Alternator Not Charging 2011+ Here's Why

[makuloco2000]

Just wanted to pass this info along as some may be experiencing perceived weak batteries or just want to do the occasional checkup before a long road trip and bam you find the alternator is not charging, don't worry just yet here is why....

[shorod]

Very interesting! I just changed the battery on my 2011 SHO about a month ago. I'll have to connect my DS708 and see if I can reset the battery age with that. Hopefully, if not, the system will eventually accommodate the new battery.

-Rod

[makuloco2000]

Originally Posted by shorod

Very interesting! I just changed the battery on my 2011 SHO about a month ago. I'll have to connect my DS708 and see if I can reset the battery age with that. Hopefully, if not, the system will eventually accommodate the new battery.

-Rod

I don't know of any scan tools that will clear the age besides the Ford scan tool. It will accommodate it eventually but it is best to reset the age as it is a major factor in the algorithm it uses to charge it at an optimal rate. Just like the pcm has algorithms to compensate for vehicle aging in the powertrain system.

[makuloco2000]

If the vehicle battery is replaced, carry out the Battery Monitoring System Reset using the scan tool. If the Battery Monitoring System Reset is not carried out, measurement data collected for the old battery is not deleted and future state of charge measurements will be inaccurate. For example, if an old battery has a state of charge of 60% and the new battery has a state of charge of 90%, the BCM will recognize battery state of charge being 30% lower than it actually is. With the battery state of charge being perceived lower than it actually is causes shedding of loads earlier than is necessary. This also impacts the smart regenerative charge system by causing the battery to be maintained at a higher state of charge than perceived by the BCM, reducing fuel economy benefits.

[makuloco2000]

Here is the original Alternator Load Testing video that I refer to that is still the most accurate test even on these new charging systems.