battery drainage again

[912504x4]

I am fighting a pesky battery drainage problem.
Seems like I always have them

I have the battery negative cables both disconnected. I have my digital voltmeter connected between the negative post and the negative cable.
The voltmeter reads 12.54 -12.56 back and forth.
I am going to recheck in a minute but I cant seem to get it to drain at all.

Something is draining me down and I just took the alternator to the local parts house and it is making 14 amps. Is that enough juice for our trucks?

Anyone have another solution for me?

Thanks, Eric

 

[912504x4]

hhhmmm

I ran up town to change the water bill over from the landlord and when I got back the voltmeter is showing 12.42-12.41 so something is running me down super slow.

Am I correct to think that when the voltmeter is flickering between 12.42 and 12.41 that is the clear sign of a draw?

Thanks, Eric

 

[dieselmanic]

you need to measure battery draw in amps instead of volts. that reading that you have indicated that something is on but not how much it's drawing. this could include memory in the radio or some other electronic device. do you have an ampmeter?? connect the ampmeter as you did the voltmeter and measure the amount. up to .035 amps is accept. more then that will cause a flat battery over time. from your description, it sounds like your alternator is failing. take your truck to azone or some such and they will test your system for free

 

[912504x4]

I took my truck to Advanced auto and they checked my truck charging system with a rollout cart.
They told me that the alternator was bad so I pulled it and took it back to Autozone where it still has a warantee remaining. They tested and found it to be good so I took it to a third party and they tested it to be good also.
This was all done yesterday. I guess my alternator must be 2/3 rds good. :Sly

I pulled the anti-lock brake fuse and the voltage jumped from 12.24 to 12.43.

The antilock brake light has been on also. Maybe I can get lucky and the A-B controller is the problem. I havent been able to make them work since I've had the truck so unplugging the whole mess sounds good to me. (no loss)

More fuse pulling to follow, I am sure
I will try to find my alt. meter
Thanks, Eric

 

[Agnem]

As was stated, stop looking at the volts. Set your meter to amps, and check your draw down that way. There are things in the truck that are always on. The radio clock, maybe some other stuff you've added. These all add up to less than an amp usually. When you look at volts, your only going to see the potential difference, and the volt meter will not pass the actual current needed by what is drawing your battery down, so you will never see anything that way.

 

[dieselmanic]

you can make a cool tool by going down to radio shack and purchase a 1 ohm resister (heavy duty), solder on a lead on each end, and hook it between your ground post and ground cable. (make sure other battery is disconnected.) with the load going thru the resister, now your voltmeter will read amperage. (ohm's law) it's a slick way to make a ampmeter . be CAREFUL not to turn something on that has a high draw because that resister will get HOT quick . but this works great to chase down those hard to find problems .

 

[912504x4]

may have found the problem

I cant get my multimeter to cooperate with me so I am doing the test with an old fasioned test light between the negative post and the negative cable.
When the domelight/glovebox light/ac/heat/radio/courtisey light fuse ( slot #18 on my truck) is in the slot the light is bright as can be but if I pull it out then the light gets very weak and is hard to see.
So, I disconnected the dome light and tried the same trick and nothing changed so I moved on to the glove box light and couldnt see my test light due to hood etc so I will have to try again tomorrow with some assistance by my x brother in law.

Any suggestions of how to test the radio and other items?

Thanks, Eric

 

[dieselmanic]

dude ya gotta have some hard facts. that fuse you pulled supplies power to the radio memory. that's why the light is bright and why you can't use the light to diagnose this problem . as stated, you use about 35ma to power the memorys in the vehicle. SOME draw is normal. now you have too much draw and you have to find out what is causing the problem :Sly soo, get some numbers and let us know.

 

[Agnem]

If you don't have an amp meter, go to Radio Shack and get one of these. For $30 it would be a worthwhile investment.

 

[912504x4]

no radio at all

I have the radio pulled totally out of the dash and totally disconnected for the test even before I pulled the fuse. I thought for sure my speaker amp was the culprit so I checked that out first and then removed both from the circuit to continue testing.

I really have a better multimeter than that but am too stupid to figure out how to get it to show amp draw. When I turn it to that function it shows a
.003 no matter what fuses are pulled. My meter has 4 slots for the leads to connect to it so maybe I have it in the wrong one.

Maybe I should just spend the $30 so I can start living again :Sly

Thanks,
Eric

 

[Pipeliner_86]

Eric, if it seems that your truck is not taking a charge while the engine is running, you can eliminate one possibility, clean the heck out of your batter terminals, and the cables. Had this happen to my truck a few weeks ago, my truck had been hard starting lately, one day I drove out to my folks farm, and while I was there I was going to pull the truck in the shop and clean a few connections and some other stuff. Tried to start the old girl and the battery's were dead. So I removed the batt cables, and cleaned the batt posts until shiney. Cleaned the cables until shine, reconnected every thing, charged the battery's a little and the truck fired right up.
The corrosion was getting so bad between the battery's and the cables that it wouldn't charge across the corrosion.
It's been a couple weeks now and the starter spins over now faster than has in a long time, so real clean connections are important for a healthy charging system.

 

[912504x4]

something in the dome light/radio circuit for sure.

I know for a fact it is the radio/domelight/courtousy lamp/glove box light/cargo light circuit.
The dome light is totally removed. The radio is totally removed. The glove box light will shut off when it is closed.

How do I test the rest of the circuit?

Thanks, Eric

 

[Full Monte]

Digital meters will drift a bit. Don't worry about small changes in the readings as you make them. All auto systems draw down batteries when not running. Usually, it's small drainage that gets replaced by charging when the vehicle is run again. Have you checked the condition of your batteries? An old battery will not be able to store much of a charge and these small drainages will keep you from being able to start the truck.