Howdy Roger,



HOW LONG does it sit before the battery goes dead?


Like was suggested above, remove the red battery cable and start with the 0-10 Amp range (just in case) then switch your el-cheapo DMM (digital multi-meter) to the 0-500ma scale.

Make sure the key and any other accessories are off.

Clamp the RED probe from the DVM to the positive terminal of the battery and the BLACK probe to the red battery cable. [This isn't very important since the meter will simply read a negative number if you hook it up backwards. If it's a mechanical meter it will "peg" below "zero"]

Note the current reading.


Keep in mind that ANY current flow will eventually "kill" the battery if left long enough. And even a disconnected battery will self discharge sitting on the floor. (doesn't matter if it's on concrete [old wives tale], wood or the kitchen table)

Batteries self discharge for a couple of reasons. they chemically discharge (albeit very slowly)

Another way is the current path from acid on top of the battery.

Electrolyte is discharged via evaporation and collects on top of the battery. you know this because when you put a little baking soda on top of the battery, you get a little bubbly action.

That little bit of electrolyte on top of the battery will allow current to flow between the + and - posts. It will be on the order of a few milli-amps to several, but over months it will completely discharge the battery.

You can prove this by simply using a simple cheap DMM or DVM [digital volt meter] like you'd find at Radio Shack etc, to measure it.

Select DC Volts and touch the plus or minus probe on it's respective battery post and drag the other probe across the top of the plastic enclosure between the + and - posts.

You'll measure voltage directly on the plastic if there's ANY acid on top of the battery. Where there's voltage, there's current. It may be small.....on the order of a few milliamps but it's enough to discharge the battery if left long enough.


You're probably going to find that you have something drawing current. you didn't say how long it has to sit before going dead but if it takes a month or two, it's probably the alarm system. It it's happening quicker it may be a light inside that stays on.

Even a stereo system will kill a battery. I have to disconnect my battery in my boat because the stereo memory backup will completely discharge the battery in about 3 months.


Regards,


Rick

 

I have seen a few cases where Anti-theft devices installed with a redundant power wire (one to the unit and one sensing on the ignition switch; or, redundant ground (to keep and sound the unit when it senses the first set being disconnected) will draw on a battery. Over time this eats up batteries at a much faster rate than normal because of the low charge level when starting and the hot charge after start. It tends to eat the #1 cell and eventually will short it.

If everything was working ok up until now, I might see if I couldn't borrow a different 12 volt battery and install it for a few days to see if it does the same thing. If it does, you have a "bleeder" short. If it's ok, time for a new battery.

 

I've had two instances of big parasitic draws. After many many hours of searching, both turned out to be faulty alternators. If a diode dies it will pass current both ways. A bad battery and bad alternator seem to be "chicken and egg" type of thing.

If you've tried everything else, with the battery charged, disconnect the charge wire from the alternator and the wire clip on the alt. and see if that alleviates your parasitic draw by either testing your draw or leave it for a few days and retest battery.

 

heres an update!! Thanks for all he replies!!!!

He took the truck down to the auto parts store (after i told him to see if they would just change the battery to see if that was the problem) and they checked the truck and battery and said the battery is fine. They would not change it out for another.

He will leave the truck at my house tomorrow so i can start checking it out with the info gathered here. Will be back with an update soon...

 

All you have to do is take a test light connect it between the ########, oh never mind it's a ford forum not a dod#e forum. #######

 

Thanks for the help!!!!!

 

Another update: I have taken the advice from some and removed the the battery cable and connected a test light in series. A strong light was lit. I removed all the fuses and light was off started to reinstall and the light came on. Its a IOD fuse? I looked that up on line and i guess its for ignition off items. I than remember my father inlaw tell me about the drivers door pin was broken? I unplug that and the light went from bright to dim. I than put my amp meter in place and the draw is 0.24 amps. I take it was the problem.

My last question is do you think the .24 amp draw is normal or do i have another problem? For hahas i put the bad door pin back in and the reading went up to 3 amps. That i could see why the battery would go dead in a few days. The funny part was the inside light never came on with the broken door pin in as well.

Thanks again!!

 

The door switch connects to the alarm...

 

Woohooo

Fix the door pin and see what happens. A draw of up to approx 50 milliamps is normal on modern computer controlled vehicles (to keep the memories alive in the computers and radios)

Bobby

 

well its all set on its way tonight home!! There was one small problem that was still killing the battery. I thought that i had the problem when i replaced the broken door switch. Its was a reading of 3 amps after the new switch it was .25 amps. I set the metter up facing the windshield got in the cab and shut the door. reading started at .25 amps. Started to turn on items and saw the reading climb. Ok so far. I open the glove box door and the light is on but the reading never changed! I reach over and push the pin switch in and the reading goes to 0 amps!! I release the pin and it gives a reading of .25 amps!!!!! I close the glove box door and the reading does not change!!! I found it, I found it!!!!!!!!!!!!! it looked like the switch was not hitting the spot it was to. I played with the bracket and it worked!! Things are good in the garage!!!!! Glad i finally got it!

So thanks again to all those that helped me out on this. I never knew how to check it if it was not for all of you! Thanks!!!!!

 

Roger,

It sure feels good when you can absulutely identify the problem doesn't it. Good for you!

On battery draws I always start with the quick and obvious...glove box lights, trunk lights, and underhood lights (that and people accidentaly turning the interior lights on)

Again, conngrats
Bobby

 

i never had enough time to just spend like all day on it, just here and there. Like always in a hurry. What threw me off was when i changed to a different battery it lasted a week, than went dead instead of the 2 days like it was? After i found out wat was wrong it dawned on me why it lasted that week i was in the glove box getting the manual out! After that i went back in to get a paper out and it went dead. Somehow the switch was made before but stopped after i was in last.

It does feel good!!! Now if i can only figure out my other issues on my 55f100!! LOL

 

Having a second look at this post - perhaps I should have said "Do Nothin" It's the In-Laws Truck.

 

Lucky for me i have inlaws instead of outlaws!! They do more for me than my own family! Truth be said.