Here is the issue: In my 86 EA81 hatch, I have been having a weird electrical problem for some time.

 

The battery either has been having a fast discharge, over two days it is dead, or, not enough voltage is delivered while in operation, i.e. the voltmeter in the car slowly drops down like the alt is not charging at all.

 

Took alt out, took it to advance, they checked, it is good. I went ahead and setup my Delco 105 amp conversion and installed that anyways. I will post pics of that seperately.

 

Some procedures I have done: is my battery charger only supposed to put out 10 volts when tested with my digital voltmeter? The battery puts out 3.4 volts according to the meter.

 

When I hook the battery charger up to the battery (still in car), when I test the posts with the voltmeter, it shows 3.4 volts.

 

Do I have a short somewhere? Is my battery charger bad? how to check for short? Not even enough juice comes in for any dash lights. Where to turn next?

 

Any and all help would be appreciated.

 

Thanks a bunch.

Hi,

It does sound like you have a faulty battery, you need an ammeter to check properly for a drain on the battery, but if you disconnect the earth lead and with everything switched off, if you lightly touch the earth lead back onto the battery post then you may see "sparks" anything more than a very light spark could indicate that you have something draining the battery when you leave it overnight !.

DaveH

The funny thing is, I really have no idea on how to use it to check for drain.

 

Can someone give me the procedure?

 

Thanks,

Hi,

Do you have a thing called a "shunt" with your ammeter ?,

it should be capable of handling lots of Amps in case there is a serious short.

 

Disconnect your negative lead from the battery - connect you "shunt" cable between the battery neg terminal and the neg lead ( so that the shunt is completing the circuit ), then connect your ammeter to the shunt, if there is a drain it will show on your ammeter.

 

DaveH

The ammeter has two probes and three holes. Obviously, the com hole is the black probe(ground). There is a hole for regular testing, I think it says V and ohms and there is another that has a {10 A} above it. Is that the shunt setting?

 

How to use that?

 

Thanks a bunch,

Basically how expensive was your meter ?, you could try connecting your 10amp wire to the battery neg lead and the com wire to the battery neg post - but if there is more than a 10 amp drain then you might blow your meter, or if yur lucky just the fuse !.

If you dont get a reading then open one of the doors to test it, an interior light should give you a reading of approx 3 amps

 

Good luck !

 

DaveH

To use your meter in the 10 amp current check mode you need to move the red probe wire to the hole connector marked for 10 amps and then turn the selector switch to the 10 amp position. When you are ready to test the circuit you must remember that you have to place the probes in series with the circuit you are trying to measure. If you try to measure voltage, across the battery say, you will blow the fuse in the meter.

 

To place the meter in series, remove the negative lead of the battery and place the red probe on it and the black probe on the negative battery post. You will then will be able to see how much current is flowing. Do not let the any of the leads touch ground of the car or anything else. You need to keep the connections isolated while doing this test.

 

I also recommend you clean the battery connections and try checking the voltage again. It sounds like you have a resistance in the connections.