Dying Battery or Phantom Drain

[orbitron3000]

If a diode in the bridge is shorted it will drain the battery and if the regulator is bad it can drain the battery. The only way to know using a bulb in series with the battery is to disconnect the alternator since it is not fused. As bitsyncmaster points out not every load in the car is fused. That is correct but most of the time a drain is going to be on a fused load. We all know the door lock module has a significant standby drain. What I presume the original poster is looking for is something much larger and out-of-the-ordinary. Like a short in the cigarette lighter, door courtesy lights that don't go off, a burglar alarm, etc. My tip is a short-cut to find any large drain quickly with a minimum of test equipment.
David Teitelbaum

Yes, I'm looking for something that would cause the battery to drain in about a week's time if the car is just sitting.

I did replace the cigarette lighter with a similar model that I found on another thread here. I wonder if that could be the problem.

Although colors don't really matter, the Black one always goes in the COM ("common") port. The Red one goes in the Right port unless you want to read amperage between 400Ma = .4 Amps and 10Amps (anything higher can toast the meter).
Sounds like you may have used the two outside ports (a No-No)...recheck your fuses (ALWAYS replace with 'fast blow' fuses).

Yes, one part of the meter can read correctly while others don't.
Did you try what Elvis suggested to test it?

Well that'll probably be a problem -- I had the red in the right most and the black in the left most. That'll teach me to skim the directions...

[orbitron3000]

I have found my leak! It was, in fact, the remote functionality system from DMCNW that I installed. Putting the black prong in the 10A and red in the COM port on the DMM, I was able to replicate the readings I saw on my trusty ol' analog meter. After disconnecting the remote system, I saw a familiar reading of 0.011 A (11 mA). Yay! Clearly, I've mis-installed the remote system, so I'll be spending a weekend or two reinstalling and organizing the rat's nest of wires that currently resides there.

Thanks to everyone for their advice, patience, and support in helping me figure out why my battery was draining so quickly.

[Ron]

If a diode in the bridge is shorted it will drain the battery and if the regulator is bad it can drain the battery.

One shorted diode in the bridge rectifier will not drain the battery.

The only way to know using a bulb in series with the battery is to disconnect the alternator since it is not fused...

The battery don't know/care if a load is fused or not.

=======

Success

Putting the black prong in the 10A and red in the COM port on the DMM,...

Cool Beans!

I hope that's a typo...Black in Black hole, Red in Red hole(s)

[David T]

A shorted diode (or a leaky one) in the diode bridge can certainly drain a battery. I understand the battery can't care about fused and unfused. The point there is even if you pull every fuse and circuit breaker there is no way to disconnect the alternator from the electrical system unless actually remove the wires to it. A moot point now since the problem was not the alternator (in this instance anyway). Diodes are typically blown by jumping the battery but accidentally reversing polarity. Even for a second, once you see the spark, you could have fried one or more diodes.
David Teitelbaum

[DMC5180]

David,

You mentioned Cigarette lighter earlier (I assume you meant the Socket) I would not see that as a source for a drain in and of itself. (empty) It can be a source for a dead short and blown fuse under the right circumstances though.

Example: Many years ago I was asked to look a car that kept blowing a fuse, a mid 80's Cadillac Seville. The fused circuit was the radio/Cigar lighter. Took me about a minute to find the problem. This was a NON-Smoker vehicle, so the lighter was never used and had been removed. It was one of those Lighter / Ashtray combo units. Upon close inspection I found the source of the dead short. Since they did not smoke they used the ashtray for other things as in Loose Change. Somehow a DIME had found its way to the bottom of the 12V socket (dead short). Being that a 12V power socket like that is a simple POS/NEG contact point I don't it as being a source of a slow drain. Of coarse an accessory plugged into it could be.

[Ron]

If a diode in the bridge is shorted it will drain the battery and if the regulator is bad it can drain the battery. The only way to know using a bulb in series with the battery is to disconnect the alternator since it is not fused. As bitsyncmaster points out not every load in the car is fused. That is correct but most of the time a drain is going to be on a fused load. We all know the door lock module has a significant standby drain. What I presume the original poster is looking for is something much larger and out-of-the-ordinary. Like a short in the cigarette lighter, door courtesy lights that don't go off, a burglar alarm, etc. My tip is a short-cut to find any large drain quickly with a minimum of test equipment.
David Teitelbaum

David,
You are one of the hardest people for me to follow on this forum. In all seriousness, please tell me:

As I assume you knew to begin with, not every thing in the car is fused. I happen to have a list saved off of the ones that are hot at all times:
*dip beam relay
*luggage compartment lamp
*glove compartment lamp
*main lighting switch
*fan speed thermal trip
*door lock thermal trip
*cooling fan relay
(and devices behind some of these)

You must know he is not as familiar with this as a lot of us are, so why would you single out the the alternator, especially when he didn't report a charging problem? And why while mentioning it v/s pulling fuses, which is really no different than 'disconnecting' something down the line?
FWIW, I'm sorry if that was your point, but it seems like an odd way to get what he need(ed) to me anyway.

And on the other hand-
You call a point moot, then immediately elaborate on it giving examples and causes???

Me=>

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RE: One diode in rectifier able to draining the battery.
If so equipped, one diode in the diode-trio (not part of the rectifier) can short out and the light can glow and the battery will be drained. I do not see how this can be so with the bridge rectifier.
The alternator will not put out correctly, of coarse, but I believe it take at least two diodes to drain the battery and you need one each, negative and positive, at that.
Please show me how that is not the case:
Below is a schematic of an 3 phase alternator, a stock D Motorola. Assuming the Green Diode is shorted, show me the path (using "conventional flow", IE Positive to Negative) the short takes.

D_Motorolla.jpg

[kings1527]

I have found my leak! It was, in fact, the remote functionality system from DMCNW that I installed. Putting the black prong in the 10A and red in the COM port on the DMM, I was able to replicate the readings I saw on my trusty ol' analog meter. After disconnecting the remote system, I saw a familiar reading of 0.011 A (11 mA). Yay! Clearly, I've mis-installed the remote system, so I'll be spending a weekend or two reinstalling and organizing the rat's nest of wires that currently resides there.

Thanks to everyone for their advice, patience, and support in helping me figure out why my battery was draining so quickly.

Did you ever find out what exactly went wrong with your DMCNW remote system? I think I have the same type of drain happening with mine and I've gone over the install way too many times and found nothing that I've done wrong with the install.