Why does my batery keep draining?

F

Fastcat

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Mar 5, 2002

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St. Louis

Aug 8, 2004

#1

• Aug 8, 2004

• #1

Beides of an alarm whaat can make my battery drain? I dont believe non of the inside lights are on. My car has been doing this every since January after I let it sit of 3 or 4 months. I bought a new battery but If I dont drive the car for 3 or 4 dats the battery will drain.

 

green

New Member

Apr 26, 2003

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Aug 8, 2004

#2

• Aug 8, 2004

• #2

starter maybe

 

J

jeffbigwood27

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Nov 10, 2003

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oklahoma city

Aug 8, 2004

#3

• Aug 8, 2004

• #3

If I remember right you can use a test light to find out what is draining the battery. First you disconnect the positive side on the battery and put one side of the test light on the battery post and the other on the cable and it sould light up if there is anything draining your battery. Then you can go and start pulling fuses until the light goes off to figure out where it is draing from. Just make sure you have all the doors closed or the interior lights will try to come on. I think this is how you do it. It has been along time so if I said something wrong I am not a expert.

 

F

Fastcat

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Mar 5, 2002

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St. Louis

Aug 8, 2004

#4

• Aug 8, 2004

• #4

how would the starter drain the battery? The battery is drained befoee I even turn the key (dome lights are dimm).

The test light is a good idea.... im gonna try that.

 

F

Fastcat

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Mar 5, 2002

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St. Louis

Aug 11, 2004

#5

• Aug 11, 2004

• #5

I used the test light method and the light stayed on till I pulled 1 fuse... Problem is NOW, that I misplaced my fuse cover plate and I dont know what that fuse is for. Anyone have a fuse diagram or know what the #8 fuse is for?

 

jrichker

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Aug 11, 2004

#6

• Aug 11, 2004

• #6

Fastcat said:

I used the test light method and the light stayed on till I pulled 1 fuse... Problem is NOW, that I misplaced my fuse cover plate and I dont know what that fuse is for. Anyone have a fuse diagram or know what the #8 fuse is for?

Click to expand...

See http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Aug 12, 2004

#7

• Aug 12, 2004

• #7

how many relays are energized when the alarm is on? more than ~350mA draw is frowned upon by installers. add in a short, and all bets are off. just something to remember.
what fuse was the problem? good luck.

 

TheBocSez

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Feb 3, 2004

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Converse, TX

Aug 12, 2004

#8

• Aug 12, 2004

• #8

Recently had the exact same problem. Turned out to be the alternator. Yeah, I didnt think a bad alt could drain a batt either but it seems that if somthing in the alt is grounding it can. I used a multimeter to test mine. I charged the batt which should read approx 12.6v when the car is off (mine was 11.9). I then started the car and turned on the lights and such. The batt should read in the area of 13.5v or higher with it running (mine was 11.6 and steadliy dropping). I replaced the alt and no more problems. Its worth a check. If you dont have a multimeter, its easy to remove and most parts stores will test it for free. Hope it helps.

 

SilikonBlu

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Apr 20, 2004

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Aug 12, 2004

#9

• Aug 12, 2004

• #9

TheBocSez said:

Recently had the exact same problem. Turned out to be the alternator. Yeah, I didnt think a bad alt could drain a batt either but it seems that if somthing in the alt is grounding it can. I used a multimeter to test mine. I charged the batt which should read approx 12.6v when the car is off (mine was 11.9). I then started the car and turned on the lights and such. The batt should read in the area of 13.5v or higher with it running (mine was 11.6 and steadliy dropping). I replaced the alt and no more problems. Its worth a check. If you dont have a multimeter, its easy to remove and most parts stores will test it for free. Hope it helps.

Click to expand...

I had the same problem - battery would die if you didn't drive the car in about a 24hr period. One of the symptoms I noticed was the ammeter gauge (ALT) was running way higher than it normally did. Replaced the alternator and the problem was solved - apparently it had a short in it and was draining the battery when the car was off...

 

stang976

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Apr 13, 2004

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Westchester, NY

Aug 12, 2004

#10

• Aug 12, 2004

• #10

definatley the alternator

 

extozy

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Sep 7, 2003

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Longview, TX

Aug 12, 2004

#11

• Aug 12, 2004

• #11

well my problem is when you drive the car, the battery gauge thing is in the middle, like i suppose it should be, but once you drive the car and use the AC or Light or something, it won't turn on after that... i can't figure mine out, the alternator i guess? but the gauge says its charging.

i also have an electric fan, and i suppose a stock alternator.

 

HISSIN50

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Aug 12, 2004

#12

• Aug 12, 2004

• #12

i would take it to a parts store for free testing of the charging system. with the added info, you could have a bad battery connection or a bad cell in the battery. those will impede even a hypothetical 10G alternator from getting juice into the battery.

the fact that you get by while driving, but then have no start issues (i assume you mean nothing at all happens or clicking happens, while cranking).

a few tests and checks (free) could save you some money. good luck.

 

D

Daggar

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Jul 19, 2004

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Aug 12, 2004

#13

• Aug 12, 2004

• #13

Sounds like another bad alternator diode question. This is allot more common than I'd have guessed. What everyone is saying is correct. Your charging system can "appear" to be operating correctly even when the diode in your alternator is bad. When that component fails, your alternator will work as advertized when the motor is running (alt volts overcoming batt volts) but when the car is off and the alternator is not being powered, the absence of that diode turns your alternator into a really ineffecient motor (being powered by the battery). What's worse is that your serpantine belt won't allow your alternator to be motored. That makes a condition that is about as close to a direct short as you can get without all the fireworks.

 

8

89 droptop

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Mar 7, 2004

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Centrial California

Aug 12, 2004

#14

• Aug 12, 2004

• #14

Do you have underdrive pullies? They don't allow the alternater to charge the battery like it should, The use to happen to me all the time, paired with a faulty alternater this may be the problem. In this case the alternator does not drain the battery, it just does not re-charge it like it should. Thats why you may see your voltage drop when ideling

 

cdog301

Founding Member

Aug 30, 2000

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richmond ,ca

Aug 12, 2004

#15

• Aug 12, 2004

• #15

battery

A quick test to see if your batt is being charged fully is place a DC volt meter on the positive and neg (red and Black) posts of the batt start the car and you should read about 13.5 VDC for a fully charged batt if lower probably the Alt!

 

F

Fastcat

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St. Louis

Aug 21, 2004

#16

• Aug 21, 2004

• #16

The #8 fuse was the problem. I checked to see if any lights are on in the car w/ doors closed, etc. but nothing is on, but when I pull the #8 fuse the test light will go off.

 

jrichker

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Aug 21, 2004

#17

• Aug 21, 2004

• #17

Fastcat said:

The #8 fuse was the problem. I checked to see if any lights are on in the car w/ doors closed, etc. but nothing is on, but when I pull the #8 fuse the test light will go off.

Click to expand...

Do you have any aftermarket items like an alarm system, stereo, instruments, radio, radar detector, etc.? If so one of them may be the culprit. Don't overlook the glove compartment light, it is hard to check with the door closed.