Okay long known issue with the mustangs. Let my car sit a day or two without being started and you find out it won't start. Has anyone determined what the problem is?

 

if the cars 5 yrs old, might just be battery time...our 09 goes dead in 2 weeks- surely sulfated plates from sitting- but the 06/07 can sit for a month with no startup issues. once had to charge the 06 after 3 weeks- why? who knows...suggest turning off the radio though- recall reading in some cars the amp *might* stay on...and my 06 if a cd left in the radio, after work would notice it was on a different track...is it still 'playing' all day? dunno...also heard locking the doors with the electrical button, or fob acivates security...locking by pushing the manual lock dont- if its locked in a garage, might be worth a try...theres a thread in here somewhere that someone did the amp draw tests on all this stuff to see what changed by how it was shutdown...

the 09 has beed 100% dead a couple times, Schauer's new 'ship and shore' chargers default to a desulfating mode if you dont push any buttons- Ive bounced back battteries that were dead for a year to like new with it...might say 'bad bat' after a few hours, just unplug/try again...the one in my mark VII was 'bad' for a week, resetting 3x a day, but it finally the 'bad bat' msg went away and it ever so slowly started to take a charge- and held it fine...guess it pulses higher voltage briefly to knock sulfate coating off the plates- might take a while, but works pretty good.

 

Ditto on turning the stereo off every time before shutting off the car.

I use a deltran battery tender plus on my Roush and my 32 Ford. It's piece of mind for me as my cars sit a long time during the winter months.

Good luck!!

 

I had the larger Battery that came with the 07 gt/cs how ever it was crap for the factory stereo, ex: if I washed the car & listened to the radio while drying it off 15 mins tops it was dead not enough to start it ! why Ford said the car has four amps in it draws a lot they tested battery & said it's good ? (NOT Enough for me) so I went out & bought an Optima red top , I can have car off with stereo on wash it. wax it, buff it and still loads of juice I also had added a 1600 watt amp as well

 

i've had the dead battery issue twice so far. the car would sit for 2 days tops and would not start on the 3rd day. forget about turning the radio off, it's a crap shoot. the first time i had a problem the replaced my shaker 1000 amps and the car was good for three years. got a new battey about three weeks ago and still left the radio off and it was dead again. took out the fuses for the amp and have yet to have a problem. i also lock the door by pushing down the door pin and do not turn on the alarm. i don't even listen to the radio anymore. will see if this helps any.

 

I dont think anyone ever figre it out....Although I still have my original battery, i keep it under a battery tender.

 

my dads 2005, has had this issue twice now. with the original battery and the replacement.

 

This is a very timely topic. I replaced the battery on my 06 GT in early December, after having it give good service since November of 05. I only had one problem with the original battery at about the two year point. Batttery was drained after the car had not been driven for a week or so (before this time, the car would fire right up after weeks in the garage). Jumped it, took it to Ford, they put in on their charger, said it was fine, and I didn't have another problem with it until shortly after Thanksgiving wheh my wife tried to start the car to pull it out of the garage to wash it.

I went with a Ford replacement, and it seemed to work fine--until last Monday. Went to open the door and I knew that the battery was dead. Pulled it out, took it to Ford, where their tests indicated that it was defective, and gave me a new one. I've charged it, and I'll put in back in the car on Tuesday. So my second battery lasted all of two and a half months! By the way, I have the Shaker 500 and active anti-theft, but, as I've said, my original battery seemed to work fine. We'll see with the new one.

 

still have the battery that came with my car altho it has gone dead a few time from listening to the tunes. 3.6 years of use no alarm

 

FYI: If you are storing your Stang or not using it for several few weeks, just unhook the positive terminal on the battery to prevent the drain down. Down side is you will have to reprogram the window controls. But that is pretty much cake to do per the owner's manual. Or just keep it on the battery tender like we do. CalStang

 

Battery tender FTW

 

When I park the car, I turn off the stereo and set the A/C to fan 1, coldest, and off. It seems to be working so far...

 

I just drive my car almost everyday !

 

It appears that Ford batteries are a hit or miss. I have been through 2 batteries on my 04 F150, also my sons 02 Explorer has the original. So, I keep the Mustang on a battery tender, cant go wrong here.

 

My '06 is a daily driver.

While it is locked while at work, other locations, etc. it is in the garage at night and not locked.

Everything is turned off before the key is turned off.

But I am still on battery #3 in 4½ years.