battery goes dead

[jbzac]

My 1994 ford ranger battery goes dead when the truck is shut off. I put a new battery and alternator in the truck. Has anyone had this problem?
The battery goes dead after two days of sitting, I can see no lights on or any draw on the battery.

 

[fishon91]

check over everything and make find whats using your battery power while truck is off. shouldn't be your alternator, maybe not even the battery.

 

[simpsonsrules69]

You should do a parasitic draw test. That is were you disconnect the
- batt cable and put and meter between the batt - post and the - cable make sure to have the meter set to amps and it should not be over .01 amps but u should check manufacture spec. and if there is a amp draw start by taking out one fuse at a time till the draw goes away then check that circuit

 

[shadetree]

That is a good suggestion if he is familiar with a volt meter. If not, he can substitute the meter with a common test light. Remove the negative battery cable, connect one end of the test light to the cable, and the other end to the negative battery post.

If the battery goes dead in two days time, the drain is fairly heavy, and will light the light.

Make sure all doors are closed, igniton off, lights off including hood light, glove compartment door is shut. If the test light lights, you have a drain on the battery somewhere. Start by disconnecting the large wire to the alternator, if the light goes out, you have found the source of the battery drain. If the light doesn't go out, start pulling fuses watching for the light to go out.shady

 

[Ranger44]

I really don't like test lights at all. Low or High impedance. They can fry a computer.

A digital multi-meter is a much better choice, and is a much more useful tool to always have around, and is worth the time it takes to learn how to use it.

However, I would agree with the previous statements. Sounds like a parasitic draw. A DMM isn't that hard to use for this test. IIRC, it was above 5 miliamps, or .05 amps (most cars today have higher draws because of all the modules, clock, plain and simple: just more electronics). Anyway, if you do have anything above that, pull fuses till it falls bellow. You should be able to track it down from there, or at least narrow it down.

BTW, have you had any amps, or any stereo equipment installed recently?

 

[Bob Ayers]

I really don't like test lights at all. Low or High impedance. They can fry a computer.

A digital multi-meter is a much better choice, and is a much more useful tool to always have around, and is worth the time it takes to learn how to use it.

However, I would agree with the previous statements. Sounds like a parasitic draw. A DMM isn't that hard to use for this test. IIRC, it was above 5 miliamps, or .05 amps (most cars today have higher draws because of all the modules, clock, plain and simple: just more electronics). Anyway, if you do have anything above that, pull fuses till it falls bellow. You should be able to track it down from there, or at least narrow it down.

BTW, have you had any amps, or any stereo equipment installed recently?

The test light doesn't fry the computer, the Di/Dt from disconnecting/connecting the battery into the circuit does.

And, by the way, 5 mA is 0.005 AMPS, NOT 0.05 AMPS!

 

[LEVE]

You really don't need a lot of tools. Try charging the battery and:

• Remove half the fuses and check the next morning
• If the battery is dead you know the problem is in the fused circuits still left intact
• Recharge the battery and
  • Remove half the fuses and check the battery the next morning
  • See a pattern here?
  If the battery is not dead then
• The problem is in the circuits from which you pulled the fuses, so
• Reinstall half the fuses and and wait overnight
• If the battery is dead,
• The problem is in the circuits where you reinstalled the fuses
• If the battery is not dead,
• You get the pattern here?

This is a "binary Search", it takes some time to isolate the problem down to the circuit that's draining the battery, but it works. Once you've isolated the circuit you can then look at the devices attached to the circuit and likely quickly determine which one is the culprit.

 

[Bob Ayers]

You really don't need a lot of tools. Try charging the battery and:

• Remove half the fuses and check the next morning
• If the battery is dead you know the problem is in the fused circuits still left intact
• Recharge the battery and
  • Remove half the fuses and check the battery the next morning
  • See a pattern here?
  If the battery is not dead then
• The problem is in the circuits from which you pulled the fuses, so
• Reinstall half the fuses and and wait overnight
• If the battery is dead,
• The problem is in the circuits where you reinstalled the fuses
• If the battery is not dead,
• You get the pattern here?

This is a "binary Search", it takes some time to isolate the problem down to the circuit that's draining the battery, but it works. Once you've isolated the circuit you can then look at the devices attached to the circuit and likely quickly determine which one is the culprit.

The test light Shady recommended will do the same thing, you just don't have to wait overnight to see if you have found the circuit with the high
current draw.....