Dying Battery or Phantom Drain

[Ozzie]

I'm hoping this isn't the case, but I'll make sure.

I have the DMCH Digital Door Lock ECU, if that helps.

The radio in the car has a detachable faceplate, which i had removed -- I don't know if that would still draw power or not.

I don't think the car has fanzilla, but it does have upgraded fan fail modules.

I'm going to go later tonight with a different multimeter to try and get a different reading. Hopefully, this is all user error...

Yeah the radio's head unit will still draw standby current, w/o the face plate.
Hate to ask but: Sure you're reading it right? Maybe it's showing 16mA...with that digital door lock unit, I wouldn't be surprised that is your car's standby current.

[orbitron3000]

Yeah the radio's head unit will still draw standby current, w/o the face plate.
Hate to ask but: Sure you're reading it right? Maybe it's showing 16mA...with that digital door lock unit, I wouldn't be surprised that is your car's standby current.

I'm fairly certain I'm reading the display correctly. With the dial on the mA it read "00.16". I did notice that when it was reading in terms of Amps, it read "0.016", which would make more sense. I could have mistaken the decimal place on the mA setting for something else. I will try to take a picture of the meter so that the mystery can be solved. Either I can't read the multimeter or my car is watching it's electrical intake...(probably the former)

[orbitron3000]

OK so I've managed to capture exactly what the multimeters say. I set these up with two different multimeters.

The setup is this: I've removed the black (negative / ground) cable from the battery's negative terminal. The red cable remains connected to the battery's positive terminal. As shown in all three images, the red multimeter prong is connected to the VmAO port on the multimeter, and the black prong is connected to the COM port on the multimeter.

In so far as bridging the connection, I've connected the red multimeter prong to the black cable from the car, and the black multimeter prong to the battery's negative terminal. These are the results:

Digital Multimeter, on mA setting:
IMG_20120128_002302.jpg

Digital Multimeter, on A setting:
IMG_20120128_002311.jpg

Analog Multimeter, on 250 mA setting:
IMG_20120128_004441.jpg

I'm hoping other people are as confused about these readings as I am. The analog one (which I know has a working fuse because I replaced it shortly before testing with it) has the strangest results.

On a related note, I tested the voltage on the battery again. It read 12.29 V, a drop of 0.01 V from just about 4 or 5 hours ago.

[Bitsyncmaster]

Looks like your DVM meter fuse is blown for reading current. Very common to blow that fuse by accidently touching the probes to voltage when plugged into current jacks.

Your analog meter is reading 52 ma which is higher than I would expect to see in our cars. That current draw would drain a lot of power from the battery in a week or two.

[Elvis]

+1

to be sure try to measure another circuit with the DMM or turn something on that needs
just some few more milliamps and see what difference the display says.

one of the interior lights, glove box, plug in a cell phone or navi charger...

[Ozzie]

Win: Analog meter.
Good way to isolate the issue to the meter.
Once you get the digital one back up, or you could continue with the analog: You are off on your drain hunt.

[Ron]

Looks like your DVM meter fuse is blown for reading current. Very common to blow that fuse by accidently touching the probes to voltage when plugged into current jacks.

Your analog meter is reading 52 ma which is higher than I would expect to see in our cars. That current draw would drain a lot of power from the battery in a week or two.

+1

Double check, but I believe there are only two options for that particular meter- For measuring amperage greater than 0.4 Amps, you use the Left two probe ports ("10A" and "COM"). For ALL other mesurements use the right two....

If you measured voltage... then fliped to "mA" without moving the probe over to "10A" and the door was open - GOT YA!

[orbitron3000]

+1

Double check, but I believe there are only two options for that particular meter- For measuring amperage greater than 0.4 Amps, you use the Left two probe ports ("10A" and "COM"). For ALL other mesurements use the right two....

If you measured voltage... then fliped to "mA" without moving the probe over to "10A" and the door was open - GOT YA!

This makes the most sense -- the DMM does have a 10A port, so I ought to be able to still measure with it in that one...still have to replace the fuse

[DMC5180]

Not to hijack this thread:

Is their a simple way to add a 12V Li standby Clock/Radio memory battery that could last for weeks/months if the main battery is disconnected during extended periods of inactivity?

[Kevin]

Not to hijack this thread:

Is their a simple way to add a 12V Li standby Clock/Radio memory battery that could last for weeks/months if the main battery is disconnected during extended periods of inactivity?

When considerate auto shops have to disconnect a customer's battery, they use a little device that's basically just a 9V battery that you can plug into a cigarette lighter to retain the memory in all the computers. Not sure how long it'd last for long term purposes, but I know they're cheap and easy to use.

EDIT: Here's an example just to illustrate, doesn't have the best reviews though: http://www.amazon.com/12V-Automotive.../dp/B002C0NP5I