StevieC Posted November 4, 2017 Report Share Posted November 4, 2017 Hi Everyone, New here but looking for some advice. I have a 2015 Journey with the 4 cylinder. (My dad is a mechanic and I'm pretty mechanically inclined myself so this one really does stump us both.) I have replaced the battery 3 times thinking the battery is some how at fault and now I'm thinking I have a charging system problem because while I have 14.4 volts at the battery and at the back of the alternator with the vehicle running it never fully charges the battery. I have fully charged the battery with a charger to a full resting voltage of 12.64 volts and done a stress (heavy load) test and it snaps back no problem. It also holds this full charge over night. After a few days of normal driving though it will drop down to 11.5 volts resting voltage when the car is shut-down despited driving for long trips (highway mainly) with charging voltage of 14.4v all the time. It's like it just isn't pushing enough current back into the battery and slowly wears it down after a few days. Then I have to drag out my big charger and charge it up manually. I have turned on all the accessories and load tested the alternator and it maintains 14 volts with all the stuff running at idle and still managed to put out 10 amps current on top of this. I'm really at a loss. I have traced all the wiring and looked for corroded / loose connections and have done a voltage drop test both on the Positive / Negative sides of the charging circuit and it checks out fine. I even had the alternator off and taken it in to be tested and it tests properly. The only thing I can think it might be is the Thermistor (Temperature Sensor) on the battery possibly being bad and maybe affecting the amount of current that is allowed to be pushed into the battery or the ECU is some how signaling to the alternator to keep the voltage high but the current low??? Any help would be great and I thank you in advance. Steve Quote Link to comment Share on other sites More sharing options...
2late4u Posted November 4, 2017 Report Share Posted November 4, 2017 as always how many miles on the vehicle? Quote Link to comment Share on other sites More sharing options...
StevieC Posted November 4, 2017 Author Report Share Posted November 4, 2017 Oh sorry... 80,000km (50,000 miles) Quote Link to comment Share on other sites More sharing options...
StevieC Posted November 5, 2017 Author Report Share Posted November 5, 2017 14.5 = Charging voltage with the engine running 31.2 = AC Voltage while running to test AC Ripple to make sure Diodes are OK 13.0 = Voltage immediately after shut-down. 12.2 = Voltage showing voltage falling. Will get down to 11.5-11.7 If I charge the battery manually it will hold a charge over night of 12.8v and also stays there with a stress test so I know it has got to be something in the charging system. Quote Link to comment Share on other sites More sharing options...
StevieC Posted November 5, 2017 Author Report Share Posted November 5, 2017 The 31.2 volts AC is not accurate. Didn't realize you need a true RMS meter to do this AC-Ripple Test. Quote Link to comment Share on other sites More sharing options...
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