threshold U-DV.
The dynamic battery test can make use of two adjustable current values together with time in order to discharge
a battery in pulsed mode (rectangular wave). Constant resistance settings are not available in this mode.
Something that is not a problem with lead-acid batteries, but can be a problem more sensitive battery type, such
as Lithium ion, which are much more sensitive about battery voltage: the reaction time of the load device when
stopping the test due to reaching the U-DV threshold, i. e. switching off the DC input. This reaction time is not
adjustable, but is almost zero. In fact, it ranges from 5-20 ms.
When discharging with high currents, compared to the nominal battery capacity and in dynamic mode, it may hap-
pen that the battery voltage shortly drops below the U-DV threshold and the test will unintentionally stop. Here it
is recommended to adjust U-DV accordingly.
Graphical depiction of both battery test modes:
U, I
U-DV
Discharge current
Start
Static
3.9.13.1 Static mode
The following parameters can be configured for function "Battery test" in mode "Static":
Value Range
I 0...Nominal value of I
P 0...Nominal value of P Additional power limitation in Watt
R OFF, R ...R
Min Max
Further parameters and settings which are identical for both modes are explained below.
After the configuration is done and the function has been loaded, the test can be started. The load will then discharge
the battery with either a constant current (CC) or constant resistance (CR) or constant power (CP), depending on
the settings. When activating CR mode it has priority over CC mode. Contrary to CC mode, the current will rise (if
not limited by the parameter "Discharge current") with the sinking battery voltage in order to keep the resistance
constant.
The additionally adjustable power limitation (CP), which would also affect CC and CR mode and limit their settings,
should be set to or left at 100%, if not used. The same applies if CR shall not affect CC mode discharging. Then
it is recommended to set the "Discharge resistance" parameter to OFF.
EA Elektro-Automatik GmbH
Page 78
Helmholtzstr. 31-33 • 41747 Viersen
Germany
U, I
U-DV
Discharge current
t
Start
Stop
Dynamic
Description
Discharge current in Ampere
Discharge resistance in Ohm
t
Stop
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Fax: +49 2162 / 16230
www.elektroautomatik.de
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