Bump

 

Death runner:
I was told to take an ordinarycircuit tester (the kind wiht a light). disconnect your positive terminal from your battery. put one end of the tester on the terminal clamp , and the other on the battery post. if the light turns on, you have a drain on the battery, if not on, it's your battery.
Be sure you check this also by turning the key on and connecting the tester to the battery and cable, the light will turn on.
If there is a drain, start pulling one fuse at a time and see if the light turns off (with the ignition off).
The fuse that makes the tester turn off, is where the drain is.
I would still take take out your battery and take it to a parts store and get it checked out. the draining and charging the battery from fully drained can hurt the battery sometimes.

Good Luck!

 

You mentioned earlier that, after you jumped the car and it started, you read 12 volts at the battery but 14 volts at the alternator on the same cable? If this was on the same cable, then you should check all your battery cables including the starter. Sounds like you may have bad cables compounding things. It doesn't take much corrosion or a loose connection to cause high resistance.

 

Rick - I'll clean off my connections and try your checks.

I don't have a check light as you mention, but should I be checking resistance with the key in the on position?

When I say I was checking farther back on the cable, I should explain. I was putting the test cable on the actual post of the battery (the top) and then moving it an inch away to the point on the terminal where my accesories attach. It is literally an inch away.

Thanks

 

Resistance must always be tested with the power off. I have some tips on using a volt-ohm-amp meter on my web page:

http://www.4crawler.com/4x4/CheapTri...oUseAnOhmMeter

For amps, you'll also likely want the key off since you are trying to find out what is draining current when the key is off.

And if you get a voltage difference between the battery post and the cable clamped to it, that very test result has found a problem. You have a bad connection there, likely corrosion on the battery post or where the battery cable is attached to the clamp. You should see no voltage drop along that cable (sure maybe some in the mV range due to the internal voltage drop at high current).

 

Awesome thanks 4crawler. I'll check into new cable ends or at the very least clean the ones I have better (They look good).

I am still unsure why I didn't get any reading on the DCma setting with the key off. wierd.

 

When I asked you if the dome light came on when you had the meter hooked up in series with the battery, you said:

If you have the meter in series with the battery and the door open, you don't see the light, right? Then what happens if you take the battery cable and touch it to the battery (thus removing the meter from the circuit)? If the light comes on, then the meter isn't passing current, and that leads me to believe that the fuse in the meter is popped. Most meters are fuse protected from current overload, not voltage or resistance.

 

Midiwall- good ideas. Although you could be correct about the fuse (And I will check), what I meant is that my battery when connected straight (No meter) doesn't even have enough juice to turn on the dome light. The door was closed when I used the meter.

I'll give it a couplke more trys tomorrow.

 

Ahh... okay, then I'm dropping into the "you've got a bad cell in the battery" camp with the other guys.


It sounds more like you have a battery that won't hold a charge, versus something in the electrical system that's quickly draining it. It's very possible to measure the voltage on a battery, have it read 12v (or 11), but it won't put any current into a load.

Voltage and current are two difference things, and the ability to deliver one doesn't not imply success on the other. Voltage is the number of electrons on a wire, current is the force at which they're being pushed down the wire. In a car battery, a dead (or bogus) cell can also give the symptoms that you're having.

 

Replace the battery clamp.

 

I'll get new clamps....I'm just confuse why I don't have a DCma rating. I checked the fuse and it looked good, but I swapped it anyway.

 

I guess I have time since no one seems to have an optima red 34Rlocally, and I know once I find one they won't have the damned spacers.....ARGGGGGH

 

just ponied up and bought the red top. It 109.99 at the zone.....yeah that's right, AUTO ZONE! hahaha

anyway It cranked my truck right up, but I am levaing it disconnected until I get a reading.

I tested it with the new battery and nothing. I cleaned the cable really well....nothing. I think I am going to replace my cable ends, but hopefully I can get a damn reading...geez.

 

Okay, hang on.

So... you buy a new battery, drop it in and it starts the truck. check - we know the battery's good.


You pull the RED cable from the battery, then put the RED meter lead on the RED battery terminal, and the BLACK meter lead on the end of the RED cable.

Switch the meter ON and set it to DCma.

Open the door of the truck (thus activating the dome light)

...and you get NO reading on the meter? Not a "O" or "-" or anything?


Have you ever seen the meter show current? Do you have a small battery around, a AA or somesuch? (don't use a 9v!)

Put the RED meter lead on the knob side of the battery and just touch the BLACK meter lead to the flat end. Does the meter show _anything_? Don't leave the leads like this for too long as you're basically shorting out the battery through the meter, but it should show SOMETHING.

And do NOT do this with the Optima!

 

Thanks midiwall!

I'll try that tomorrow. So I am supposed to open the door to check the resistance

I tested it on a battery when I first got it, but I'll try again.

Maybe I've been putting the black end on the positive of the battery.

Oh yeah and the reading on the meter is "0", but I was expecting 50ma or greater.

I do pretty extensive guitar electronic work and I still am not fluent with a multi-meter. Geez. Thanks for teh help. I'll get this yet.

By the way, My optima came with the spacer attached on top of it...rad!!!!

 

Ummm, no... Not resistance, current. If you try measuring the "resistance" of the battery, the meter's not gonna be too happy about it.


Remember, we're talking about DCma, not Ohms (which is probably shown as an "omega" symbol which is like an upsidedown "u").


[quote]Maybe I've been putting the black end on the positive of the battery.[quote]That's okay too, the current would just show up as a negative number.


Oh WAIT... Is it just a single "O" (like a character) or is it "0.00" (numbers)?

If it's a single "O" then that's probably OVERFLOW - the meter is telling you that the current draw is too large to show you. What're the upper specs on the meter for current? I'd suspect maybe 2000ma?? (that's 2 amps) If this is what's happening, then you have a HUGE drain on the battery. You're looking at around 100 times as much current flow as you should have with the door closed and everything "off".


No sweat, learning is fun... though doing it through a forum like this instead of having someone there going "try this" is a bit hard.


right on!

 

Sorry, I meant current. For some reason resistance came to mind. I am using the DCma setting.

The reading I get is 0.00, one time is switched to 0.01 real quick and then back....

My manual says the maximum input limit for DC/AC current measurement is 400ma. Also the manual says to "remove power from the circuit under test". Does connecting in series with everything off achieve this.....or should I take both cables off and test between the two cables? Now that I think about it that is a dumb question, because there would be no current.

The manual also states "Caution: do not apply voltage to the test leads while the selector is set to DCma. The connection must be in series with the circuit." and "Apply power and read the current"

That seems contradictory How would you apply power and not voltage. wierd.

I guess the best way to learn something is to have a super hard time with it at first...I definitely won't forget this stuff. whewww

 

Current is measured in series, you you have the power source (i.e. battery) then the meter, then the load, then a return to ground at the battery. You don't want to hook the current meter in parallel with the voltage source, that is if you hook the meter to + and - on the battery, you get a big current flowing through the meter and it goes "poof".

And it could be that you have 0 current with everything off, but usually things like radio backup memory, the ECU backup memory, clocks, etc. all pull some current even when "off".

 

I have an alarm, radio memoery, ecu (obviously) and that quartz clock,and a CB...so I expect something. It sounds like polarity makes adifference I will make sure of that as well.

I have a larger non autoranging meter....I need to mes with taht monster too.

 

You might also try setting up a practice setup. Get like a 9 volt battery and say a 1000 ohm resistor clipped to one battery terminal. Then hook up the meter to complete the circuit. You would expect to see 9 mA (9volts/1000ohms) so you at least know ahead of time what reading you should be getting.