Charging and then discharging going down the road

OK what are you calling discharging in light of rgatihnet1 post.

If a battery is charging at 13.8 (good) and drops back to 12.6 that would not be discharging in my view. If it goes to 12.4 or less than it would be in my view. My Scan Gauge II will stay on for a few seconds reading the battery voltage with the engine shut off. If it is 12.6+ I know all is well.