Points To Be Noted And Observed When Testing Starter Batteries; General Information; Essential Inputs; Important Information On Battery Testing - Bosch BAT 171 Betriebsanleitung

en 16 | BAT 171 | Points to be noted and observed when testing starter batteries
4. Points to be noted and
observed when testing
starter batteries
4.1

General information

The portable battery tester is designed for mobile
applications and is used for the no-load testing of 12 V
batteries. Testing can be performed with the 12 V
batteries both fitted in and removed from the vehicle.
The BAT 171 can also be used outdoors.
!
The BAT 171 is only designed for 12 V batteries
(standard or VRLA). Undervoltage is registered with
6 V batteries and overvoltage with 24 V batteries.
i
For battery testing the BAT 171 has to be connected
to the battery posts. The battery need not be
disconnected from the vehicle electrical system
during battery testing. The battery test assesses the
battery on the basis of an impedance measurement
between the battery terminals (Kelvin connections).
Any further ohmic resistance is assigned to
the battery and would lead to a poorer battery
assessment than is actually the case.
Hairline cracks in the lead plate links:
Extremely fine cracks in the lead plate links (hairline
cracks) are sometimes only detected on subjecting the
battery to a high current load (e.g. battery test under
load). In borderline cases, no-load battery tests (as
performed for example with the BAT 171) do not detect
such hairline cracks. The occurrence of hairline cracks
of this type is extremely rare with modern batteries.
No-load voltage below 12 V:
If the no-load voltage is less than 12 V over a lengthy
period, the battery can be assumed to be not in perfect
working order. A no-load voltage below 12.4 V is an
indication of a permanent charge deficiency of the
battery. This may be caused for example by a defective
alternator or regulator, contact resistance as a result
of a loose or contaminated battery connecting cable,
a loose V-belt or use of the vehicle for frequent short
journeys.
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1 689 989 061 2009-10-16
4.2

Essential inputs

Cold start current and test standard:
For battery assessment, the BAT 171 must be provided
with the cold start current in amps and the test
standard (IEC, DIN, SAE, EN, JIS) as reference values.
Correct entry of these reference values is a prerequisite
for accurate battery testing.
Battery temperature:
The starting performance of a battery is highly
temperature-dependent. To obtain reliable test results,
it is essential to enter the battery temperature range
(less than 0 °C or greater than 0 °C) in addition to the
cold start current and the test standard. When selecting
the temperature range, the battery temperature and not
the ambient temperature is definitive.
4.3 Important information on battery
testing
Battery testers give an indication of the instantaneous
status of a battery. Every time a battery is charged or
discharged, this influences its status. If the status of a
battery is close to the Good/Replace limit, the results
of two consecutive tests on the same battery with
intermediate charging or discharging may alternate
between "good" and "replace".
i
If the test result for batteries less than 3 years old
is "REPLACE BATTERY", it is always advisable to
additionally check the no-load current, the charging
circuit and the charge balance (e.g. battery charge
deficiency on account of frequent short journeys).
New, ready filled starter batteries which have been
stored for lengthy periods generally only attain their
full starting capacity after several weeks of use in the
vehicle.
Dry charged batteries only attain their full capacity
several hours after filling with electrolyte.
!
Testing dry charged batteries immediately after
filling may bias the test result.
i
The battery test yields the best results on batteries
which have been allowed to stand for at least one
hour after charging or following high current draw
(starting).
Robert Bosch GmbH