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Dead battery - get into trunk?

ktp1598

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When I stopped at the local dealership before I bought my car, the first two Mustangs they grabbed keys for were both deader than a hammer. The salesman even said, "if these cars sit for a couple of weeks they kill the batteries."
I've heard the same thing. 2 weeks max, then all bets are off. There's alot of electronics in these cars. Don't forget besides the usual radio memory there's a fob receiver that never turns off. Plus the alarm that was mentioned and even the ECU draws some current.
 

Genxer

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I would vote that the alarm is doing this, unless there is a defect somewhere. I don't have one and no issues here. My car has gone a week without me driving it, and starts the same as if it was a day. Lots of cars have the same type of electronic systems, but not all have alarms. Additionally, if you have installed any aftermarket electronic devices, I would look at those things first.
 

JohnD

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There is a lot of parasitic load on the battery on this car. When I put mine away last fall in 3 weeks of sitting it was below 12 volts. That's not good. I charged up the battery fully and disconnected it, it was still at 12.63 volts when I started it up in March.
 

deep south

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I had the same problem with my convertible a few months ago; parked it for almost 3 weeks and the battery was completely dead. But since then I have parked it for 3 weeks with no problems, so I have put it down to a "one off".

The only difference was the temperature; it was around freezing, and a few degrees below overnight, when I had the problem; it has been a bit warmer since then when I have parked it. So maybe it just doesn't like the cold?
 

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Catching up on my required reading and came across this thread. I too have had to deal with a dead battery by sitting too long unloved in my garage.
I did not think about the advanced security mode drawing extra power, good info to look into, don't really see the need when in locked garage.

One thing I didn't see mentioned in this thread, the Ford Pass app. My app will send me a notice when I haven't driven the car in 3-4 weeks that the battery is getting low and it is shutting down some stuff so the remote start is no longer available. That leads me to thinking the communications might be the draw on the battery (or a combination of both).

Anyways, I use this as my cue to drive it to work the next day or at least start it and let it run for 15 minutes or so and haven't had to deal with a dead battery since. Pretty cool today's technology having your car send you a message................
 

KingKona

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I had a totally dead battery this morning after not driving the 2015 GT Convertible for about three weeks. First off, is that normal?
Dunno.....

Have you replaced the battery? If not, you can't expect much from an 8+ year old battery.

Voltage on the gauge when driving after the jump yesterday and today was between 13.5 (idling) to about 14.5 (on the highway), which seems to suggest the alternator is fine, right?
Those numbers are what the alternator is putting into your battery. Idling/highway has nothing to do with those numbers. But yes, it sounds like your nator is natoring just fine.
 
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Thanks - yeah. I ended up replacing the original battery a number of years ago, and then after a trip last summer, came back to a dead battery again (which was now just over three years old at the point, so out of warranty). I'm fairly certain the alternator is fine, battery just doesn't like to sit for 2-3 weeks. I keep a battery tender on it now when I know I won't be driving it for a week or more.
 

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The battery should start the car after sitting for several days and probably several weeks. Mine occasionally sits for a week and it starts right up. You can also install a battery switch in the hot lead of the battery. They're all over eBay and Amazon for cheap. I bought a portable emergency start battery that I hope I'll never have to use.
Too late now but neg is the better option for that.
 

RagmopInKona

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I just had this issue. The battery dead and jumper cables in trunk.
What I think I am going to do, is goto a bike shop after I measure 3 times, and get a brake/shifting cable for a pedal bike. And connect it to the trunk interior, safety latch release vehicles have for those that are kidnapped . And route the cable to right behind the folding rear seat back. So it be drop seat back, pull cable end(may even use a bike brake lever) and pop the trunk. Yes , I guess I could drop both rear seat backs and crawl into the trunk and pull the safety latch but way to old for that crap, and if you have things in the trunk that be no beano. I don't think this will be that hard of a mod. Or I'll mount a canvas bag to the seat back and put the jumper cables in that. instead of with the jack and gear.
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