Ok in my ef2 xr6 i left the interior lights on overnite. Now ive jump started earlyier, ran 4 15min.
This arvo it would not start again 10.4v so i jump started again and went for 30min drive (ac on max so thermos were going). But at battery place they checked it while running it was 12.9v.
So he said it is the alt. Once turned of it was still high 12's. Ive checked the big fuses near batt and under dash. All are good. What do u think it is?

should have around 14v at battery with engine running a good battery will be about 12v without, suggest you try charging it out of car and getting alternator looked as well, its hard for alternator to properly charge battery from beint too flat

yea tahst what i thought it might be i starte dit an hr ago this batt was 12.4V then when it was running went up to 13.4v so it seems to be charging. when i get to work tomorrow will use clamp meter on alt cable. and i will take batt out and charge on works charger