Self-Study Program

19
Critical energy balance
This data record is only written if the vehicle is in an energy critical state (breakdown risk). The data record is
written if the energy management control unit recognises the condition "vehicle cannot be started". The most
recent data record is displayed at all times.
Display on tester
This data record is only written if the vehicle is in an energy critical state (breakdown risk).
The data record is output together with the information in alphanumeric text. This simplifies evaluation.
Display on tester if no danger of breakdown risk existed
No entry exists. The vehicle is not in an energy critical state.
The "mean total current" is the value of "Engine OFF" up to the "limit of startability". It therefore gives the
average electrical current until an entry was made.
The "current up to time of history data entry" gives the electrical current at the moment of entry or at the
moment of breakdown risk recognition.
The "battery state of charge" is recorded at the moment of triggering.
The "battery internal resistance" is recorded at the moment of triggering. The battery should internal
resistance of less than approx. 10 Mohms at al times. If the internal resistance is greater than this, the battery
should be checked. Please note that the internal resistance increases rapidly after the state of charge drops to
15-20 %. In the case of a fully discharged battery, values up to 99 Mohms may be indicated.
With regard to the energy throughput, it should be considered that a battery can deliver approx. 60 x of its
rated capacitance over its useful life.
The energy balance is the battery's "account". If more current flows away from the battery than to the battery,
the value is negative. If the battery is fully charged, a 0 is displayed as the energy balance. As this value is
produced by current integration only, it loses significance with increasing battery age.
From the status of the lights and the vehicle, it can be ascertained whether an electrical consumer or the
ignition was "on" at the moment of recording, i.e. at the time of breakdown risk.
The "number of breakdown entries" indicates how often the energy management control unit has ascertained
an energy-critical balance which could lead to starting problems.
Generally, the history data must be read out rapidly in cases of complaint. If a new "breakdown risk" is
triggered by frequent ignition on/off cycles or short manoeuvres, the previous critical energy balance data will
be overwritten by the new data. This means that the data at the time of complaint is overwritten and therefore
lost, which, in turn, can complicate the problem handling process.
00.05 A, mean static current
19.75 A, mean total current
-10.73 A, current at time of history data entry
17 %, battery state of charge
03 Mohms, internal resistance of the battery
+0118 Ah, energy throughput
-00067 Ah, energy balance
009624 km, mileage
2005-06-13, 23:24:47 time and date
Hazard warning OFF
Side lights OFF
Low beam headlight OFF
Fog light OFF
Main beam OFF
07.1 hours, terminal 15 ON
07.1 hours, data bus awake
007.1 hours, previous standstill period
00 number of data bus ON/OFF cycles
01 number of terminal 15 ON/OFF cycles
01 number of breakdown entries in history database
002 number of fitted (replaced) batteries in vehicle
Light status
Vehicle status