I have a 2007 F350 and recently my battery light has been coming on a few minutes after starting and stays on for several minutes and goes out.This only seems to happen with first run/start of the day and then no issues. TodayI checked both batteries before starting and the voltage was at 12.6, after starting the voltage on both went to 13.9. After about 2 minutes or so the battery light came on (voltage on both batteries remained at 13.9). The battery light remained on for about another 7 or 8 minutes and went out (voltage still 13.9).Shut it down and voltage on both batteries was 13. Do these numbers seem okay? Anyone experience something like this?

 

You need to have the batterys and alternator tested. Replace the battery in pairs if possible. And get the highest amp output alt.you can find or wallet will allow. Charging issues are bad for the FICM and injectors. Ask me how I know?

 

Usually, it's the voltage regulator in the alternator. Like mentioned, have the batteries and alternator tested.

In the single generator system, with the key in the ON position, voltage is supplied through the instrument cluster warning indicator I circuit to the
voltage regulator. The regulator grounds this circuit and the charging system warning indicator is illuminated. When the engine is started, the
regulator removes the ground on this circuit and the warning indicator turns off.

 

You also need to check all of your grounds for good connections. Make sure the batteries are tested indipendant and isolated from each other. If one is flakey replace both.