Dead Battery

[JOEA2]

In the Fall I found my battery dead after three weeks without the factory charger. I couldn't figure out why. I put the charger on and the next week it was fine. I kept it on all Winter and two weeks ago I took it out for a run with no problem. I reconnected the charger before covering it.
Yesterday the battery was stone dead as was the charger. I hooked up a Tender and went for lunch. When I came back I noticed that the right brake light was on. I tried tapping the brake pedal but it stayed on and the other two did nothing. I pulled the fuse and it went off and stayed off when I replaced the fuse. There was no power so I left it with the Tender on until I go back next week.:confused
Has anyone experienced this or have any idea what is going on????

 

[BlackICE]

I would replace any battery that ever was fully discharged 2 or more times.

 

[fjpikul]

Joe, there's another recent post about this exact same thing.

 

[JOEA2]

What was the Title?

 

[RALPHIE]

What was the Title?

Here's one...

http://www.fordgtforum.com/forums/showthread.php?p=166263&highlight=brake+light#post166263

Post 23:

...it's the ground strap. Kumar and EP are correct. I had the very same issues. I couldn't understand why one brake light would stay lit, but I couldn't turn the engine over.

I disconnected the battery at the battery terminals and re-attached. The car fired up...then wouldn't re-start after turning off. The disconnect/re-connect cycled the system enough to let me start it each time. It just wouldn't draw enough charge until I paid attention to the frame connection.

Remedy:
Sand away the paint underneath the ground strap where it attaches to the frame thus leaving an uninhibited clear channel for the current to flow.

A couple guys at Rally II had the same issues after tracking. Problem cleared right up after fix.

 

[JOEA2]

My question is about the brake light not shutting off.

 

[Kingman]

My question is about the brake light not shutting off.

As Ralphie points out, disconnect the ground strap from the battery where it attaches to the frame. Disconnecting the fuse is not solving your problem because it doesn't address where the problem exists.

Sand away the paint on the frame where the ground strap attaches.

This should fix your problem.

If you are asking why the brake light stays lit (I suspect you are asking if this is an 'intended warning feature') - I have no idea. That question is better left to someone with expertise in automotive electronics.

 

[JOEA2]

I am trying to figure out what the problem is. The ground was cleaned some time ago. Before that, I had erratic instrument readings, etc. As I said the light seemed to reset when I pulled and replaced the fuse but I haven't been able to check it after charging.

 

[anya]

I would replace any battery that ever was fully discharged 2 or more times.

I just got a BatteryMINDer Plus that claims to be able to revive a sulfonated battery (it may take several weeks) if it is not fried. Appears to do as advertised:thumbsup

Jim

 

[SuperB]

I'm on my third battery.

I have an FM ipod thing that I forget and leave plugged into the Cig Lighter. If I don't drive the car for 3 weeks, it drains the battery. I did the same thing with a navigation device.

I finally decided it wasn't worth it and got rid of that things. Regardless, I try to be sure to start the engine once every three weeks, after a month it usually has lost enough charge that it won't start.

So, my advice is don't plug anything into the Cig Lighter and forget it. And either run the battery tender or run your car every 3 weeks.

 

[BlackICE]

I just got a BatteryMINDer Plus that claims to be able to revive a sulfonated battery (it may take several weeks) if it is not fried. Appears to do as advertised:thumbsup

Jim

Depends on the type of battery. I have read that the spiral wrap AGM batteries may do better than the old style lead plates in acid types. With the old style batteries, once heavily discharged, the lead sulfate that fall off the plates from vibration will never return lowering the capacity of the battery forever. This happens whenever you drive (vibrate) a liquid filled lead acid battery in less than a fully charge state. The stock FGT battery is an AGM type, so I don't know if they suffer as much from use when less than a fully charged.

From:

http://en.wikipedia.org/wiki/Lead-acid_battery

Active material (the positive plate lead dioxide and negative plate spongy lead) changes physical form during discharge, resulting in plate growth, distortion of the active material, and shedding of active material. Once the active material has fallen out of the plates, it cannot be restored into position by any chemical treatment. Similarly, internal physical problems such as cracked plates, corroded connectors, or damaged separators cannot be restored chemically

 

[Fast Freddy]

i see that deltran makes a cigarette lighter adapter for their 12 volt battery tender. since the battery tender is 1.25 amp i assume it is okay to use with our GT's???

the charger that came with our GT's is only .5 amp

can anybody verify this for me?

 

[nota4re]

We sell the Battery tenders with the cigarette lighter adapter on the website.

 

[Kayvan]

The Deltran is fine to use as well.

I use the OEM Charger anytime i go 2 weekends with out driving (down from 4-6 weeks when new); I also try to 50 miles a drive minimum.

I have the OEM battery for 3 yrs and am not sure what the life is; I assume after 3yrs it requires more attention, and 5yrs is max-life.

 

[RADGT]

Just had the same thing happen. I bought a variable charger or at least one with several different amp settings that at the same time tells you the charge state of your battery. Unhooked the terminals first so the brake light would go out. Set the charging on 10 amps and gave it quick charge, still took about 90 min. as it approached 100%, I unhooked and switched it back to the battery tender then waited for it to be completely charged. Car fired right up after that.

Stu

 

[JOEA2]

The battery is now charged(12.8 volts) but there is a drain on it. It is losing
.1 volts every ten minutes.:frown

 

[BlackICE]

The battery is now charged(12.8 volts) but there is a drain on it. It is losing
.1 volts every ten minutes.:frown

Charge the battery fully, disconnect it for 24hrs. If it doesn't stay at or about 12.6 or more throw it out and buy another one.