Battery Drain..

[Guest]

OK, long one..
I've recently purchased a Century Overlander 4x4 battery as my other one was going flat overnight. I assumed the old battery was knackered due to the fact the alternator test via the Multimeter read fine. However, I've had my new battery for five days and what d'ya know..get up to go to work and she's dead. No lights, not even a flicker.. Completely dead.
So, next test was a parasitic draw test. Negative terminal off, positive lead on the negative of the battery and the negative to the removed negative cable. ZERO amps drawing which is odd because it should draw at least 20 to 50 milliamps for a normal system.
Anyway, no matter what I do, I can't trace drawn amps and the alternator comes up as fine..
Any other suggestions because I'm about to set fire to the effing thing..

[Lance]

Alternator belt ?

[Dicko1]

Buy a multimeter and make sure the alternator is charging. Hope your new battery isnt stuffed as well. Going below 10.5 volts can kill a battery.

[binda]

In my experience its always been the alternator or a dead cell in the battery.
What does your alternator read when the car is running? No doubt you have charged your battery enough to start by now. I hope anyway.

I've never tested a parasitic draw using your method. How does that work?
I normally just put the multimetre in series with the negative lead, or positive. Which ever is more convenient. And I presume you have only 1 battery mounted?

[mrbitchi]

Do you have an Ultra-Gauge or Scangauge fitted?

Edit:- Just saw your year model so probably not..

[disco stu]

Can you confirm your parasitic drain test is as you described in original post? It sounds a bit convoluted and could be why you're getting zero. As Binda said-normallly just undo one of the terminals and put the ammeter in series in the middle there

[Allan2]

Can you confirm your parasitic drain test is as you described in original post? It sounds a bit convoluted and could be why you're getting zero. As Binda said-normallly just undo one of the terminals and put the ammeter in series in the middle there.

I second that, what you said this is all I have done to establish battery drain.
Allan

[k100dennis]

Maybe diodes in the IC regulator on the alternator. How long between fully charged battery (12.9 - 13.1 volts) and low voltage ? Keep in mind the battery is "flat" at around 11.8 volts.

[Guest]

Hi all,

Sorry about the delay in replying.
Okay so the parasitic draw test first. With the Multimeter, removed the negative clamp from the negative terminal, placed one lead (red) on the clamp and the other on the negative terminal..
I've still not found the source. At the moment, when I get to work or park the car overnight I'm just removing the positive clamp from the battery so it won't drain. I drove from Geelong to the Murray last week, about 300kms roughly, at night and no dimming of lights at all.. Just flickering dash lights. A new alternator is on its way but I'm a bit dubious as to whether it will solve my problems. Can an alternator still charge AND drain the power when the vehicle is off? Diodes? Regulator?

[erad]

Can an alternator still charge AND drain the power when the vehicle is off? Diodes? Regulator?

Yes - if you have one diode stuffed out of the six, it is possible that the other 5 will still pump out enough voltage (and current) to keep the system charged yet when nothing is happening, the dead diode will drain back to earth. It is difficult to test the diodes whilst in situ, because they are mounted in pairs - Diode A and diode B, time three (3 phase). Even if you find the correct phase, you cannot test the diode because they conduct in one way, and block the other way. SO you may have a dead diode, but unless you disconnect it, when you test, the other diode will conduct as normally, so you cannot tell if the 'dead' diode is conducting backwards or not, unless you disconnect them. Depending on the age of the diodes, it may be better to get a new set (of 6) or get a reconditioned alternator.

[Guest]

Ahhh! Well that explains a lot! Well I have a brand new alternator on the way so we'll see how it goes from there. If the problem still persists I might just fix it with some explosives.. 😊

[sharkcaver]

If it was feedback through a diode, you would measure the current flow.

The fact he measures zero parasitic draw, says there is something wrong with either his method or his meter.

if you read what he wrote, he has connected the meter properly, in series with the negative lead.

Q1 - did you set your meter to amperage??

Q2 - Does your meter measure accurate amperage against a known current draw?? I've had meters that give dodgy readings before.


The fact he is drawing down a new battery overnight which shows an N70ZZ being 85Ah of capacity, should mean a reasonable current draw should be measurable. For example, to discharge to 20% over 12 hours, you should see 5Amps or more being discharged.

There has been no comment whatsoever on voltage measurement when the engine is running, voltage when standing nor voltage when the car wont start.

Power = voltage x amperage. So anyone of those two variables could affect the starting capability of the vehicle.

We have no idea on the SOC of the battery, how the battery is performing under load and what voltages are being produced.

The problem with low voltage, such as 12V, is that it doesn't take much to make a huge impact on charge uptake/power delivery. A shitty clamp, earth point or battery cable issue could make a new battery look like its failed.

Me thinks more info is required here to make an accurate diagnosis.

I think there is a big clue in the fact his dash lights flicker. Dash lights are low draw and shouldn't flicker.

[old Jack]

Great post and diagnostic methodology Sharkcaver.

OJ.

[Dicko1]

I,ve also wasted a lot of time chasing leakage that I couldn,t find. Every time I used the meter on particular faults it showed no amperage leak. Frustrating to say the least...CULPRIT....Blown fuse in multi-meter. Often there are 2 fuses in the meter...may be worth checking that they are not blown. I now have 3 multi-meters of varying quality, but in actual fact even the cheapest will give volts and show amps. If its not a blown fuse then as Sharkcaver suggests...his method or the meter. Has the battery earth to body been checked?

[Keithyv]

Most multimeters need you to remove the +ve lead out of its normal spot and put it in a special amperage measuring spot too.