parasitic draw

[71 demon child]

I'm going to try to make this painless as possible as i am posting this q for a friend and i don't have alot of info.He has a 68 dart convert. /6.The battery is going dead about every 6 days or so.HE has hooked his test light in series with the pos. cable to act  as an indicator and then proceede to unhook things.He said he even unhooked the alternator and that didn't do it.He caught me heading out the door for work so i was trying to leave so i didn't have time to write things down.He said something about an ignition resistor being hot when tested.Is this supposed to be a constant hot lead?Can some of you give me some typical problem areas for this type of problem.Sorry i don't have more info.I haven't even got to look at the wiring schematic myself so i don't know off hand what's where.THanks for the replies.

carl

[SRT440DUSTER]

I don't believe its supposed to be a constant but I'm not looking at the schematic either...are their any accessories that are on when the key is on?...check the radio and heater fuses..if they are lit up with the key off I would suspect a faulty ignition switch

[68dodge]

Possible short in one of the wires. Try pulling one fuse at a time and leave that fuse out. It takes time when doing it this way.  You should be able to find which circut is drawing the battery down. This is just a way I have done it. Maybe someone else knows a better way.

[AAOUTLAW]

First off...check parasitic draw with a digital amp meter and not a test light.
My tool of choice is your basic Fluke model 88 ....AND YOU TEST THIS ON THE NEGATIVE SIDE OF THE BATTERY AND NOT THE POSITIVE SIDE.
You need to know the max parasitic draw rating for the battery is, This is simply the reserve capacity divided by four, or amp hour rating divided by 2.4     this should be on the battery label.
When you start using low impedance devices like test lights to look for draws, Kirchov's laws of electricity come into play and you cannot accuratly calculate the current flow to isolate the circuit.
For example:  100mA doesn't sound like much but it will take a 690 CCA battery from 80% state of charge down to 50% in about 8 days.
First you disconnect the neg. battery post and install the meter in series between the battery and the cable..set the meter to read amps first off and see what it reads...if the reading in not above whatever the meter is fused at for it's miliamps input max rating you then switch it over to read miliamps, compare this reading to your earlier calculations. If it's to high you have to pull fuses and disconnect components till you find the offending draw.
Don't open the doors or overload the meter when it's set on miliamps...it's internal fuse will pop...for a Fluke 88 they are about 8 bucks a crack.  Sometimes finding parasitic draws can suck...especially when they are intermitent.  I have NEVER been able to NOT find one so there's no magic involved...just a logical approach and some detective work. I have been told that wearing a Sherlock Holmes hat while doing this can help but have never personally tested that out.
Also on a special note...if the car has an aftermarket radio, amp, or cd changer installed they are what i would check first...a digital radio needs to maintain a small parasitic draw to keep the clock and station presets alive...  this is usually under 2mA  and thats about a frog farts worth of current.
An excessivly dirty battery will self discharge too...if the top is wet with acid, dirt, road salt and other skronge the electron flow between the 2 posts WILL occur and self discharge is GOING to happen.
Class dismissed

[farmington]

I had a battery go down on me (ooh, that sounds bad!) a while ago.  Turned out to be the map light, which I didn't even know I had.  I accidentally turned it on.

[71 demon child]

Thanks guys.I will give my buddy a call.Good info.I don't know if he has acess to a meter...hence the test light.I'll see if he has a frog fart detector  .

carl

[Jim_Lusk]

The ballast resistor should not be hot while the car is off.

[496dart]

i had the same thing on my dakota. Turns out the dome light(switch) was on,  i didnt know this cuz the dome light has never worked in the truck. I found it by using the mentioned "current draw test" with my meter.

[71 demon child]