The Stovebolt Site Forums The Shop Area The Electrical Bay Battery drain

I have a slow (parasitic?) drain on my battery, it will kill it in about 3-4 days if I don't disconnect it when I park. Is there a way to go to a wire and test it with a meter to see if it is drawing voltage? The only other way I can see chasing it down is to one at a time disconnect each electical item and see if the battery drains then.
My meter is kind of basic (just like my electrical expertise), but if it can be found with the meter I sure would like to know how! Thanks in advance. Ed

a lot of stuff on this subject...do a search...
I gave up on finding mine and installed a battery cut off switch

Thanks, Joker. I was afraid of that. I have a battery cutoff switch installed, but wanted to install a radio and it needs constant power to run the clock and memory. Disconnnect the battery, no clock, no memory. Grrr.

You've got it basically right about disconnecting one circuit at a time but you don't need to wait for the battery to run down. A simple multi-meter will tell you instantly if there's a current draw. If you have current flowing on a circuit with everything off then check the individual components on that circuit the same way.

A drain that will run the battery down in a few days is big enough to power a 12 volt test light. Disconnect the ground cable and connect a test light between the cable and the battery post. If there's a drain, the light will burn. Start disconnecting fuses and/or circuits one at a time until the light goes out, then trace that circuit to see what's causing the drain. Leaky diodes in an alternator can cause this type of drain, and the alternator will still do a pretty good job of keeping the battery charged up.
Jerry

Here's an old trick from a long forgotten source...

1. Remove Ground side battery cable
2. Connect test light between GRD. cable end and battery terminal.
3. If it lights...you have short somewhere!
4. Then, pull fuses one at a time (or disconnect accessory wires one at a time)
until the light goes out........

You could use a meter instead of the light I guess, but a light seems easier in trying to isolate the offending circuit.
mike

Door bell or buzzer is even better you dont have to chase back and forth to check the lite.

Works great in buildings should be fantastic in vehicles.

Dan Bentler

Back when I could still hear it, I used a continuity tester with a buzzer incorporated into the unit. Now I'd need a siren! I've been around too many race cars, jet engines, and high-powered rifles over the past 50 years!
Jerry

Jerry

Aw jeez here I go again cook up a simple solution and find out it is NOT so simple.

I guess in your case long leads to keep light next to you.

Give me a week and I will have solution for when you roll over lite bulb and burn yourself.

Difficult is immediate
Impossible takes a little longer.
Dan

There's several ways to skin that cat. Start with whats powered prior to ignition switch. Test light, power probe, DVM all could be used to find the culprit. I agree with Jerry I too have seen bad diodes in alternators create havoc. Six or twelve volts?

It's a 12 volt '56 1/2 ton, with an alternator. The drain was happening before the alternator installation! I really appreciate all of these tips, I will spend some time with the truck in the next few days and chase this down.
I knew there had to be a way to do this, going to the best site for ol' trucks on the internet and asking a combined 10,000 years of experience was the way to go. Thanks again.
Joker, how was the clock problem solved? Ed

Look on the sun visor bracket in his pic.

lol,
I have another high tech clock in my hot rod
can you find it

The sun dial in the middle of the hood???

lol..for sure a lot of sun in the pix..
the watch is on the floor just in front of the gear shift..
looks much classier in real time...lol

Ed does your truck have a glove box light?If so take the bulb out.Then check,maybe the light is on when the door is closed.My Father-in-law bought a used car that always drained the battery.
as I disconnected the ground to start testing he heard a click.Trying to follow the sound we found a relay,traced the wires.It was connected to a hidden toggle under the dash,which was turned on.Disconnected the curcuit to the switch:Trouble was gone.We never did know what the relay was for.[not a factory install]

No glove box light yet, checked the wire for it but it's well insulated and secure. Hope finding my problem is as easy as that, I'll be looking tomorrow, that's when I plan to take the truck out of commision for a few days to put a firewall mounted power brake setup on it. Thanks again for all the help.