High voltage? System shut down while driving

FordTechOne · Sep 21, 2020

KingKoopa17 said:
So, thought I'd give a little update: before I left work yesterday I grabbed my DMM for gits and shiggles to check the voltage while the engine was off and got 12.39v. Not sure if this qualifies as checking the battery life. Drove it home, kept a keen eye on the volts the entire way back and stayed at a constant 14.5v. Stopped by my dad's place since he has an OBD scanner and wanted to check for any possible faults and found none. Upon leaving the voltage dropped down to 13v while driving. Drove it today and it was reading only 12v, but it did fluctuate from 12.5v to 14.5v. It did still read 12.4v on my DMM while the engine was off, however. Called the dealership and let the tech know my situation, although he didn't seem too concerned about it. Just said to give them a call if I saw it drop below 12v or experience any other issue. If that's ever the case, I'll be sure to give an update.

Battery state of "health" can only be checked with an appropriate tester, which are quite expensive. Your DVOM/DMM will only show static voltage, which will vary greatly based on current battery usage.

The charging system uses a strategy called "Smart Charge", which Ford has employed for 15 or so years. The charging system is controlled by the PCM, which determines charging strategy based off of current load conditions. This means that the battery will charge under low load conditions (deceleration, coasting, etc) and reduce charging load under higher load conditions (acceleration, pulling hills, etc). This maximizes efficiency and minimizes battery fatigue from over charging. The only time you need to be concerned with the charging voltage is if the battery light or a charging system fault message appears; otherwise it's operating as designed.

High voltage? System shut down while driving

FordTechOne

FRF Addict

Similar threads

Members online

Forum statistics

Latest posts