Hi. I'm new to the site. I have a problem with my 1998 f150 (144,000) miles. Yesterday it left me on the side of the road. I was driving along and all my instrument panel went dead, about 5 miles up the road the truck died. The battery was dead. It jump started and I made it home. I changed the alternator ($150.00 bucks) but today it is still draining the battery after driving for about 20 minutes. I had the battery tested under load and it tested O.K. (battery is about 6 months old). I am baffled any help on where esls to look is appreciated.

 

i had a car with a battery that would show 12.4 volts all day long but wouldnt start the car. with the load of all the accessories it would die from time to time at idle. would run for ever once jumped as long as the battery was disconnected. then i found it was low on water and you could see all kinds of sulfate build up next to positive terminal. the battery had a dead and shorted cell and would drain too much from the alternator and the terminals wear corroded. replaced battery and cleaned terminals and all has been good since.

 

It could be a bad alternator you swapped in, but typically when I replace an alternator, I replace the battery too, even if it isn't showing bad yet, because often a bad alternator will wear down a battery too much.