Technical Finding a battery drain-no plumber crack required.

My old boss had an old electrical meter on wheels with several parameters. Being young I used it as he had it set up to find a drain in a circuit. We would take off the negative battery cable, and connect the meter to the negative post and the negative cable, putting the meter in the ground circuit. We would note the reading on the meter and pull fuses one at a time to see which one dropped the needle, locating the general area of the drain.
What I do not know is what meter we used- amp, volt, ohm.... I never paid attention!
Anyone ever used this procedure?
Thank you
Sherri

 

Amps is what you are looking for

 

Most people use a test light between one battery terminal and the cable that went on it.

The light will be on if there is a draw. Then take out fuses or disconnect things that are not fused. This test is better used for old systems, not modern.

on a modern car, there are things that do draw

 

Did it look like this?

 

The old vat-40
Wore out one and bought another

 

I would use the volt meter to test for draw on a system the higher the voltage the higher the draw.

 

I'd think the ammeter would be more accurate and sensitive, especially when used on a lower amp range scale. To some degree, knowing the amp draw might help you to locate the problem circuit.

 

When I used an amp meter I would make a coil of wire with 10 wrap in it and hook the ends of the wires between the battery cable then hook the amp clamp through the loop of wire and divide my reading by 10.
I would do this for small drains. But that would be on a car with lots of electronics not a traditional hot rod that would have far fewer circuits.

 

Here is a thread that is full of info.
http://www.jalopyjournal.com/forum/threads/how-to-use-a-multi-meter-volt-meter.960762/

 

An old timer showed me the method using the test light. Has worked for me several times.

Had a light staying on in the glove box once and another was a short (or something) on a door jamb switch. The brighter the light the higher the draw.

 

I use a digital volt meter as you can see real small voltage pulls ( 1/2 and 1/4 volts) and its the only way to work on new cars . works good on old cars too .

 

Thank you! CaptainTayTay I believe the one we had was older with one big swing. My old boss was quite crafty!
I am sure that is exactly why we used the meter over the test light, to have an idea how much draw each circuit had to eliminate normal drains like hood light, radio, KAM, and such.
I just acquired a really old multi meter with all the attachments at a farm sale, I think it will work nicely, we have several tractors with parasitic drains. I also bought some type of electric gauge with I believe vacuum on it, something about coils. I will have to look into it, it looks like it was really cool in the '40's!
Thank you for the response and link!

 

probably already mentioned. attach voltmeter between ground cable and the neg battery. select Amps on meter. then unhook each consumer one at a time, or each fuse until acceptable mA found.

 

I always put the test light between the positive post and cable.. Don't know if it makes a difference but it always worked for me...

 

Either way should work as the light will tell you if you have a drain with it hooked up either way as he drain completes the circuit.
I've run across several rigs including one we fought for a number of days that have serious battery drains right across the dirt and moisture on top of the battery. If he top of the battery is the least dirty or moist hook the + lead of the volt meter to the + battery post and use the - lead like a probe across the top of the battery to see if you get any voltage draw across the top of the battery. The one we had all the trouble with was a pickup that would have the battery go dead in less than 3 hours due to a 9 volt draw across the top of the battery.

 

Send us some pictures of these items.

 

Use the volt setting. Some test lights will not show small parasitic draws. Make sure you do not have a door, trunk or hood light on while testing.

 

Here they are. The Motorscope has a copyright date of 1930 on the pamphlet! Pretty cool!

 

Sherri, those are a great find, especially the "Motoscope".
I like........ "INFALLIBLE AS A DOCTOR'S STETHOSCOPE"
They look to be in great condition for there age.

 

If you use a multimeter set to the "Amps" range, be aware that the maximum that the meter will handle will probably be no more than 10 amps. And there is usually an internal fuse that will pop if you exceed the current the meter is designed for. (And that will lead you down the wrong path if you are unaware of the open fuse). Also, some multimeters require you to utilize different test lead jacks for the "Amps" range. I guess the bottom line is to familiarize yourself with the multimeter, if that is your instrument of choice.

 

I will read the info that came with the Simpson, it seems like a newer meter.
CaptainTayTay- I found the pamphlet entertaining, too! Like snake oil, I could hear the sales pitch! LOL I believe with new vac hose it will operate! I used to have a Pontiac with vac gauge in the center console- used to tell you alot about the older engines.

 

That Simpson 260 is an excellent choice for your troubleshooting.

 

Ya, I had a 1965 Pontiac Bonneville with the vacuum gauge in front of center console also.
Would like to have that one back.....

 

I don't have very good luck looking for my shorts. I never wear them.