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Hi all, not long had my 2.1 petrol x type, trying to resolve a few problems, today being interior lights flickering when idling, with my multimeter i checked continuity to earth form the alternator body, and for sanity checked continuity to live battery terminal to alternator body, low and behold i have continuity!! WTF?
 

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You will have, unless you disconnect the battery as it's a circuit. Did you use a low reading ohm meter or just a usual bell tester?
 

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I guess you have done the usual battery / alternator multi-meter test, which should show a minimum of 12.5v with the engine off at the battery and with the engine running around 14.2 - 14.6v to show the alternator(and battery) are in good health (dropping to but no less than 10v when cranking) ?
 

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!5v at idle is a bit high, you could be cooking your battery. Normal at idle should be about 13.9v to 14.2v and as Willowbob says should not drop below 10.5v at cranking as this will prove that the reserve has gone.
The high reading could be that the battery is not taking the charge. When you have the multimeter on does it fluctuate or is it static.

Roger
 

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It has a 2-stage charger. The first stage takes the terminal voltage up to 15.4v from a few minutes running up to half an hour, depending on ambient battery charge. It then drops down to 13.6v for the stage 2 float charge.
 

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Yes, sorry, I agree with Ice Cube the petrol has a two stage charger as described. From the workshop manual.

The engine control module (ECM) can switch the voltage regulator between two voltages to optimize the charging of the battery.
The low voltage regulator setting is 13.6 volts and the high voltage regulator setting is 15.3 volts, measured with the generator at 25°C
(77°F) and charging at a rate of 5 amps. These values decrease with a rise in temperature or current flow.
The ECM determines the voltage setting of the voltage regulator. The high voltage setting is always selected by the ECM once the vehicle
has started. The ECM determines the period of time that the high voltage setting is selected for.
There are three different time periods selected by the ECM which is dependent upon the vehicle conditions when the vehicle is started:
The longest time period is selected if the ECM determines that the vehicle has been 'soaking' for sufficient time to allow the engine
coolant temperature (ECT) and the intake air temperature (IAT) to fall within 3°C (37°F) of each other.
The intermediate time period is selected when the ECT and the IAT is below 5°C (41°F).
The shortest time period is the default time and is used to provide a short period of boost charge.
At the end of these time periods the voltage is always set to the low voltage setting to prevent the battery from being overcharged.
The time periods are variable depending upon the temperature and the battery voltage. The target voltage of the battery varies between 14
volts and 15 volts depending upon the ambient temperature and the vehicle operating conditions. Once this target voltage has been
achieved, providing the vehicle has been operating for at least the shortest time period, the ECM will reduce the voltage regulator to the
minimum setting of 13.6 volts
15.3 volts. If the wire is short circuit to ground, the generator will charge the battery at a setting of 13.6 volts.
A fault in the wiring or the connections from the generator to the ECM, will cause a fault code to be generated and stored in the ECM and
the charge warning indicator lamp to be displayed in the instrument cluster (IC) after a short time.
The charge warning indicator lamp is operated by the IC after receiving a signal from the ECM through the control area network (CAN).
With the ignition switch in the RUN position the charge warning indicator lamp will be displayed in the IC when the generator is not
generating power.
If a fault is detected with the generator a fault code will be generated and stored by the ECM. The charge warning indicator lamp will also
be displayed in the IC.

If your s is charging at 15v continuously then you could have a problem as above.

Roger
 

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Let's just clarify how the terminal voltage varies during the stage 1 bulk charge phase. The alternator attempts to supply an EMF of 15.3v (possibly as high as 16v) just the same as a benchtop battery charger set on 'High'. But the condition of the battery allied to the high charge current pulls this voltage down at the terminals. The voltage gradually rises towards the EMF voltage and the current reduces, as the battery accepts the bulk charge. This is why a typical reading of 14v or more is measured at the terminals during the stage 1 phase. Once the terminal voltage reaches 15.3v, the battery will start to gas, and the gassing will continue as long as the terminal voltage exceeds 14.3v (for calcium, but conventional antimony is slightly less), which is why the EMF is smartly dropped down to 13.6v for stage 2.
 
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