How is it possible to try and determine what is draining my battery. I have no aftermarket accessories or anything plugged into my 12v outlets to drain the battery. The truck was dead and had to be jumped when I went to start it the other day to pick the little guy up from daycare. I
charged the battery the other day and left the cables disconnected for the night and it fired right off like it was a brand new battery (which it is) the next day. I then decided to leave the cables connected for the next night and when I went to start it the next day something had drained the battery. Only been sitting for about 16 hours.


If I drive it for an extended period of time and head into town it fires up just fine throughout the day. But when I get home and let it sit for a few days it appears as if something is draining the battery and is either completely dead or barely cranks over and then starts. I don't drive it much as I have a work car I bring home. I never had any of these problems until the new battery was installed. It is a 5.4 06 FX4 screw. I am frustrated and getting tired of having to jump it when I have to go somewhere.

 

What year is your truck? Have you done any modifications lately? How old is your battery? Is it starting to get cold where you live? Try this... Unhook your battery... Charge it up overnight. Take a volt meter and first thing and check the voltage of your battery. If it reads 12.0 or less then you have a bad cell in your battery.

 

i had a similar problem with my truck, i bought the truck brand new in 08. within 1 month the battery crapped out, and had to jump it to turn it on, took it to ford and they replaced the battery and havent had a problem since then even with all the audio upgrades i've made.

 

check all your cables for corrosion and good connections...don't forget your starter connection...

 

I had a similar problem and it took me forever to figure it out. One by one I checked the load on the battery removing one fuse at a time to try to narrow it down, and nothing changed. It ended up being a bad diode in the alternator that when sitting would allow the current to flow out of the battery. Leave everything plugged in at the battery, unbolt the cable at the alternator and leave it sit overnight. If the battery is still charged the next day replace your alternator.

 

Some recent info in "need new alternator" on checking for leakage?

https://www.f150forum.com/f4/need-ne...rnator-172831/

 

Here is the deal. Ive had the battery tested, alternator tested and I have checked it for parasitic drain with no results. Relay one clicks in sync with the interior lights on and off. Charged the battery back up Ive taken the fuses out, radio out and still nothing. No light are being left on. That ground on the pass side kick panel is clean and not rusted. The truck wouldnt start when we had a cold snap and then today when it rained 60 degrees out. It sat for 24hrs both times PLEASE HELP ME !

 

How were you checking for the draw? I've seen a lot of radios cause this draw

 

Finally got my drain fixed on my 2004 F150 STX and it turned out to be the factory CD changer. I was so frustrated I took it to the dealer to find the drain. I also seen others mention it in these forums. Even though the radio was turned off the CD changer was running some continuous scan. The dealer pulled fuse #31 and sure enough the drain was gone. I bought a aftermarket radio and now all is fixed. Whew....that was a pain the the azz!

 

^ Bet you're glad that's over with.